Chapter 3 part 1: Biological molecules 👩‍🔬

Question 1

What are carbohydrates made up of?

Answer 1

• Carbohydrates are made up of carbon (C), hydrogen (H), and oxygen (O).
• The ratio of hydrogen to oxygen atoms is 2:1, meaning there are 2 hydrogen atoms and 1 oxygen atom.
• The general formula for carbohydrates is CH2O*
  (E.g. The formula for glucose is C6H12O6)

Question 2

What are the types of carbohydrates?

Answer 2

1. Single sugars
   - Glucose
   - Fructose
   - Galactose
2. Double sugars
   - Maltose
   - Sucrose
   - Lactose
3. Complex carbohydrates
   - Starch
   - Cellulose
   - Glycogen

Question 3

What are simple sugars?

Answer 3

• Simple sugars are the basic unit of carbohydrates.
• They can pass through cell membranes easily.

Question 4

What are some examples of simple sugars?

Answer 4

• Glucose and fructose are common simple sugars, and they have the same chemical formula, but their atoms are arranged differently, giving them different properties.

Question 5

What are double sugars?

Answer 5

• Double sugars are made up of two single sugars joined together.
• Double sugar can be split into two single sugars with the action of an enzyme.
• When mixed with the enzyme maltase, maltose splits to form two glucose molecules.
  (maltose —(maltase)—> 2 glucose molecules) 🍬

Question 6

What is a complex carbohydrate?

Answer 6

• A complex carbohydrate is made up of many single sugar molecules joined together to make a large molecule.
• Starch is the storage form of carbohydrates in plants.
• Cellulose is found in plant cell walls which protect plants from bursting and damage.
• Glycogen is the storage form of carbohydrates in animals.

Question 7

What is starch?

Answer 7

• Starch is the storage form of carbohydrates in plants.

Question 8

Where is cellulose found in plant parts?

Answer 8

• Cellulose is found in plant cell walls which protect plants from bursting and damage.

Question 9

What is glycogen?

Answer 9

• Glycogen is the storage form of carbohydrates in animals.

Question 10

What are the different types of carbohydrates?

Answer 10

• Single sugar, double sugar, and complex carbohydrate.

Question 11

What are some examples of single sugars?

Answer 11

• Glucose, fructose, and galactose.

Question 12

What is glucose?

Answer 12

• Glucose is a six-carbon compound arranged in a ring structure.
• It comes from the leaves of plants and animals, but in small quantities.

Question 13

What is fructose?

Answer 13

• Fructose is a six-carbon compound arranged in a ring structure.
• It comes from fruits and vegetables, and honey.

Question 14

What is galactose?

Answer 14

• Galactose is a six-carbon compound arranged in a ring structure
• It comes from mammalian milk, fruits and vegetables, and the hydrolysis of glucose.

Question 15

What are some examples of double sugars?

Answer 15

• Maltose, sucrose and lactose.

Question 16

What is maltose?

Answer 16

• Maltose is a reducing sugar.
• It is made out of 2 glucose atoms (glucose x2).
• It comes from germinating grains (e.g. malt), the breakdown of starch, glycogen in animals.

Question 17

What is sucrose?

Answer 17

• Sucrose is a non-reducing sugar.
• It is made out of 1 glucose and 1 fructose atom. (glucose x1 + fructose x1)
• It comes from sugarcane stems, sweet fruits, and storage roots (e.g. Carrots)

Question 18

What is lactose

Answer 18

• Lactose is a non-reducing sugar.
• It is made up of 1 glucose and 1 galactose atom.
• It comes from only mammalian milk.

Question 19

What are some examples of complex carbohydrates?

Answer 19

• Starch, cellulose and, glycogen.

Question 20

What is starch?

Answer 20

• Starch is made up of several thousand glucose molecules arranged in long and straight chains.
• It comes from the storage organs of plants such as potato tubers, and tapioca roots,

Question 21

What is cellulose?

Answer 21

• Cellulose is made up of straight chains of glucose but is linked differently from the starch. **
• It comes from the cell walls of plants.

Question 22

What is glycogen?

Answer 22

• It is made up of chains of glucose that are highly branched.
• It is stored in the liver and muscles of animals.
  OR
• It comes from places that are stored in the liver and muscles of animals.

Question 23

What are the characteristics of starch and glycogen which made them suitable to be storage materials?

Answer 23

• They are insoluble in water, so they do not affect water potential in cells.
• They take up less space than individual glucose molecules as they are COMPACT molecules.
• They are not able to diffuse out of the tiny pores of the cell membrane, as they are large molecules.
  They are easily broken down into glucose when necessary.

