Biological Molecules (carbs, proteins, lipids, enzymes)

Question 1

What are the three types of chemical found in living things

Answer 1

Carbohydrates
Proteins
Lipids

Question 2

What are the three types of carbohydrates

Answer 2

Monosaccharides
Disaccharides
Polysaccharides

Question 3

Examples and features of monosaccharides

Answer 3

Glucose and fructose

Sweet taste
Soluble in water

Question 4

Examples and features of disaccharides and what they contain

Answer 4

Contains strong covalent bonds between two monosaccharides

Sucrose and lactose

Sweet taste
Soluble in water

Question 5

Examples and features of polysaccharides and what they contain

Answer 5

Contains long chains of monosaccharides held together by strong covalent bonds

Glycogen
Cellulose
Starch

No sweet taste
Insoluble in water

Question 6

What elements of carbohydrates contain

Answer 6

Carbon, hydrogen and oxygen

Question 7

What is glycogen

Answer 7

A polysaccharide used as an energy store for animals

Question 8

What is cellulose

Answer 8

A polysaccharide found in cell walls, cotton, wood and paper

Question 9

What is starch

Answer 9

A polysaccharide contained in pasta, rice, porridge, potatoes

Question 10

What is the test for glucose and what are the results

Answer 10

Benedictus reagent (+ heat)

Positive —> orange/ yellow
Negative —> blue

Question 11

What is the test for starch and what is the result

Answer 11

Iodine

Positive —> blue/ black
Negative —> yellow

Question 12

What are lipids

Answer 12

Chemicals found in living things and are insoluble in water but soluble in solvents such as benzene and petrol

Question 13

Functions of lipids (5)

Answer 13

Source of energy in food
Store of energy in animals
Insulation in the nervous system
Hormones
Thermal insulation against heat loss

Question 14

What are the two components of a lipid molecule

Answer 14

Glycerol and fatty acids

Question 15

What elements do lipids contain

Answer 15

Carbon, hydrogen and oxygen

Question 16

What is the test for lipids how do we carry it out

Answer 16

Emulsion test

Dissolve sample in ethanol
Decant clear layer
Add water and shake
If lipid is present it will turn cloudy

Question 17

What are proteins made it of and which elements are present

Answer 17

Amino acids

Carbon,hydrogen, oxygen, nitrogen, sulfur

Question 18

Examples of food that contain protein

Answer 18

Fish
Beans
Meat
Wheat

Question 19

What is the formation of proteins

Answer 19

Amino acids form long chains held by peptide bonds

The chain is twisted and folded into a shape that allows it to do its function

The whole molecule is a polypeptide

Question 20

What can change the shape/ activity of a protein (2)

Answer 20

Heat (becomes denatured if too hot)

pH

Question 21

What is the most important thing about protein and what does it determine

Answer 21

The shape determines its functions

Question 22

Functions of proteins (5)

Answer 22

Structural
Hormones
Antibodies
Enzymes
Transport

Question 23

What is the test name for protein, what must be added and what is the result

Answer 23

Buret test

Add copper sulphate or dilute NaOH to solution

Positive —> purple/ lilac

Question 24

How many different monomers is there that can be combined to make protein molecules

Answer 24

20

Question 25

What is the monomer is protein

Answer 25

Amino acid

Question 26

What are enzymes made out of

Answer 26

Protein molecules

Question 27

What allows enzymes to carry out their specific function

Answer 27

Their shape and active site

Question 28

What do enzymes do and how do they do it

Answer 28

Speed up chemical reactions by reducing the energy needed of the reaction

Question 29

What is the lock and key principle of how an enzyme works

Answer 29

Substrate enters the enzyme's active site Reaction takes place Products form and leave the active site

Question 30

What are enzymes like after the reaction

Answer 30

Unchanged

Question 31

Why does the rate of reaction decrease after the optimum temperature or pH

Answer 31

The number of enzymes denatured increases the further the temperature/ pH is away from the optimum point until there is no active site

Question 32

What happens when enzymes get too hot

Answer 32

They change shape so they denature and there is a change in active site

Question 33

Which enzyme is excreted by salivary glands, what do they break down and what is their optimum pH

Answer 33

Amylase which breaks down starch | pH 7.4

Question 34

Which enzyme is found in the stomach, what do they break down and what is their optimum pH

Answer 34

Protease which breaks down proteins | pH 2.0

Question 35

Which enzyme is found in the small intestine, what do they break down and what is their optimum pH

Answer 35

Lipase which breaks down lipids pH 7.6

Question 36

What is the effect on enzymes with temperature

Answer 36

The action of the enzymes

Question 37

What is the effect on enzymes with pH

Answer 37

The structure of the enzyme

Question 38

What is an enzyme

Answer 38

A substance made of protein which are produced by living organisms that acts as a catalyst