CH 4 : Biological Molecules

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Questions and Answers

What role does Vitamin C play in the human body?

Promotes melanin production

Enhances the absorption of iron

Supports the formation of collagen (correct)

Helps in the process of digestion

What condition is caused by a deficiency in Vitamin C?

Anemia

Osteoporosis

Rickets

Scurvy (correct)

Which of the following symptoms is associated with Scurvy?

Frequent headaches

Pain in joints and muscles (correct)

Weakness of bones

Increased body temperature

What is a significant function of Vitamin D?

Promotes calcium absorption Signup and view all the answers

What deficiency can lead to Rickets in children?

Vitamin D deficiency Signup and view all the answers

Which of the following foods is a rich source of Vitamin C?

Citrus fruits Signup and view all the answers

How many bases make up a single code word or triplet on DNA?

3 bases Signup and view all the answers

What is the primary role of vitamins in the body?

Supporting cellular functions and processes Signup and view all the answers

What is the primary role of fats in the human body?

Providing the main source of energy Signup and view all the answers

Which vitamin is crucial for maintaining healthy skin and vision?

Vitamin A Signup and view all the answers

Which deficiency is caused by a lack of Vitamin C?

Scurvy Signup and view all the answers

What is one of the main reasons for the occurrence of scurvy?

Insufficient Vitamin C consumption Signup and view all the answers

What is the primary importance of Vitamin D in the body?

It aids in calcium absorption for bone health Signup and view all the answers

Which condition is primarily associated with Vitamin D deficiency?

Rickets Signup and view all the answers

What can result from a deficiency in dietary fiber?

Constipation and potential colon cancer Signup and view all the answers

What is a key characteristic of vitamin C?

It spoils when food is heated or canned. Signup and view all the answers

How can one test for the presence of vitamin C in lemon juice?

Using DCPIP, which turns colorless when mixed with vitamin C. Signup and view all the answers

What condition is associated with a deficiency in vitamin D during childhood?

Rickets Signup and view all the answers

Why are sailors at risk of developing scurvy?

They rely on stored or canned food. Signup and view all the answers

Which deficiency-related condition occurs in adults lacking sufficient vitamin D?

Osteomalacia Signup and view all the answers

What happens to vitamin C when food is grated or minced?

It is destroyed due to enzymatic activity. Signup and view all the answers

Which food sources are rich in vitamin D?

Fish liver oil and egg yolk Signup and view all the answers

Study Notes

Biological Molecules

Key biological molecules include carbohydrates, fats, and proteins
Large molecules are made from smaller molecules
Starch and glycogen are made from glucose
Cellulose is made from glucose
Proteins are made from amino acids
Fats are made from fatty acids and glycerol

Testing for Biological Molecules

Iodine solution tests for starch (blue-black colour change is positive)
Benedict's solution tests for reducing sugars (orange-red precipitate is positive)
Biuret test tests for proteins (purple-mauve colour change is positive)
DCPIP test tests for vitamin C (colour change from blue to colourless shows a positive test)
Ethanol test tests for fats (cloudiness in ethanol solution and the forming of a clear solution after adding water confirms fats are present)

Carbohydrates

Carbohydrates are a source of energy for respiration
In plants, carbohydrates are stored as starch
In animals, carbohydrates are stored as glycogen
Cellulose is found in plant cell walls
Polysaccharides are insoluble so they don't create an osmotic effect

Proteins

Proteins are essential for growth and tissue repair
Proteins form enzymes and hormones
Proteins are used for protection against diseases (e.g., antibodies and white blood cells)
Proteins form the cell membrane
Amino acids are water soluble
Some proteins are water insoluble (e.g., keratin in hair and nails)
Excess amino acids are deaminated and excreted in humans
Proteins are made up long chains of amino acids joined together

Fats

Fats are an even larger source of energy than carbohydrates
Fats form a part of the cell membrane (often cholesterol)
Fats are stored in the body as a food reserve
Fats insulate the body
Fats form a waterproof layer for skin, fur, feathers
Fats are solid at room temperature (e.g., butter)
Fats are liquid at room temperature (e.g., oils)

Importance of Water

Water is essential for metabolic reactions
It transports digested food
It transports excretory products
It dissolves enzymes and hormones
It's crucial for regulating body temperature (through sweating)
Water is the main component of cytoplasm

Classification of Carbohydrates

Monosaccharides: basic units of carbohydrates like glucose (C₆H₁₂O₆), fructose, galactose
Disaccharides: made from two monosaccharides linked together like maltose, lactose, sucrose (C₁₂H₂₂O₁₁)
Polysaccharides: long chains of monosaccharides like starch, cellulose, glycogen (C₁₂H₂₂O₁₁)_n

Vitamins (Vitamin C)

Found in citrus fruits, tomatoes and vegetables
Important in collagen formation (protein in skin, bones, and blood vessels)
Maintains healthy gums and blood vessels
Sensitive to heat and air, so refrigeration is important
Water-soluble vitamin, so it cannot be stored in the body

Vitamins (Vitamin D)

Found in butter, egg yolks, fish liver oil, and sunlight.
Helps in the absorption of calcium and phosphorus for bone and tooth formation
Essential for bone development and maintenance
Fat-soluble vitamin, so it can be stored in the body (liver)
Exposure to sunlight aids in vitamin D production

Minerals (Iron)

Important for haemoglobin production
Haemoglobin carries oxygen throughout the body
Deficiency causes anaemia (fatigue and shortness of breath)
Sources include red meat, spinach, and liver

Minerals (Calcium)

Necessary for strong bones and teeth
Important for blood clotting
Important for muscle contraction
Deficiency causes weak bones, brittle teeth, and poor blood clotting
Sources include milk, dairy products, and bread

Fibers

Stimulates peristalsis (movement of food in the gut) to prevent constipation
Sources include cereals, grains, bread, and vegetables

DNA

DNA is a double helix made of nucleotides
Nucleotides: composed of a base, sugar, and phosphate group- There are four bases: Adenine (A), Cytosine (C), Guanine (G), and Thymine (T)
The sequence of bases in DNA determines the sequence of amino acids in proteins
DNA carries genetic information that determines traits

How traits are formed

Genes carry codes for proteins' synthesis
Each code word (codon) is made up of 3 bases
Each codon corresponds to a specific amino acid
The order of codons determines the protein's structure and function
Traits are determined by the order of bases in genes which codes for proteins

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Description

This quiz delves into key biological molecules such as carbohydrates, fats, and proteins, highlighting their structures and functions. Additionally, it covers various tests to identify these molecules, including the iodine test for starch and the Biuret test for proteins. Test your knowledge on molecular biology fundamentals!