Do you know how many make up the human backbone

Do you know how many make up the human backbone

ЛЕКЦИЯ № 9. Skeleton

The bones of our body make up a skeleton. The skeleton forms about 18% of the weight of the human body.

The skeleton of the trunk mainly consists of spinal column made of a number of bony segments called vertebrae to which the head, the thoracic cavity and the pelvic bones are connected. The spinal column consists of 26 spinal column bones.

The human vertebrae are divided into differentiated groups. The seven most superior of them are the vertebrae called the cervical vertebrae. The first cervical vertebra is the atlas. The second vertebra is called the axis.

Inferior to the cervical vertebrae are twelve thoracic vertebrae. There is one rib connected to each thoracic vertebrae, making 12 pairs of ribs. Most of the rib pairs come together ventrally and join a flat bone called the sternum.

The first pairs or ribs are short. All seven pairs join the sternum directly and are sometimes called the «true ribs». Pairs 8, 9, 10 are «fal-se ribs». The eleventh and twelfth pairs of ribs are the «floating ribs».

Inferior to the thoracic vertebrae are five lumbar vertebrae. The lumbar vertebrae are the largest and the heaviest of the spinal column. Inferior to the lumbar vertebrae are five sacral vertebrae forming a strong bone in adults. The most inferior group of vertebrae are four small vertebrae forming together the соссух.

The vertebral column is not made up of bone alone. It also has cartilages.

make up – составлять

mainly – главным образом

thoracic cavity – грудная впадина

spinal column – позвоночник

Если после конструкции there is (there are) стоит неисчисляе-мое существительное во множественном числе, вместо опущенного неопределенного артикля часто (не обязательно) употребляется слово «some».

Вставьте артикль, где необходимо.

1. There is… sofa in… corner of… room.

2. There are… cushions on… sofa

3. There are… books on… shelf. Give me… book, please.

4. Look into… refrigerator. What can you see on… shelves?

5. There is… butter in… butter-dish.

6. There is. sausage, but there is no… cheese.

7. There are… eggs,… apples.

8. There is… orange,… lemon, and… some jam in… little vase.

9. There is juice in this… cup. May I drink… juice?

10. There are… girls in… yard, but I can see no… boys. Where are… boys?

11… boys are playing football at… stadium.

12. I have. colour TV-set… TV-set is on… little table in… corner of… room.

13. There is… book,… pen, and… paper on my… writing-desk.

14. My… brother is… teacher. He works at… school.

15. He has… very good books. His… books are in… big bookcase.

16. There is… tea in my… glass. There is no… tea in my… friend’s… glass.

17. His… glass is empty.

19. There is… cup on… coffee-table and… newspa pers.

20. There is. coffee in… cup.

Answer the questions.

1. What do the bones of our body make up?

2. How many per cents does the skeleton form?

3. What does the skeleton of the trunk mainly consist of?

4. How many bones does the spinal column consist of?

5. What groups are the human vertebrae divided into?

6. How many groups are the most superior?

7. How is the first cervical vertebra called?

8. Are the first pairs or ribs short?

9. How is the second vertebra called?

10. What forms the соссух?

Make the sentences of your own using the new words (10 sentences).

Find the definite and indefinite articles in the text.

The Skeleton

The skeleton is the bony framework of the body. It consists of 208 bones of various size and shapes. The skeleton gives support to soft tissues. It protects delicate structures such as the brain, the heart and the lungs. The joints, cartilages and ligaments between the bones determine the degree and the quality of the motion. The bones forming the skeleton are divided into the bones of the head, the bones of the trunk, and the bones of the upper and lower extremities.

26 bones of the head form the skull which protects the brain. The bones of the trunk are the spinal column ( spine ) and the thorax. The thorax includes 12 pairs of ribs and the breastbone. In the spine there are 7 cervical, 12 thoracic, 5 lumber, 5 sacral vertebrae and the coccyx.

The arms join the body at the shoulder. The shoulder is formed of two bones – the collar-bone ( clavicle ) in front and the shoulder-blade ( scapula ) behind. The bones of the upper extremity are humerus, ulna and radius. The bones of the lower extremity are femur, tibia and fibula.

