Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AQA A LEVEL Biology > Section 1 Biological molecules > Flashcards

Section 1 Biological molecules Flashcards

(54 cards)

Start Studying
1
Q

What are the biological molecules?g

A

Molecules made by living organisms

  • Proteins
  • Lipids
  • ATP
  • DNA
  • Water
  • Inorganic ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the functions of carbohydrates?

A

energy source (glucose in respiration)

energy store (starch in plants, glycogen in animals)

structure (cellulose in cell wall of plants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the building blocks for carbohydrates called?

A

Monosaccharides

Examples:

glucose (alpha and beta), galactose, fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the formula for monosaccharides?

A

C6 H12 O6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the difference between alpha and beta glucose?

A

on Carbon 1, alpha glucose has a OH group on the bottom and beta glucose has a OH group on the top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How are monosaccharides joined together?

A

Condensation reaction (loss of water) between 2 OH groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the definition of a condensation reaction?

A

Condensation reactionA chemical reaction in which two molecules combine to form a larger molecule with the elimination of a small molecule (H2O in biological systems).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Bond in carbohydrate?

A

Glycosidic bond between carbon 1 and 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a dissaccharide?

A

Two monosaccharides bound together via a glycosidic bond.

Examples:
glucose + glucose = maltose
glucose + galactose = lactose glucose + fructose = sucrose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the formula of a dissaccharide?

A

C12 H22 O11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a polymer?

A

A groups of 3 or more monosaccharides bound together by glycosidic bonds.

Examples:

Starch (long chain of alpha glucose) which is energy store in plants

Glycogen (long chain of alpha glucose) which is energy store in animals

Cellulose (long chain of beta glucose) which makes cell wall in plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are polymers separated?

A

Hydrolysis (addition of water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is starch made of and what are their properties?

A

made from Amylose and Amylopectin

Amylose = long straight chain of alpha-glucose which is coiled

Amylopectin = straight chain of alpha-glucose with side branches (1,6-glycosidic bond)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the structure of glycogen?

A

straight chain of alpha-glucose (1,4-glycosidic bond) with side branches (1,6-glycosidic bond)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the properties of STARCH & GLYCOGEN that make it a good energy store

A

Insoluble = do not affect water potential of the cell, do not diffuse out of the cell

Coiled/Branched = compact, more can fit into a cell

Branched/Chained = glucose removed from the end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the structure of cellulose?

A

β-glucose arranged in a straight chain (each alternative β-glucose is rotated 180 degrees) = cellulose straight chain

many cellulose chains are cross linked by hydrogen bonds to form microfibrils

many microfibrils are cross linked to form marcrofibrils

forms structure of cell wall

strong material (prevents plant cell from bursting or shrinking)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the test for starch?

A

Iodine

If present turns blue/black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Test for reducing sugar?

A

Heat with Benedict’s solution

If present turns brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Test for non-reducing sugar?

A

heat with benedicts – no change

therefore, add dilute hydrochloric acid (hydrolyses glycosidic bond)

then add sodium hydrogencarbonate (neutralises solution)

heat with benedict - turns brick red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 2 types or forms of proteins

A

Globular and fibrous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are globular proteins?

A

Soluble proteins with a specific 3D shape

e.g. enzymes, hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are fibrous proteins?

Study These Flashcards
A

strong/insoluble/inflexible material

e.g. collagen and keratin

23
Q

What are the “building blocks” for proteins?

24
Q

Structure of an amino acid

Study These Flashcards
A

central carbon, carboxyl group to the right (COOH), amine group to left (NH2), hydrogen above and R group below

25
How do amino acids differ?
Different R groups
26
How are amino acids joined together?
By condensation reaction between the carboxyl groups causing a peptide bond.
27
Define primary, secondary, tertiary and quaternary.
Primary = sequence of AA, polypeptide chain (held by peptide bonds) Secondary = the primary structure (polypeptide chain) coils to form a helix, held by hydrogen bonds Tertiary = secondary structure folds again to form final 3d shape, held together by hydrogen/ionic/disulfide bonds Quaternary = made of more then one polypeptide chain
28
What is the test for proteins?
Add biuret solution and if present the solution should turn purple
29
What is an enzyme?
A biological catalyst that: Speeds up reaction times Lowers the activation energy
30
What makes an enzyme specific?
It has a specific active site shape which only binds to complementary substrates to form enzyme substrate complexes (ES complexes).
31
What is the lock and key model?
In the lock and key model the active site is rigid and only the exact substrate can bind to the active site to form ES complexes.
32
What is the induced fit model?
The active site changes its shape when the substrate binds so it fits it exactly forming an ES complex.
33
Factors that affect enzyme activity
Enzyme concentration Heat (optimum) Concentration of substrate PH (optimum)
34
What is a competitive inhibitor?
A substance with a similar complementary shape to the substrate making it able to bind to the enzymes active site blocking other substrates from binding.
35
What is a non competitive inhibitor?
A substance that binds to another site on the enzyme OTHER THAN the active site which causes the active site to lose its specific shape and preventing ES complexes.
36
What are the three types of lipids?
Triglycerides Phospholipids Cholesterol
37
What is the structure of a triglyceride?
One glycerol with 3 fatty acids attached
38
What is saturated fat?
Fat that has no double bonds within the R group
39
What is unsaturated fat?
Has carbon double bonds in the R group of the fatty acid.
40
What is the structure of phospholipid?
1 glycerol, 2 fatty acids, 1 phosphate group
41
What are nucleic acids?
Polymers made from nucleotides Examples: DNA and RNA
42
What are the building blocks of DNA?
Adenine with Thymine and Cytosine with Guanine
43
What is the name of the structure of DNA?
Double helix structure
44
What are the properties of the Double helix structure?
Double stranded (more stable) Coil into helix (More compact) Sugar phosphate back bone (Coding for proteins) Complementary base pairing (ensures identical copies)
45
What is the process of DNA replication?
Occurs in inter phase before mitosis and meiosis, also occurs by semi conservative replication
46
Describe Semi conservative DNA replication
DNA helicase breaks hydrogen bonds between the complementary bases Double strands separate leaving two template strands DNA polymerase joins the sugar phosphate backbone of the new strand
47
What is RNA and what are the various types?
Ribo Nucleic Acid 2 types= mRNA and tRNA mRNA is a messenger RNA tRNA is a transfer RNA
48
What is ATP?
Adenosine triphosphate
49
What is the structure of ATP?
Made from 1 adenosine and 3 phosphates Formation: ADP + Pi= ATP
50
What makes ATP an effective energy deliverer?
``` Immediate source (only one bond needs to be broken) Manageable source (small amount of energy released) ```
51
Uses of ATP
``` Protein synthesis Organelle synthesis DNA replication Cell division (mitosis) Active transport Metabolic reactions Movement Maintaining temperature (Homeostasis) ```
52
Roles of water in Biology?
``` Found in living organisms in: Cytoplasm Xylem/phloem Tissue fluid and blood Also acts as a habitat for some living organisms. ```
53
Properties of water
Water molecules (H20) are dipolar
54
What are inorganic ions?
Salts/minerals Inorganic meaning not containing carbon Example: Sodium ions and chloride ions

AQA A LEVEL Biology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions