Biological Molecules - CARBS

Question 1

What is a polymer?

Answer 1

A large, complex chain of monomers

Question 2

What are monomers?

Answer 2

Small, basic molecular units that can be joined to make polymers

e.g., monosaccharides, amino acids, nucleotides

Question 3

What three elements are carbohydrates made of?

Answer 3

C H O

Clue is in the word:

carbo - carbon

hydr - hydrogen

-ate - oxygen (anything ending in -ate has O in it)

Question 4

Name a hexose sugar

Answer 4

glucose

It has six carbons in each atom

Question 5

What is an isomer - give an example

Answer 5

Isomers have the same molecular formula but are arranged differently.

E.g., alpha and beta glucose molecules

Question 6

Draw a glucose molecule and then check the answer

Answer 6

Question 7

What is a condensation reaction?

Answer 7

When two molecules join together, their reaction gives off water, H₂O

(water - steam - condenses to water on cold glass…)

Question 8

What is the name of the bond that forms when two monosaccharides form?

Answer 8

A glycosidic bond

Question 9

What is a glycoside?

Answer 9

A ring shaped molecule, e.g, glucose

Question 10

Glucose and fructose create which disaccharide?

Answer 10

Sucrose

Question 11

Glucose and galactose create which disaccharide?

Answer 11

Lactose

Question 12

What does hydrolysis do?

Answer 12

Breaks down polymers

hydro - water

This time the separation of the monomers from each other attracts a water molecule to reform the monomers which makes them more chemically stable again.

Question 13

What are reducing sugars?

Answer 13

They donate electrons

They can be detected using the Benedict’s test

Examples: glucose, fructose, maltose

Question 14

What are non-reducing sugars?

How can their presence be detected?

Answer 14

Non-reducing sugars cannot donate electrons, therefore they cannot be oxidised

e.g. sucrose

To test non-reducing sugars, add hydrochloric acid to boiled water; neutralise the acid with sodium hydrogencarbonate then proceed with Benedict’s test.

USEFUL QUICK VIDEO LINK:

Question 15

What is the main energy storage in a plant?

Answer 15

Starch.

Plants store EXCESS GLUCOSE as STARCH.

When energy is needed, the starch is broken back down into glucose.

Question 16

What is starch made up of?

Answer 16

Amylose and amylopectin

amylose = long, unbranched chain of alpha-glucose; it coils like a cylinder making it compact

amylopectin - long branched chain of alpha-glucose; its side branches allow it to be broken down by enzymes so glucose can be easily released.

Question 17

What’s useful about starch?

Answer 17

1. insoluble in water,
2. therefore unaffected by osmosis and hence makes it great for storage (think of wrapping books up in vacuum sealed bags to protect them from damp in humid conditions)
3. also when mixed with water acts as a thickening agent
4. added to food as a replacement for fat (hmm - good idea?)

Question 18

What is the test for starch?

Answer 18

Iodine test

dark, blue-black = starch is present!

Question 19

What is the main energy storage in material in animals?

Answer 19

Glycogen

Animals store excess glucose as glycogen (polysaccharide of alpha glucose)

Glycogen has lots of branches which can be broken off easily by enzymes to release energy quickly.

It’s compact and therefore good for storage.

QUICK CHEESY VIDEO LINK

Question 20

Name three disaccharides found in food

Answer 20

SLM

sucrose

maltose

lactose

Question 21

Which saccharides cause blood sugar swings?

Answer 21

eating monosaccharides rather than complex carbohydrates

Question 22

Which sugar is found in milk?

Answer 22

lactose

Question 23

What process can be used to remove lactose from milk?

Answer 23

Hydrolysis which converts the discharride into monosaccharides glucose and galactose using the enzyme lactase

Question 24

What is cellulose? (3pts)

Answer 24

1. aka ‘dietary fibre’ or a ‘non-starch polysaccharide’
2. up to 10,000 glucose molecules join to form a straight chain
3. it is indigestible in the human gut but helps the movement of material through the intestines

Question 25

What is cholesterol?

Answer 25

A short lipid molecule

Question 26

What is the function of cholesterol? (3 pts)

Answer 26

1. A vital component of cell membranes
2. Formation of bile
3. Formation of sex hormones progesterone and testosterone

Question 27

What are essential fatty acids? Why are they deemed essentail? (3pts)

Answer 27

Fatty acids that the body needs but cannot synthesise.

E.g, deficiency of linoleic acid can cause scaly skin, hair loss and slow wound healing

Fat soluble itamins A,D,E,K can only absorbed with the help of fats