The skeleton gives the upright strength to the body. The bones serve as a storehouse for calcium and phosphorus.

Match the bones of the skeleton and its functions

Fill in the gaps using the text

1. The skeleton is ….

2. The skeleton protects …

3. 26 bones of the head …

4. The bones of the trunk are …

5. The thorax includes …

6. In the spine there are …

7. The shoulder is formed …

8. The bones of the upper extremity are …

9. The bones of the lower extremity are …

Answer the questions

1.What do the joints, cartilages and ligaments determine?

2.What groups of the bones form the human skeleton?

3.What do the bones serve as?

Make up the sentences

Which part of the skeleton is the most important?

Which part of the skeleton is the most important?

-The most important part of the skeleton is the backbone.

What classes do the naturalists divide all the animals into?

-the naturalists divide of the all animal into two classes: vertebrates and invertebrates

What do the bones of the body include?

-The bones which form the body include the bones of the head, the bones of the trunk, the bones of the lower and upper limbs.

Where is the skull? What do the bones of the head include?

-At the upper end of the backbone. Inside the skull there is the brain. The bones of the head include the bones which make up the box-like structure, the skull, and freely movable bone which forms our lower jaw.

What do the bones of the trunk include?

-The bones of the trunk include the spinal column, the ribs and the breastbone.

Which organs do the ribs protect?

-Ribs protect the lungs, heart and organs of the mediastinum

How does the wrist work?

-the wrist does flexion, extension movements

How many bones are there in the framework of the wrist and hand?

-we have twenty-seven bones in the framework of the hand and wrist alone.

II. The Cardiovascular System. Blood.

What is the cardiovascular system? What does it include?

—The cardiovascular system is the system of blood circulation. The cardiovascular system includes the heart, the arteries, the veins and the capillaries of the human body.

2. What is the center of the circulatory system?

-The center of the circulatory system is the heart.

3. How many chambers does the heart have?

— The heart is a hollow muscle which has four chambers: two ventricles and two auricles.

4. What do the left and the right heart do?

-The right heart receives blood from the veins and pumps it into the lungs. From the left heart the well-oxygenated blood moves into the aorta.

5. Name two valves in the heart.

-Tricuspid valve. The mitral valve.

6. Which types of vessels do you know?

— Types of vessels are arteries, veins, capillaries.

7. What is the blood?

— The blood is a red fluid, which clots when escapes from a blood vessel.

8. Which types of blood cells do you know?

-Erythrocytes (or red blood cells) provide oxygen to tissues, lymphocytes form our immune system, and leucocytes (or white blood cells) defend the organism from infection.

III. The Respiratory System. Respiration.

Why is respiration so important?

— It is important, because it sustains life, and interruption of breathing causes death.

What gases are involved in breathing?

— Breathing includes two main gases: oxygen and carbon dioxide.

What parts of the respiratory system does the air pass on its way to the alveoli?

— Air is breathed through the mouth or nose into the oral cavity, or pharynx. It then passes through the voice box, or larynx, into the windpipe, or trachea.

Describe the mechanism of breathing.

— Respiration consists of rhythmically repeated inhalations and exhalations. An inhalation involves a contraction of muscles, an expansion of the lungs.

Inhalation is followed by exhalation. The muscles relax, the lungs become compressed.

— Respiration consists of rhythmically repeated inhalations and exhalations. An inhalation involves a contraction of muscles, an expansion of the lungs. Inhalation is followed by exhalation. The muscles relax, the lungs become compressed.

How many respiratory movements do the people do?

— An adult makes 16-20 respiratory movements per minute, children make more movements.

7. When does increased respiration occur?

— increased breathing is possible with exercise and some diseases.

IV. The Structure and Function of the Digestive System.

Where is the largest cavity of the body situated?

— The abdomen is the largest cavity of the body.

What organs does the abdominal cavity contain?

— The organs of the abdominal cavity are the liver, the gall-bladder, the stomach, the intestines, the pancreas, the spleen, the kidneys and the bladder.

Why is the liver so important?

— The liver is important, because it secretes bile which participates in the digestive process and has a defensive function.

What does the gall-bladder serve for?

