Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Alevel Biology [AS] > AS-Biological molecules > Flashcards

AS-Biological molecules Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Which bases are pyramidines?

A

Cytosine and Thymine

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

Which bases are purines?

A

-Pure Silver-Ag
-Adenine and Guanine.

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

What is the 5’ end of a DNA strand?”

A

-5 carbon of deoxyribose unattached to another nucleotide

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

“What is the 3’ end of a DNA molecule?”

A

-The end where the 3 carbon of deoxyribose is unattached to another nucleotide.

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

What is the difference between purines and pyramidines?

A

-Pyramidines - one nitrogenous ring (one point of pyramid)
-Purines - two nitrogenous rings

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

What is the advantage of purines binding with pyamidines?

A

-even molecule width
-more stable

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

What does DNA strands being anti-parallel mean, and what is the advantage of this?

A

-upside down relative to one another
-5’ end of one strand and 3’ end of other strand on the same side of the double helix
-bases in close proximity
-more stable

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

What does DNA strands being anti-parallel mean, and what is the advantage of this?

A

-upside down relative to one another
-5’ end of one strand and 3’ end of other strand on the same side of the double helix
-bases in close proximity - more stable

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

What are Monomers?

A

Small basic molecular units that join together to form a polymer

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

What are polymers?

A

Large complex molecules composed of long chains of monomers joined together

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

Examples of monomers

A

monosaccharides, amino acids and nucleotides

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

Examples of polymers

A

Carbohydrates, proteins and nucleic acids

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

How many types of glucose are there?

A

2

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

What are the names of the types of glucose?

A

Alpha-glucose and beta-glucose

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

Structure of Alpha Glucose

A

Hydrogen to the right of ring is in the ‘attic’

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

Structure of Beta glucose

A

Hydrogen to the right of ring is in the ‘basement’

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

What are alpha and beta glucose relative to glucose?

A

Isomers of gluose

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

What are Isomers?

A

Compounds with a single chemical formula but different forms

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

What is a condensation reaction?

A

When 2 molecules join together with the formation of a new chemical bond, releasing a water molecule

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

Condensation reactions join which molecules?

A

Monosaccharides

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

What type of chemical bond forms between 2 monosaccharides?

A

Glycosidic

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

What is formed when 2 monosaccharides join together?

A

Disaccharide

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

Which 2 molecules make maltose?

A

Alpha glucose and alpha glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is sucrose made from?

A

Alpha glucose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which 2 molecules make lactose?

A

Alpha glucose and galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a hydrolysis reaction?

A

When 2 molecules are broken apart using a water molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is broken down by hydrolysis to form monosaccharides?

A

Carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Benedict’s Test for Reducing Sugars [step1]

A

Add Benedict’s reagent to a sample and add it to a water bath which is boiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Benedict’s Test for Reducing Sugars [step2]

A

-If the test is positive, it will form a coloured precipitate
-if it’s negative, it’ll stay blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Benedict’s Test for Non-Reducing Sugars [step1]

A

-Get a new sample of the test solution,
-add DILUTE HCl
-heat it in a hot water bath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Benedict’s Test for Non-Reducing Sugars [step2]

A

Neutralise the solution with sodium hydrogencarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Benedict’s Test for Non-Reducing Sugars [step3]

A

Carry out the Benedict’s test as normal
positive result= blue to brick red precipitate colour change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is a Polysaccharide?

A

Formed when more than 2 monosaccharides are joined together by condensation reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Function of Starch

A

Energy Store

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What makes up starch?

A

Amylose and amylopectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Structure of amylose

A

-Long, unbranched chain of alpha-glucose
-has a coiled structure
-making it compact and good for storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Structure of amylopectin

A

-Long, branched chain of alpha-glucose
-side branches allow the enzymes that break the molecule down to access the bonds easily
-meaning glucose can be released quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Features of starch

A

-Insoluble in water
-doesn’t affect water potential so water doesn’t enter the cell, which would make them swell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

The iodine test

A

-Add iodine dissolved in potassium iodide solution to the test sample.
-If starch is present, sample turns from yellow to blue black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What do animals store glucose as?

A

Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What structure is glycogen similar to?

A

Amylopectin, except it has more side branches, meaning stored glucose can released quickly, very compact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is a major component of cell walls in plants?

