BIOLOGY TOPIC 1 NOTES

Question 1

What are the three types of carbohydrates?

Answer 1

• Monosaccharides
• Disaccharides
• Polysaccharides

These types categorize carbohydrates based on the number of sugar units.

Question 2

Define monosaccharides.

Answer 2

Single sugar monomer

Monosaccharides are the simplest form of carbohydrates.

Question 3

What is the difference between alpha and beta glucose?

Answer 3

On the carbon on the right, the H and OH have swapped places

This structural difference affects their properties and functions.

Question 4

What is ribose?

Answer 4

A monosaccharide with 5 carbon atoms

Ribose is a component of RNA.

Question 5

What are the three disaccharides mentioned?

Answer 5

• Maltose
• Sucrose
• Lactose

Each is formed by the condensation of specific monosaccharides.

Question 6

What is glycogen?

Answer 6

Main energy storage for animals

Glycogen is formed by condensation of alpha glucose and has many side branches.

Question 7

What are the two components of starch?

Answer 7

• Amylose
• Amylopectin

Starch is the energy storage polysaccharide in plants.

Question 8

What is the structure of cellulose?

Answer 8

Unbranched chains of beta glucose joined by 1,4 glycosidic bonds

Cellulose provides structural support in plant cell walls.

Question 9

What is the function of glucose?

Answer 9

Main energy source; easily transported in cells

Glucose is a small, soluble monosaccharide.

Question 10

Define lipids.

Answer 10

Biological molecules only soluble in organic solvents

Lipids include fats, oils, and waxes.

Question 11

What are the two types of lipids?

Answer 11

• Saturated lipids
• Unsaturated lipids

Saturated lipids are solid at room temperature, while unsaturated lipids are liquid.

Question 12

What is a triglyceride?

Answer 12

Lipids made up of 1 molecule of glycerol and 3 fatty acids

Triglycerides are formed by ester bonds in a condensation reaction.

Question 13

What are the four structures of proteins?

Answer 13

• Primary structure
• Secondary structure
• Tertiary structure
• Quaternary structure

Each structure level contributes to the protein’s overall shape and function.

Question 14

What is the role of collagen?

Answer 14

Provides structure to bones, cartilage, connective tissue, and tendons

Collagen is a fibrous protein with high tensile strength.

Question 15

What is the function of haemoglobin?

Answer 15

Carries oxygen in blood

Haemoglobin consists of 4 polypeptide chains and contains iron.

Question 16

What are the components of a DNA nucleotide?

Answer 16

• Deoxyribose
• Phosphate group
• Organic base (adenine, cytosine, guanine, thymine)

DNA nucleotides link to form the DNA double helix.

Question 17

What is the genetic code?

Answer 17

Consists of triplet bases called codons

Each codon codes for an amino acid.

Question 18

What is the process of transcription?

Answer 18

DNA is transcribed into mRNA in the nucleus

This process involves complementary base pairing and is catalyzed by RNA polymerase.

Question 19

What is the role of enzymes?

Answer 19

Biological catalysts that increase the rate of chemical reactions

Enzymes lower activation energy and are specific to substrates.

Question 20

What is the induced fit hypothesis?

Answer 20

Enzyme structure is distorted to mold around the substrate

This model explains how enzymes interact with their substrates.

Question 21

What are enzymes?

Answer 21

Biological catalysts that increase the rate of a chemical reaction by lowering activation energy

Enzymes are globular proteins.

Question 22

Where does the substrate bind on an enzyme?

Answer 22

Active site

Enzymes are specific to substrates they bind to.

Question 23

What is the induced fit hypothesis?

Answer 23

The enzyme’s structure is distorted to mold around the substrate when they form a complex

This model explains how enzymes interact with substrates.

Question 24

How does enzyme concentration affect the rate of reaction?

Answer 24

Increases the rate of reaction until substrate concentration becomes limiting

More enzymes provide more active sites for substrates.

Question 25

How does **substrate concentration** affect the rate of reaction?

Answer 25

Increases the rate of reaction until enzyme concentration becomes limiting ## Footnote More substrates lead to more enzyme-substrate complexes.

Question 26

What happens to the rate of reaction at **optimum temperature**?

Answer 26

Increases until the optimum temperature, then decreases due to enzyme denaturation ## Footnote Hydrogen bonds within the protein are broken.

Question 27

What are **inhibitors**?

Answer 27

Substances that prevent the enzyme from binding to the substrate ## Footnote Inhibition can be reversible or irreversible.

Question 28

What is **competitive inhibition**?

Answer 28

An inhibitor competes with the substrate for the active site, reversible by increasing substrate concentration ## Footnote This prevents the substrate from binding.

Question 29

What is **non-competitive inhibition**?

Answer 29

An inhibitor binds to an allosteric site, changing the enzyme's shape and preventing substrate binding ## Footnote This type of inhibition is irreversible.

Question 30

What is **end-product/feedback inhibition**?

Answer 30

The end product of a multi-step reaction acts as an inhibitor to the enzyme catalyzing the initial stage ## Footnote This regulates the reaction pathway.

Question 31

What are the functions of **nitrate ions**?

Answer 31

Required to make DNA and amino acids ## Footnote Essential for plant growth.

Question 32

What are the functions of **calcium ions**?

Answer 32

Required to make calcium pectate and for the middle lamellae in plants ## Footnote Important for plant structure.

Question 33

What are the functions of **phosphate ions**?

Answer 33

Required to make ADP, ATP, DNA, and RNA ## Footnote Vital for energy transfer and genetic material.

Question 34

What are the functions of **magnesium ions**?

Answer 34

Required to produce chlorophyll ## Footnote Essential for photosynthesis.

Question 35

What makes water a **polar molecule**?

Answer 35

Uneven distribution of charges, with oxygen being more electronegative than hydrogen ## Footnote This allows ionic substances like NaCl to dissolve in water.

Question 36

What is the significance of water's **high specific heat capacity**?

Answer 36

A lot of energy is required to change its temperature ## Footnote This helps organisms survive seasonal temperature changes.

Question 37

What is the role of **cohesion** in water?

Answer 37

Hydrogen bonding between adjacent water molecules allows transport in plants ## Footnote Cohesion also contributes to high surface tension.

Question 38

What is the maximum density of water?

Answer 38

At 4°C, meaning ice is less dense than water ## Footnote This property allows ice to float.