— The gall-bladder lies beneath the right lobe of the liver and serves as a bile reservoir.

What is digestion?

— Digestion is the breakdown of food into smaller components that can be absorbed into the bloodstream.

What is the urinary system?

— The urinary system is the system which excretes the largest part of the waste products of the body.

Where is urine formed?

— The urine is formed in the kidneys from.

What does urine consist of?

— The wastes are excreted as urine, which is normally composed of approximately 96 per cent water, plus urea and various salts.

VI. Our University

When was the BSMU founded?

— Bashkir State Medical University was founded in 1932.

Which part of the skeleton is the most important?

-The most important part of the skeleton is the backbone.

Поперечные профили набережных и береговой полосы: На городских территориях берегоукрепление проектируют с учетом технических и экономических требований, но особое значение придают эстетическим.

Механическое удерживание земляных масс: Механическое удерживание земляных масс на склоне обеспечивают контрфорсными сооружениями различных конструкций.

Организация стока поверхностных вод: Наибольшее количество влаги на земном шаре испаряется с поверхности морей и океанов (88‰).

THE SKELETON AND MUSCLES

The human skeleton is made up of more than 200 bones. It gives our muscles a firm place to anchor themselves and also protects our body’s more fragile organs. For example, the brain is protected by the skull and the lungs are protected by the ribs. The bones of our skeleton vary in shape and size to fit their function. The spine has 33 separate bones. It is shaped to protect the spinal cord, which travels through it, while also giving the spinal muscles a place for attachment.

The male skeleton is different to the female skeleton. Foe example, the female pelvis is specially designed to allow a baby’s safe journey down the birth canal.

Bones have an outer layer called the periosteum. This contains nerves and blood vessels. Underneath lies the toughest part – compact bone. This part is hollow and is lined with spongy bone, which makes it strong but not too heavy. Cells in the bone take calcium and phosphorus from the blood to keep the bony substance hard. Bone marrow lies as the centre of bone. The bone marrow at the end of long bones is responsible for making new blood cells.

We have lots of muscles of different shapes and sizes, ranging from the large gluteus maximus on which we sit, to the tiny muscles that control the movements of our eyes. Many of our movements – when riding a bicycle for example – involve a number of muscles that have to work together, and these are controlled by the brain. Every muscle in our body is made up of muscle fibers. Messages from the brain can make muscle fibres contract, making them shorter. As they shorten they become more powerful and are able to pull the bones to which they are attached. This causes movement.

Although we can control many of our muscles, we also have muscles in our body that work automatically. These include the muscles that make our heart beat and the muscles in our intestine that help us to digest food.

II. COMPREHENSION CHECK.

1. Decide which of the following interpretations is most likely to be true:

a) The skeleton is a firm structure to which muscles are attached.

b) The skeleton does not determine the shape and movements of the body.

c) The skeleton protects more delicate organs from injury.

d) 33 separate bones of the spine are shaped to protect the brain.

e) Bones do not have any outer layer.

f) The bone marrow is responsible for making new blood cells.

g) The outer layer of the bones contains nerves and blood vessels.

h) Cardiac muscles, smooth muscles, glands work automatically.

2. Give answers to the questions below:

a) What role does the human skeleton play?

b) What is the structure of the bones?

c) What causes the movement?

d) Which muscles work automatically?

e) How do muscles range in size and shape?

f) Do male and female skeletons differ?

3. Find in each paragraph the sentence which conveys the main idea.

III. LANGUAGE FOCUS.

1. Form the derivatives of the words given in the chart below (Where possible):

2. Find in the text: a) synonyms and b) antonyms to the following words and word combinations:

3. Complete the sentences below choosing appropriate words from the text:

b) …… contains nerves and blood vessels.

c) …. is responsible for making new blood cells.

h) …. to keep the bony substance hard.

4. Translate the sentences into English using the vocabulary of the Unit:

а) Кости составляют скелетную систему, которая обеспечивает структурную поддержку организма, предоставляют места для прикрепления мышц и защиту органов.

б) Плотные кости пронизаны кровяными сосудами и нервами. Их ткани толще и могут выдержать значительный вес и давление.

в) Губчатые кости содержат пространства, заполненные костным мозгом, который вовлечен в создание кровяных клеток.

