Structure and functions of living organisms - biological molecules

Question 1

What are the chemical elements present in carbohydrates

Answer 1

Carbon, Hydrogen and Oxygen

Question 2

What are the chemical elements present in proteins

Answer 2

Carbon, Hydrogen, Oxygen and Nitrogen

Question 3

What are the chemical elements present in lipids (fats and oils)

Answer 3

Carbon, Hydrogen and Oxygen

Question 4

What are Proteins made from (small basic unit(s))

Answer 4

Amino acids

Question 5

What are Lipids made from (small basic unit(s))

Answer 5

Fatty acids x3
Glycerol x1

Question 6

What are Carbohydates made from made from (small basic unit(s))

Answer 6

Starch - multiple glucose molecules (+ maltose) (polysaccharide)

Glucose - Is a monomer

Question 7

What is the test for the presence of starch

Answer 7

The Iodine test
- A result varies from orange/brown (no starch) to Blue/Black (high concentration of starch)

Question 8

What is the test for the presence of glucose

Answer 8

Benedicts test (+ heat, normally water bath)
- A result varies from blue (no glucose) to Brick Red (high concentration of glucose)

Question 9

What is the test for the presence of protein

Answer 9

Biuret test
A positive result goes from blue to purple

Question 10

What is the test for the presence of lipids

Answer 10

Ethanol + water
Positive test = white emulsion

Question 11

What is the role of enzymes

Answer 11

They are biological catalysts in metabolic reactions

Question 12

How do temperature changes affect enzymes

Answer 12

An enzymes active site is deformed when the temperature is too high
An enzymes optimal temperature is 37 degrees celcius
as well as:
https://www.bbc.co.uk/bitesize/guides/z88hcj6/revision/2#:~:text=As%20with%20many%20chemical%20reactions,and%20can%20no%20longer%20function.

Question 13

Practical: How can enzyme activity can be affected by changes in temperature

Answer 13

https://www.savemyexams.com/igcse/biology/edexcel/19/revision-notes/2-structure-and-function-in-living-organisms/biological-molecules/2-12-practical-investigating-temperature–enzyme-activity/

Question 14

How can an enzyme’s function be changed by PH

Answer 14

When the PH is too high the active site is deformed and the enzyme becomes denatured
https://www.bbc.co.uk/bitesize/guides/z88hcj6/revision/2#:~:text=As%20with%20many%20chemical%20reactions,and%20can%20no%20longer%20function.

Question 15

Practical Investigate how enzyme activity can be affected by changes in PH

Answer 15

https://igcse-biology-2017.blogspot.com/2017/06/214b-practical-investigate-how-enzyme.html

Question 16

How does an enzyme work

Answer 16

https://www.bbc.co.uk/bitesize/guides/zwnstv4/revision/1#:~:text=Enzyme%20action,An%20enzyme’s%20active%20site

Question 17

What are the specific enzymes for:
1) Carbohydrates
2) Starch
3) Protein
4) Fats (lipids)

Answer 17

1) Carbohydrase
2) Amylase
3) Protease
4) Lipase