Question 24

What are the functions of carbohydrates in animals and plants?

Answer 24

• Carbohydrates function as an energy source
• Allows nectar to be produced in some flowers.
• It is used to form supporting structures such as cellulose cell walls in plants.
• It is used to make lubricants such as mucus.
• It is used for conversion into other organic substances such as amino acids and fats.
• It is used to form nucleic acids such as DNA and RNA.

Question 25

What are fats made out up?

Answer 25

- Fats are made out of carbon, hydrogen, and oxygen. - The ratio of hydrogen to oxygen atoms is much higher in fats than in carbohydrates, - There is no fixed formula for fats. (E.g.) The formula for tristearin is C57H110O6. - Each fat molecule is made from 1 glycerol and 3 fatty acid molecules.

Question 26

What are the different mediums in that fats are insoluble and soluble in?

Answer 26

- Fats are insoluble in water but it is soluble in organic solvents such as chloroforms and ethanol.

Question 27

Where can fats be found in?

Answer 27

- Fats can be found in both animal and plant foods. - Animal sources include fish such as herring and salmon, fatty red meat, and dairy products, such as butter and cheese. - Plant sources include olives, nuts, peas, beans, and seeds of castor and palm.

Question 28

What are the functions of fats?

Answer 28

- Fats function as an energy source and store (for storage). - It is an essential part of cell membranes. (made up of proteins and fats) - It is a solvent for fat-soluble vitamins and hormones. - It is an insulating material to prevent heat loss from the skin. (E.g.) An oily substance secreted by glands in the skin reduces the rate of water evaporation.

Question 29

Do fats have a higher energy value, or a lower energy value compared to carbohydrates?

Answer 29

- Yes. Fats have a higher energy value compared to carbohydrates, and function as a long-term store of energy, especially in animals.

Question 30

What are proteins made out of?

Answer 30

- Proteins are made up of carbon, hydrogen, oxygen and nitrogen. - Sulfur is present in some, but not all proteins.

Question 31

What are amino acid hormones?

Answer 31

- Amino acid hormones is a monomer (a molecule of any class of compounds) that is part of each protein molecule.

Question 32

What is an amino acid made out of? -

Answer 32

- Each amino acid is made out of an amino group (-NH2), a carboxylic acid group (-COOH), and a carbon side chain (R). - The carbon side chain, R, can sometimes contain sulfur. - There are about 20 naturally occurring amino acids, each differing in their R groups.

Question 33

What is the formula for an amino acid?

Answer 33

The general formula for an amino acid: - R-CH (NH 2)-COOH

Question 34

What are (strong) peptide bonds?

Answer 34

- Peptide bonds are formed when amino acids combine in a reaction, thus forming strong peptide bonds.

Question 35

What is a polypeptide?

Answer 35

- A polypeptide is formed when many amino acids combine and react together, thus forming a polypeptide.

Question 36

What happens when one or more polypeptide chain fold together?

Answer 36

- When one or more polypeptide chains fold together to form a complex 3-dimensional protein molecule.

Question 37

What happens when proteins are partially broken down?

Answer 37

- When proteins are partially broken down into polypeptides, it can be completely broken down into amino acids. (proteins—> polypeptide—>amino acids) - However, this may not always happen.

Question 38

What are the factors that affect the 3-dimensional structure?

Answer 38

- The 3-dimensional structure of proteins is affected by exposure to high temperatures or extreme changes in the pH value. - The protein loses its shape and function, and it is said to be denatured.

Question 39

What types of food can proteins be found in?

Answer 39

- Proteins can be found in both animal and plant foods. - Animal sources include milk, eggs, seafood, chicken, and lean meat. -Plant sources include soya beans, nuts, grains, and vegetables.

Question 40

What are the functions of proteins in animals, and plants?

Answer 40

- To make new protoplasm for growth, and repair of worn-out body cells. - To make enzymes. - To make certain hormones. - To form antibodies to fight diseases (bacteria).

Question 41

What is KWASHIORKOR, and what is the cause of it?

Answer 41

- KWASHIORKOR is caused by the insufficient intake of proteins in a child's diet, or protein deficiency, which may lead to KWASHIORKOR (a disease). The symptoms of KWASHIORKOR are: - Scaly and cracked skin - Pot-belly appearance.

Question 42

Why must carbohydrates, proteins and fats be broken down by enzymes during digestion?

Answer 42

- Since carbohydrates, proteins, and fats are too large to pass through the cell surface membranes. Thus, they must be broken down by enzymes during digestion before they can be absorbed by the body.