д) Клетки костей забирают кальций и фосфор с тем, чтобы костное вещество оставалось прочным.

IV. FOLLOW-UP ACTIVITIES.

1. Discuss the following in pairs:

Muscles and bones work together.

2. Write an essay about the skeletal system.

ADDITIONAL TEXT

I. Read the text carefully. Be ready to fulfil the tasks that follow.

BONES AND MUSCLES

Muscles and bones work together. The bones make up the skeletal system, which provides structural support, sites for muscle attachment, and organ protection. Osseous tissue, or bone, as it is more often called, consists of cells and collagen fibers interspersed in a matrix of intercellular material containing calcium phosphate and calcium carbonate, which are responsible for hardness. Together, these substances account for two-thirds of the weight of bones, while the collagen fibers, which reinforce the tissue, account for the other third.

In addition to bone, another important connective tissue in most skeletal systems is cartilage, which unlike bone, is both firm and flexible. Bone is usually considerably harder and more brittle. Most sharks and rays have skeletal systems composed of all cartilage and no bone. Some other “primitive” groups of fish have less bone than cartilage in their skeletal systems. In most other vertebrates, however, cartilage is located only where firmness and flexibility are needed, such as in joints, nose, ears, larynx, and trachea. During the development of the skeletal system of these vertebrates, the embryos begin with cartilaginous skeletons. Gradually most of the cartilage is replaced by true bone.

Depending on the construction of the particular bony tissue, it can range in consistency from being completely spongy to being very compact. The spongy bone contains many spaces filled with marrow which is either composed of fat or involved in the production of blood cells. In the case of relatively lighter animals such as birds, the spaces may be filled with air sacs. Compact bony tissue is thicker and usually involved in support. Such bones can resist considerable weight and stress.

Compact bones are penetrated by blood vessels and nerves through small narrow openings, some of which are known as Haversian canals, whose microscopic structure is identified by the characteristic concentric rings of bony tissue surrounding them. These rings are composed of cells that were involved in producing the bony tissue. Spongy bone doesn’t contain Haversian systems, nor does cartilage. Materials are exchanged through the blood vessels and bone cells that penetrate the Haversian canals. This is the only way for materials to move to and from the cells living throughout bony tissue.

The movement of different parts of the body all depend on muscular contraction, on the location of the origins and insertions, and on the type of joint involved. Muscles usually work antagonistically. That is, when one group of muscles contracts, it will pull part of the body one way. Alternately, when the antagonistic group of muscles contracts, it will pull the same body part in the other direction.

II. POST-READING TASKS.

1. Discuss the following questions:

a) What substances are found in skeletal systems? What are their functions?

b) How do muscles work antagonistically?

2. Write an essay describing the structure of the skeletal system.

UNIT 7

I. PRE-READING AND READING TASKS.

1. Study the vocabulary to avoid difficulties of understanding:

2. Try to guess the meaning of the following words and word combinations:

3. Read the text carefully to fulfil the tasks that follow.

THE BLOOD SYSTEM

Our blood acts as a transport system, carrying substances around the body. It is rather like a road network, with large arteries as main roads and very small vessels as lanes. Blood itself is made up of a liquid called plasma and two main types of cell – red cells and white cells. Red cells contain a chemical called hemoglobin, which is responsible for carrying oxygen to all the body’s cells. White cells to attack invading germs. There are also small particles in blood called platelets, which help the blood to clot when we cut ourselves.

The bleeding stops when enough platelets have stuck to the broken walls and signalled other substances to come. These substances form strands called fibrin, which form a web over the red blood cells to create a clot.

The walls of arteries and veins are made up of three layers. Arteries carry blood away from the heart veins carry blood back to the heart. Small arteries and veins are linked by tiny tubes called capillaries.

The heart is the muscular organ that causes the blood to circulate in the body. The heart of birds and mammals is four-chambered pump composed of left and right atrium and ventricle.

All cells, in order to survive, must obtain the necessary raw materials for metabolism, and have a means for the removal of waste products. In small plants and animals living in an aquatic environment, these needs are provided for by simple diffusion. However, as the size of the organism increases, and diffusion cannot provide sufficient means for transport. Therefore, larger animals have developed a system of internal transport, the circulatory system.

Blood is the vital tissue in the circulatory system, transporting nutrients and oxygen to all the cells and removing carbon dioxide and other wastes from them. It transports hormones, which affect organs sensitive to them. Blood also acts to regulate the acidity and alkalinity of the cells via control of their salt and water content. In addition, the blood acts to regulate the body.

Some components of the blood act as a defense against bacteria, viruses, and other pathogenic organisms.

II. COMPREHENSION CHECK.

1. Provide evidence from the text to support or disprove the following statements:

a) The blood system is like a road network.

b) Hemoglobin is responsible for carrying oxygen to the lungs.

c) The main function of white cells is to destroy germs.

d) Arteries are thinner than veins.

e) The ventricles propel blood to the lungs.

f) Metabolism and the removal of waste products are provided for by simple diffusion in plants and animals.

g) The circulatory system of larger animals is an efficient system for material exchange.

h) Blood regulates the body temperature.

2. Use the information from the text to answer the questions:

a). What is blood made up of?

b). What are platelets and what do they help to do?

c). When does the bleeding stop?

d). How is a clot created?

e). What are capillaries?

f). What does the heart of mammals consist of?

g). What must all cells have in order to survive?

h). What is the circulatory system?

i). What are the main functions of blood?

j). How is blood loss reduced?

3. Restore the logical order of the main subtopics of the text:

a). Material exchange in organisms of different types.

b). Different kinds of blood vessels.

c). The main components of blood and their role.

d). Important functions of blood.

e). A clotting mechanism.

f). The role of the heart in the blood circulation.

III. LANGUAGE FOCUS.

1. In each box below match the words which are: a) similar or b) opposite in meaning:

2. Match the following words with the right definitions:

3. Change the words in capital letters to fit the context of the sentence:

a) These substances form a web over the red cells ……. a clot (CREATION).

b) The heart causes the blood ……… in the body (CIRCULAR).

c) In order to survive all cells must have a means for the ……. of waste products (REMOVE).

d) The cells of small plants and animals are very near the external …. medium (WATER).

e) …… cannot provide sufficient means for transport (DIFFUSE).

f) The ….. to land requires an efficient system for …. exchange in non-aqueous …… (MOVE, MATER, SURROUND).

g) This system consists of an ……. network of …… vessels (EXTEND, VARY).

h) Blood acts to regulate the …… and ….. of the cells (ACID, ALKALINE).

4. Try to say this in English using the vocabulary of the Unit:

а). Кровь состоит из жидкости, называемой плазмой, и двух основных типов клеток: красных и белых кровяных клеток.

б). В крови содержатся небольшие частицы – тромбоциты, которые помогают крови сворачиваться.

в). Эти вещества образуют нити, называемые фибрином.

д). Все клетки должны получать необходимое сырье для метаболизма.

е). Клетки небольших растений и животных расположены близко к внешней водной среде, таким образом питательным веществам и отходам не приходится перемещаться на большое расстояние.

IV. FOLLOW-UP ACTIVITIES.

1. Name: a) the main components of the blood system and describe their functions, b) the most important functions of blood.

2. Talk about: a) the main blood vessels and their role, b) the difference in the raw materials supply and the removal of waste products in small plants and animals and larger animals.

3. Write a paragraph describing the blood system.

ADDITIONAL TEXT

I. Read the text carefully to fulfil the tasks that follow.

BLOOD

Like muscle, bone, cartilage, and nerves, blood is a type of tissue, a collection of similar types of cells and the associated intercellular substances that surround them. Tissues are categorized into four main types: 1) epithelium, 2) muscle, 3) nervous, and 4) connective. Connective tissue includes blood, lymph, bone, and cartilage. In the case of blood and lymph, the base substance, or matrix, is a liquid. What differentiates these two from other tissue types is that they are not stationary. Blood is a fluid flowing through blood vessels throughout the body (lymph runs through the lymph vessels).