A

Cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Structure of cellulose

A

Long unbranched chains of beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is formed when beta glucose molecules bond?

A

Straight cellulose chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Advantage of cellulose chains

A

They’re linked together by hydrogen bonds to form microfibrils, providing structural support for cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Structure of a triglyceride

A

1 glycerol and 3 fatty acid chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are triglyceride tails made of?

A

Hydrocarbons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Are the triglyceride tails hydrophobic or hydrophilic?

A

Hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Are lipids soluble or insoluble in water?

A

Insoluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What’s the basic structure of a fatty acid?

A

O
||
C
/ \
OH R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Triglycerides are formed by what type of reaction?

A

Condensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is a saturated fatty acid?

A

A fatty acid with no double bonds between the carbon atoms

52
Q

What is an unsaturated fatty acid?

A

A fatty acid with at least one double bond between the carbon atoms

53
Q

What’s the difference between a triglyceride and a phospholipid?

A

A triglyceride has 3 fatty acid tails. A phospholipid has 2 fatty acid tails and a phosphate group attached to the glycerol

54
Q

Is the phosphate group hydrophilic or hydrophobic?

A

Hydrophilic

55
Q

Triglycerides are used as what?

A

Energy storage molecules

56
Q

What do the hydrocarbon tails of triglycerides contain which is useful for us?

A

Chemical energy

57
Q

Lipids contain how much more energy than carbohydrates?

A

Double

58
Q

Are triglycerides insoluble or soluble?

A

Insoluble, don’t affect water potential

59
Q

How do triglycerides act in cells?

A

They clump together as insoluble droplets, the tails face inwards and the heads face out

60
Q

What do phospholipids do?

A

Make up the bilayer of cell membranes, meaning they control what enters and leaves the cell

61
Q

What do phospholipids form?

A

A double layer, heads outside and tails inside, forming a barrier against water soluble substances

62
Q

How do you do the emulsion test?

A

Shake the test substance with ethanol for a minute so it dissolves and pour the solution in water. Any lipid will show as a milky emulsion

63
Q

What are the monomers of protein?

A

Amino acids

64
Q

How is a polypeptide formed?

A

Formed by more than 2 amino acids join together

65
Q

How are proteins made up?

A

Made up of one or more polypeptides

66
Q

Structure of amino acids

A

Carbon bonded to a hydrogen, amino group, R-group and Carboxyl

67
Q

How many amino acids do all living things have?

A

20

68
Q

What is the name of the bonds formed between 2 amino acids?

A

Peptide bond

69
Q

Protein Structure: Primary Structure

A

Sequence of amino acids in the polypeptide chain

70
Q

Protein Structure: Secondary Structure

A

Hydrogen bonds form between the amino acids in the chain, making it coil into an alpha helix or a beta pleated sheet

71
Q

Protein Structure: Tertiary Structure

A

The coiled or folded chain is coiled further, more hydrogen and ionic bonds form.

72
Q

When do disulfide bridges form?

A

Whenever 2 molecules of cysteine come close together

73
Q

Protein Structure: Quaternary Structure

A

Made of several different polypeptide chains, held together by different bonds

74
Q

How do you do the biuret test?

A

-Make the solution alkaline by adding sodium hydroxide solution
-Add copper(II) sulfate solution
-If protein is present, the solution colour changes from blue to purple

75
Q

What are enzymes?

A

Biological catalysts

76
Q

What do enzymes do?

A

They catalyse metabolic reactions at both a cellular level and across the whole organism

77
Q

What can enzymes affect?

A

Structures in an organism (such as collagen production) and functions (such as respiration)

78
Q

What makes each enzyme different?

A

Their active site, which has a specific shape

79
Q

How are enzymes specific?

A

Their tertiary structure

80
Q

How do enzymes speed up a reaction?`

A

If the substrate is being joined, the substrates being attached to the enzyme brings them closer together, reducing any repulsion significantly

If the enzyme is catalyzing a breakdown reaction, fitting into the active site puts strain on the bonds in the substrate, allowing the molecule to break up more easily

81
Q

What is the induced fit model?

A

Where the substrate fits into the enzyme, then the enzyme changes it’s shape slightly to lock the substrate even tighter to itself

82
Q

What is it called when an enzyme and a substrate are joined together?

A

Enzyme-substrate complex

83
Q

What determines the primary structure of a protein?

A

A gene

84
Q

How does pH affect enzyme activity?

A

=All enzymes have an optimum pH (usually 7)
-Above and below the optimum temperature messes up the ionic and hydrogen bonds that hold the tertiary structure in place
-denaturing the enzymes

85
Q

How does enzyme concentration affect enzyme activity?

A

-The more enzyme molecules there are, the more likely there are to be collisions between enzyme and substrate molecules
-forming more enzyme-substrate complexes

86
Q

How can enzyme activity be inhibited by competitive inhibitors?

A

Competitive inhibitor molecules have a similar shape to substrate molecules
-so will compete with the substrate to bind with the enzyme and block the active site.
-The higher the competitive inhibitor concentration, the more active sites are filled and less enzyme-substrate complexes are formed

87
Q

How can enzyme activity be inhibited by non competitive inhibitors?

A

-Non-competitive inhibitors bind to the enzyme away from its active site
-causing the active site to change shape so substrate molecules can’t bind to the enzyme

88
Q

Nucleotide structure (DNA)

A

Phosphate group, deoxyibose (pentose sugar) and a organic nitrogenous base

89
Q

polynucleotide

A

repeating units of a nuclotide

90
Q

What is the general structure of monosaccrides?

A

(CH20)n

91
Q

What does DNA strands being anti-parallel mean, and what is the advantage of this?

A

-upside down relative to one another
-5’ end of one strand and 3’ end of other strand on the same side of the double helix
-bases in close proximity - more stable

92
Q

Describe DNA replication.

A
  • DNA helicase breaks H bonds, unwinding helix
    -Each DNA strand used as a template for a new strand
    -Free DNA nucleotides align with complementary base, form H bonds
    -adenine forms 2 H bonds with thymine, cytosine forms 3 H bonds with guanine
    -DNA polymerase forms phosphodiester bonds between nucleotides
    -by condensation reactions
    -forms sugar-phosphate backbone
    -continues along DNA molecule
93
Q

What direction does DNA polymerase act in and why?

A
  • 5’ to 3’ direction of the developing strand specific tertiary structure
    -binding site with specific shape that is
    -only complementary to nucleotide to 3’ end of developing strand
    -5’ end of developing strand has differently shaped nucleotide
94
Q

What is the advantage of DNA replication being semi-conservative?

A

ensures genetic continuity between generations of cells

95
Q

What does semi conservative replication mean?

A

Each stand from the parent DNA molecule acts as a template for the formation of a new complementary stand

96
Q

Recall the semi conservative hypothesis experiment

A

-Use 2 isotopes of nitrogen
-Heavy nitrogen [15N] -light nitrogen [14N]
-bacteria will take up nitrogen from their surroundings into the DNA they make (bases are made from nitrogen)
-The composition of the DNA was analysed using density gradient centifugation
-The bacteria was taken out of the broth and put in a broth containing only light nitrogen and left to replicate
-When spun in centrifuge again where DNA hybrids (of light and heavy nitrogen) settles in the center of the centrifuge

97
Q

Structure of ATP

A

adenine, ribose sugar (pentose sugar) and 3 phosphate groups

98
Q

what is ATP used for?

A

-short term energy storage
-active transport
-phosphorylation of molecules

99
Q

ATP properties

A

-small and water soluble (can be easilt transported)
-provides energy for metabolic reactions

100
Q

importance of water in Biology

A

-liquid medium (habitat for aquatic organisms)
-metabolite (used in hydrolysis and condensation reactions)
-High specific heat capacity (keeps aquatic/ cellular environments stable)
-Good solvent and transport medium
-good reaction medium
-impressionable (provides structural support in plants)
-penetrateable (light can pass through it)
-transparent (aquatic plants can photosynthesis)

101
Q

How do water molecules attract to eachother?

A

-oxygen slightly negatively charged
-hydrogen slightly positively charged
-attracts to other water molecules

102
Q

Where do ions occur?

A

in solution in the cytoplasm and body fluids of organisms

103
Q

what is the role of Fe 2+ in hemoglobin?

