Unit 2: Biological molecules Flashcards Preview

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Flashcards in Unit 2: Biological molecules Deck (264)
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What is a polymer?

Large molecule made up of many repeating similar monomers covalently bonded together

1

What is a monomer?

A small molecule that is one of the units bonded together to form a polymer

2

What happens in a condensation reaction?

A covalent bond is formed
Water molecule is released
Larger molecule forms by linking smaller ones (anabolic)

3

What happens in a hydrolysis reaction?

A covalent bond is broken
A water molecule is added
Larger molecule broken into a smaller one (catabolic)

4

What chemical groups are essential to survival?

Carbohydrates, proteins, lipids, vitamins and minerals, nucleic acids, water

5

What distinguishes alpha-glucose and beta-glucose?

On A the 1st carbon has the -OH group below
On B the 1st carbon has the -OH group above

Alpha below, Beta above

6

What is the name of the bond formed between 2 alpha-glucose molecules in a condensation reaction?

A 1,4 glycosidic bond

7

What are the 3 types of carbohydrate and what diff entities them?

Monosaccharides-single sugars
Disaccharides-double sugars
Polysaccharides-more than 2 sugars

8

What features are found in monosaccharides?

They are soluble in water, taste sweet and form crystals

9

Monosaccharides are classified according to the number of carbons they have. How are thy named?

3 C=triose
4 C=tetrose
5 C=pentose
6 C=hexose

10

What is amylase?

Long chains of alpha-glucoses formed by repeated condensation reactions

11

What shape do amylase chains form and what properties do they have?

The chains coil into a spring (due to glucose shape and formation of glycosidic bonds)

This makes them compact and insoluble

12

What is starch used for?
What properties does starch have to suit his role?

Carbohydrate storage

Starch is compact, branching, coiled and insoluble
-> large molecule, holds lots of glucose

13

What is amylopectin?

Short 1,4 alpha-glucose branched chains
They branch off amylase

14

What is glycogen?

Animal energy storage, especially abundant in liver and muscle cells

15

What is the difference between starch and glycogen?

Glycogen has shorter amylose and more amylopectin branches, making it more compact than starch

16

How do beta-glucose molecules bond?

They form by a condensation reaction
One beta-glucose has to be flipped 180 degrees so that the -OH groups line up

17

What are cellulose chains?
What features do they have?

They are long chains made up of 1000 beta-glucose molecules
They are stronger than amylose and only found in plants

18

How do microfibrils and macrofibrils form?

Microfibrils form when cellulose molecules form cross links with hydrogen bonds

Macrofibrils form when microfibrils form hydrogen bonds to form large bundles

19

How do macrofibrils form cell walls?

They are embedded in a polysaccharide glue of substances called pectin

20

What features make cellulose good for plant cell walls?

It gives plant strength
The arrangement of macrofibrils allow water movement through cell wall
Wall holds cell turgid-prevent from bursting
Cell walls reinforced with substances to give extra support/ waterproofing
Macrofibrils arrangement allows cll to grow/change shape eg allowing stomata to open and close

21

Why is cellulose difficult to breakdown naturally?

Humans don't have the right enzymes to do so

22

How does cellulose form the fibre component of the human diet?

It provides 'bulk' to food and pushes it through the digestive system

23

What are the functions of proteins?

Structural components eg bone and muscle
Membrane carriers and pores
Enzymes
Many hormones
Anti-bodies
Transport proteins

24

Describe the structure of an amino acid (draw out if possible)

Amino group (NH2) bonded to CHR bonded to an acid group (O=C-OH)

H H O
I I II
N - C - C
I I I
H R OH

25

How do amino acids differ?

They have different -R groups, this is the only thing that changes between amino acids

26

What do plants need to make all the amino acids they need?

Nitrates from the soil

27

What are essential amino acids?

Amino acids that animals cannot build from the bodies materials and MUST form a part of the diet

28

How do amino acids bond?

By a condensation reaction between an-OH group and a -H group. They make a peptide bond (covalent) and form a dipeptide molecule

29

Why can surplus amino acids be toxic?
How are they removed?

Toxic due to amino group
They are removed in deamination of the liver
-amino group converted to urea, later removed as urine