Blood accounts for about 8 percent of a human’s total body weight, amounting to an average of four to six liters per adult (over a gallon), depending on individual size. Blood is thicker (more viscous) and slightly heavier than water. And, depending on the organism, blood is usually slightly warmer than the animal’s body temperature. While the core body temperature of most humans is 37 o C (98.6 o F), their blood is about 38 o C (100.4 o F). Blood pH is slightly alkaline, ranging from about 7.35 to 7.45. Its salt (NaCl) concentration normally varies from about 85 to 90 ppt (parts per thousand), or two to three times the concentration of sea water.

II. POST-READING TASKS.

1. Define the following concepts: blood, plasma, serum.

2. Name: a) the main types of tissue, b) the kinds of connective tissue, c) the constituents of plasma, d) types of blood cells.

3. Explain what differentiates: a) blood and lymph from other tissue types, b) blood from lymph, c) blood from water.

4. Write an essay describing the structure of blood.

UNIT 8

I. PRE-READING AND READING TASKS.

1. Study the vocabulary which is intended to aid your comprehension of the text:

2. Make sure you know the meaning of these words and word combinations:

3. Read the text carefully to fulfil the tasks that follow.

What is DNA?

Do you know what makes up the backbone of DNA?

The famous double-helix?

Read on to find out.

What Is DNA?

Deoxyribonucleic acid (DNA) is a chemical found in the nucleus of cells and carries the ‘instructions’ for the development and functioning of living organisms.

It is often compared to a set of blueprints since it contains the instructions needed to build cells.

These instructions are divided into segments along a strand of DNA and are called genes.

Genes are a DNA sequence that code for the production of a protein and control hereditary characteristics such as eye color or personality behaviors.

Proteins determine the type and function of a cell, so a cell knows whether it is a skin cell, a blood cell, a bone cell, etc., and how to perform its appropriate tasks.

Other DNA sequences are responsible for structural purposes or are involved in the regulation and use of genetic information.

Structure of DNA

The structure of DNA can be compared to a ladder.

It has an alternating chemical phosphate and sugar backbone, making the ‘sides’ of the ladder.

(Deoxyribose is the name of the sugar found in the backbone of DNA.)

In between the two sides of this sugar-phosphate backbone are four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G).

(A grouping like this of a phosphate, a sugar, and a base makes up a subunit of DNA called a nucleotide.)

These bases make up the ‘rungs’ of the ladder, and are attached to the backbone where the deoxyribose (sugar) molecules are located.

The chemical bases are connected to each other by hydrogen bonds, but the bases can only connect to a specific base partner – adenine and thymine connect to each other and cytosine and guanine connect to each other.

The arrangement of these bases is very important as this determines what the organism will be – a plant, an animal, or a fungus.

This is called genetic coding. For example, one side of DNA could have the genetic code of AAATTTCCCGGGATC. Its complementary side would then have to be TTTAAAGGGCCCTAG.

Even though the shape of DNA is often described as a ladder, it is not a straight ladder.

It is twisted to the right, making the shape of the DNA molecule a right-handed double helix. This shape allows for a large amount of genetic information to be ‘stuffed’ into a very small space.

In fact, if you lined up each molecule of DNA in one cell end to end, the strand would be six feet in length.

DNA Replicates Itself

Before a cell can divide and make a new cell, it must first duplicate its DNA.

This process is called DNA replication.

When it is time to replicate, the hydrogen bonds holding the base pairs together break, allowing the two DNA strands to unwind and separate.

The specific base pairing provides a way for DNA to make exact copies of itself. Each half of the original DNA still has a base attached to its sugar-phosphate backbone.

A new strand of DNA is made by an enzyme called DNA polymerase. It reads the original strand and matches complementary bases to the original strand.

(The sugar-phosphate backbone comes with the new bases.)

New strands attach to both sides of the original DNA, making two identical DNA double helices composed of one original and one new strand. Please note that the above explanation of DNA replication is highly simplified.

How DNA Is Used

All living things – plants, animals, and humans – pass DNA from parents to offspring in the form of chromosomes.

In humans, 23 chromosomes are passed on from the mother and 23 chromosomes are passed on from the father, giving the child 46 chromosomes.

Chromosomes carry genes from the parents, but not all the genes of a parent are sent along.

For each child, different sets of genes are passed on from the parents, resulting in unique DNA for each child. This means that even though the genetic code for all human beings is 99.9% identical, no one has the exact same DNA code except in the case of true identical twins.

Knowing this, DNA can be used to identify people in a variety of situations. This field is known as forensic science.

DNA is often used to solve crimes by identifying victims and suspects while at the same time ruling out innocent people as possible suspects for a crime.

It is also used to prove or disprove family relationships, identify missing persons, and identify the victims of catastrophes who are no longer physically identifiable.

And since DNA can be found in a variety of human tissues and fluids such as hair, urine, blood, semen, skin cells, bones, teeth, and saliva, it greatly aids in identification when other methods, such as fingerprints and teeth structure, are no longer usable.

The medical field also uses DNA. Now that doctors at least partially understand how DNA works, modern medicine has made advances in identifying diseases and finding cures.

Many diseases, like cystic fibrosis, are hereditary diseases, meaning they are passed on from parent to offspring.

By looking at the DNA of an individual, doctors can determine what the disease is or how susceptible a person or their children are to having a particular disease. Doctors also study how cells with damaged DNA multiply to help them find cures or treatments for diseases such as cancer and tumors.

But knowledge of DNA is not just used in humans. Food scientists use DNA information to improve crops and develop new food sources.

Plant breeders select plants that produce high yields of food, are resistant to pests, and tolerate environmental stresses better than similar plant varieties.

This is especially important in areas that have poor growing conditions and/or the area has a large population to feed. However, there has been growing debate on whether or not these genetically modified food sources are safe and healthy for human consumption

DNA Science Project

Build a DNA Model

To help further understand how DNA is structured, build a model of it. This is a simplified model of DNA, but it will still give you the general idea of how the sugars, phosphate groups, and bases all connect together to make the famous double helix shape of DNA. You can make a model out of a variety of materials. Here’s how you can do it with candy.

What You Need:

What You Do:

1. Cut the red and black licorice sticks into one inch strips.

2. Make two equal lengths of licorice strands by threading the pieces of licorice onto the string, alternating the red and black pieces.

3. Gather together four different colors of gummy bears, the marshmallows, and the toothpicks.

4. Pair two colors of the gummy bears together and then pair two other colors together. For example, red and orange gummy pairs could be paired together, and green and yellow ones be paired together.

5. Take a gummy bear and thread it onto the toothpick. Thread the marshmallow onto the toothpick so that it is in the center of the toothpick and next to the gummy bear. Thread the complementary gummy bear onto the toothpick so that it is next to the marshmallow. You should now have a toothpick with a gummy bear-marshmallow-gummy bear centered on it.

6. Repeat step five to make more gummy bear-marshmallow toothpicks, making sure the gummy bears are matched with their complementary colors. Make as many of these toothpicks as you have red pieces on one of your licorice strands.

7. Take one strand of licorice and start attaching the gummy bear-marshmallow toothpicks to it, connecting one of these toothpicks at each of the red pieces on the strand. Then, take the second licorice strand and connect it to the other side of the toothpicks. Again, connect the toothpicks to the red pieces of licorice. You should end up with a ‘ladder’ with the red and black licorice stands making the sides of the ladder and the gummy bear-marshmallow toothpicks making the rungs of the ladder.

8. Hold your candy ladder up and turn the top counterclockwise to add twists to the ladder.

What Happened:

You have just made a candy model of a strand of DNA. The red licorice represents the sugar deoxyribose, the black licorice represents the phosphate groups, and together they represent the sugar-phosphate backbone of DNA.

The gummy bears represent the bases that make the code of DNA. The four different colors are used to represent the four different bases found in DNA: adenine (A), thymine (T), guanine (G), and cytosine (C). It doesn’t really matter in your model how much of a base you use or where it is placed in the strand, but it is important that bases are paired up correctly: A with T and G with C. (In real DNA the order does matter as that determines what type of organism it is and how functional it will be.)

The marshmallow in between the gummy bears represents the hydrogen bonds connecting the bases. This is the point at which the DNA strands break apart during replication and where the new strand connects to the original strand.

Twisting the ladder at the top in a counterclockwise direction gives the DNA model its true shape: a right-handed double helix.