A

-They bind with oxygen
-allow hemoglobin to load oxygen forming ‘oxyhaemoglobin’

104
Q

what is the role of Fe 2+ in photosynthesis and respiration?

A

-involved in electron transfer chains

105
Q

what are the roles of H+ in PH

A

-Concentration of H+ determines the PH
-More H+ = lower PH
-Fewer H+ = higher PH

106
Q

What are the roles of H+ in enzyme controlled reactions?

A

-maintenance of PH is crucial for metabolic reactions
-change in PH can effect enzyme structure
-abnormal levels of H+ can effect side chains of amino acids and change the secondary/tertiary structure.

107
Q

What are the roles of Na+ in co-transport?

A

-required for the transport of glucose and amino acids across cell-surface membranes (e.g. in the small intestine)
-glucose and amino acids can only enter cells via carrier proteins with Na+

108
Q

What is the role of PO43- in forming phosphate groups?

A

-PO43- attaches to other molecules to form phosphate groups, which are an essential component of DNA, RNA and ATP

109
Q

Are cellulose chains straight or branched?

A

Straight

110
Q

Describe the structure of maltose

A

Two alpha glucose’s’ bonded by a glycosidic bond (oxygen bridge)

111
Q

Adaptations of glycogen

A

-compact ( lots can be stored in a small volume)
-insoluble (doesn’t effect osmosis)
-insoluble (so doesn’t diffuse out of cells)
- branched chains (increase surface area)

  • and provide more ends for enzymes to hydrolyse glycogen faster
  • to release glucose faster
112
Q

How is starch adapted for its function?

A
  • compact helical shape, lots of starch stored in small volume
  • insoluble so osmotically inactive
  • large and insoluble so doesn’t diffuse out of cells
  • branched chains increase surface area
  • provide multiple ends for enzymes to hydrolyse starch
  • to rapidly release glucose
113
Q

What do starch and cellulose have in common?

A
  • C H O
  • hydrogen bonding
  • 1,4 - glycosidic bonds
114
Q

Why is glycogen more highly branched than starch?

A
  • glycogen is stored in animals
  • branching increases surface area and number of ends for enzymes to hydrolyse
  • faster release of glucose
  • to maintain higher metabolic and respiratory rates in animals
115
Q

What are the similarities between phospholipids and triglycerides? (4)

A
  • both contain ester bonds
  • both formed from glycerol
  • both insoluble in water
  • both contain C H and O
115
Q

What are the similarities between phospholipids and triglycerides? (4)

A
  • both contain ester bonds
  • both formed from glycerol
  • both insoluble in water
  • both contain C H and O
116
Q

What is the test for lipids?

A
  • grind with ethanol
  • add water
  • milky white emulsion
117
Q

What determines binding site shape?

A
  • tertiary structure not quarternary structure
118
Q

What is the difference between different amino acids?

A
  • R group varies
119
Q

Why would an enzyme become more effective?

A
  • change in tertiary structure of enzyme
  • change in active site shape
  • successful E-S complexes form more quickly
120
Q

Why would one amino acid substitution have a greater affect than another amino acid substitution?

A
  • change in amino acid charge
  • amino acid involved in hydrogen/ionic/disulfide bond
  • larger effect on tertiary structure
121
Q

What are the key words for enzymes? (5)

A
  • specific
  • complementary
  • only
  • fit
  • substrate
122
Q

What are zymogens?

A
  • inactive form of enzymes
123
Q

What control is used for enzyme experiments?

A
  • boiled enzyme
124
Q

Where does a non-competitive inhibitor bind?

A
  • allosteric site
125
Q

Nucleotide structure (RNA)

A

Phosphate group, ribose (pentose sugar) and organic nitrogenous base

126
Q

Evidence for semi-conservative replication of DNA

A
  1. All organic bases in DNA contain nitrogen
  2. Nitrogen has forms: [14N] &[15N]
  3. Bacteria takes up any nitogen in their surroundings into any new DNA they make
126
Q

Evidence for semi-conservative replication of DNA

A
  1. All organic bases in DNA contain nitrogen
  2. Nitrogen has forms: [14N] &[15N]
  3. Bacteria takes up any nitogen in their surroundings into any new DNA they make

Alevel Biology [AS] (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions