Brainscape's Knowledge GenomeTM

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


See full index

Biology AS1 Knowledge Organiser > Biological Molecules > Flashcards

Biological Molecules Flashcards

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

What is the difference between organic and inorganic compounds?

A

Organic compounds are the complex, carbon-containing compounds (carbohydrates, fats, proteins, nucleus acids)
Inorganic compounds are simpler and smaller (water, ions, bases)

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

What is a polar molecule?

A

A molecule that carries charge

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

Why is water referred to as being a dipole?

A

Water has 2 areas of opposite charge within its structure
(two positive hydrogen atoms and one negative oxygen atom)

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

What makes water molecules cohesive?

A

Hydrogen bonds form between the positive hydrogens and the negative oxygens of neighbouring water molecules

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

What compound do calcium ions (Ca2+) form in cell walls?

A

Calcium pectate

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

What are iron ions (Fe2+) needed for making?

A

Haemoglobin in the blood, enzymes and cytochromes (electron transfer agents)

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

What is phosphate (PO4 2-) needed for?

A

Making ATP, phospholipids, proteins and nucleus acids

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

What is nitrate (NO3 2-) needed for?

A

Nitrogen from nitrate is needed for making amino acids which are then used to form proteins, such as enzymes, nucleic acids and chlorophyll

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

What compound is Magnesium (Mg2+) used to make?

A

Chlorophyll

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

What is a buffer?

A

A compound that acts in such a way to resist changes in pH (due to adding or removing acid or alkali)

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

Name two buffers

A

Sodium/Potassium hydrogen carbonate
Albumen

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

What elements do carbohydrates contain?

A

Carbon, Hydrogen and Oxygen

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

Name the 3 groups on carbohydrates

A

Monosaccharides, Disaccharides and Polysaccharides

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

What are monosaccharides?

A

The basic carbohydrate monomers. They are classified depending on the number of carbon atoms present in their structure.
Biologically important monosaccharides are triose, pentose and hexose sugars

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

What are isomers? Give an example

A

Isomers are molecules with the same molecular formulae but different structural formulae
Eg: glucose and fructose

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

What is the difference between alpha and beta glucose?

A

The hydroxyl group (-OH) in B-glucose is positioned downwards on the Carbon-1 atom whereas in a-glucose the hydroxyl group (-OH) is positioned upwards on carbon-1

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

What are disaccharides?

A

Double carbohydrates formed from two monosaccharide monomers combined by a condensation reaction. Glycosidic bonds form between the monosaccharides

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

What is a condensation reaction?

A

A condensation reaction involves the removal of water and is the reaction involved when smaller molecules COMBINE to make larger ones

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

What is a hydrolysis reaction?

A

A hydrolysis reaction involves the addition of water and is the reaction involved when larger compounds are BROKEN DOWN into smaller ones

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

What bond is formed between monosaccharide subunits when forming a disaccharide or polysaccharide?

A

A glycosidic bond
Eg: the bond formed when two a-glucose molecules combining is called a 1,4 glycosidic bond.

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

What do the numbers correlate to in a glycosidic bond?

A

The carbon atoms that the bond is formed between

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

What disaccharide is formed when a-glucose and a-glucose combine?

A

Maltose

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

What disaccharide is formed when a-glucose and fructose combine?

A

Sucrose

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

What disaccharide is formed when a-glucose and galactose combine?

A

Lactose

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

What are polysaccharides?

A

Complex carbohydrate which often form very long chains. They are formed through condensation reactions joining a large number of monomers together. Glycosidic bonds link the monosaccharides to form the long chains

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

What is the polysaccharide starch formed from?

A

Starch is made from chains of alpha glucose. There are two types of chains, amylose and amylopectin.

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

Describe amylose

A

Alpha-glucose molecules are linked by 1,4 glycosidic bonds. These chains are coiled to form a spiral. The spirals are held in place by hydrogen bonds. Amylose is an unbranched chain

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

Describe amylopectin

A

Alpha-glucose is linked by 1,4 glycosidic bonds and also 1,6 glycosidic bonds. These form spirals and side branches. The branches may occur as one branch every ten glucose molecule.

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

What makes starch such a good storage molecule in plants?

A

• The molecules of both amylose and amylopectin are very compact. Therefore a large number of glucose is stored in a small space
• Being insoluble, it will not affect the water potential of the cell
• The branched nature of amylopectin creates many terminal ends that are easily hydrolysed
• The large molecule will not easily pass through the cell membrane

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

What is the carbohydrate glycogen made from?

A

Long branched chains of alpha glucose with a mixture of 1,4 and 1,6 glycosidic bonds.
Glycogen is more branched than starch

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

What makes glycogen a good storage molecule in animals and fungi?

A

• It is compact as the shorter, more branched molecules allows it to be packed into granules
• It is insoluble so it will not affect the water potential of the cell
• There are many terminal ends for faster hydrolysis

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

Where is glycogen found?

A

Glycogen is found as granules in liver and muscle cells.

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

Where is starch found?

A

Starch is found as grains in the chloroplasts of plant cells.

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

What is cellulose made from?

A

Cellulose is made from long, straight chains of beta-glucose which are joined by 1,4 glycosidic bonds.
Adjacent chains are held in place by cross-linkages of hydrogen bonds

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

Cellulose is structurally important in plant cell walls. Why?

A

It has high tensile strength due to the cross-links formed by hydrogen bonds. It is also strong due to the beta-glucose molecules forming long, straight chains making it a fibrous molecule

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

What elements are lipids made of?

A

Carbon, Hydrogen and Oxygen
Less oxygen and more hydrogen than carbohydrates

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

What are the main types of lipids?

A

Triglycerides and phospholipids
Lipids also include waxes and steroids

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

How are triglycerides formed?

A

They are formed from one glycerol molecule and three fatty acids. These combine by condensation reactions

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

What type of bond is found in triglycerides and where is it found?

A

Ester Bonds which are formed between the hydroxyl (-OH) and carboxyl (-COOH) groups of the 3 fatty acid chains

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

What are the main jobs of triglycerides?

A

• They act as energy stores and release more energy per unit mass than carbohydrates would
• Insulation as they are non-conductive.
• The sub-cutaneous fat layer beneath the skin acts to protect the major organs

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

How is energy released from triglycerides?

A

Hydrolysis occurs during digestion, breaking the ester bonds and releasing energy

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

What is a saturated fatty acid?

A

Saturated fatty acids contain the maximum number of hydrogen atoms and therefore have no C=C double bonds

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

What is an unsaturated fatty acid?

A

Unsaturated fatty acids do not have the maximum number of hydrogen atoms and do contain C=C double bonds

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

What are polyunsaturated fats?

A

Polyunsaturated days have more than one C=C double bond

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

What is the difference between fats and oils?

A

Fats are solid at room temperature and are often made from saturated fatty acids.
Oils are liquid at room temperature and are often made from unsaturated fatty acids

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

Describe the structure of a phospholipid

A

Phospholipids are made from one glycerol molecule attached to 2 fatty acids and a phosphate molecule.

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

Explain the properties of a phospholipid

A

The phosphate-glycerol head of the phospholipid is hydrophilic, meaning it is attracted to water as it is polar.
The fatty acid tails of the phospholipid are hydrophobic and repels water as it is non-polar

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

What is the importance of phospholipids in the body?

A

They form the phospholipid bilayer which is what cell membranes are made from
They are found in the lungs as surfactant which prevents the lungs collapsing due to the surface tension of water molecules coating the alveoli

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

What different ways can phospholipids arrange themselves?

A

On the surface of water they form a monolayer
When forming cell membranes they form a bilayer
When submerged in water they form micelles

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

What elements are proteins made from?

A

Carbon, Hydrogen, Oxygen, Nitrogen and often sulphur and phosphorus

51
Q

What are the various roles of proteins?

A

Biochemically important as enzymes, hormones, antibodies and buffers.
Structurally important as membranes, hair, muscle, fibres, nails, bones, connective tissue.
Under the conditions of starvation the body uses proteins for energy

52
Q

What is the monomer of proteins? How many unique types are there

A

Amino acids, there are 20 different types of amino acid

53
Q

What are proteins composed of? What is their structure

A

Polymers composed of amino acids.
Amino acid (-NH2) at 1 end + carboxyl group (-COOH) at other end. Different R-group (where sulphur might be)

54
Q

What are long chains of amino acids called?

A

Polypeptides

55
Q

How are amino acid sub-units combined to form a protein

A

Amino acids are combined through condensation reactions (the removal of water). Peptide bonds form between the OH in the carboxyl (-COOH) group and the H in the amino group (-NH2). This forms long chains of polypeptides which then form a protein.

56
Q

What is the importance of the R group in an amino acid?

A

The R groups determine the role and properties of the polypeptide.
This includes its solubility, it’s ability to work as a buffer, it’s enzymatic abilities, the bonds it can form etc

57
Q

What is a dipeptide and how is it formed?

A

A dipeptide is formed when two amino acids combine through condensation reactions and the formation of a peptide bond

58
Q

What is the difference between a polypeptide and a protein?

A

A polypeptide is formed when up to 100 amino acids combine through condensation reactions to form a long chain.
A protein consists of one or more of these chains which are then folded, branched or cross-linked

59
Q

What does the primary structure of a protein mean?

A

The primary structure is the sequence of the amino acids which are joined together by peptide bonds

60
Q

What does the secondary structure of a protein mean?

A

This is the way in which the chain of amino acids folds or turns on itself to make patterns. These folds come from hydrogen bonds forming between the negative (-OH) in the carboxyl group and the positive (-H) in the amino group of the amino acids. These patterns are namely alpha helixes and beta pleated sheets

61
Q

Describe the alpha helices

A

The alpha helix consist of twists and turns in the chain of amino acids which are held in place by hydrogen bonds at regular intervals, forming a spiral

62
Q

Describe beta pleated sheets

A

Beta pleated sheets are more rigid and less flexible configurations.
They are formed by the anti-parallel chains of adjacent amino acids held in place by hydrogen bonds

63
Q

What does the tertiary structure of a protein mean?

A

This involves the further folding a secondary protein. This additional folding provides the protein with its unique 3-D shape and a range of bonds between the R-groups of amino acids in the chain.

64
Q

What bonds are present in a tertiary structure of a protein?

A

Relatively weak Hydrogen bonds
Ionic bonds are formed between the amino and carboxyl groups. These can be damaged by changes in pH
Disulphide bonds are covalent bonds formed between R-groups of sulfur-containing amino acids
Hydrophobic Interactions involving the amino acids with hydrophobic R-groups which tend to influence the tertiary structure

65
Q

What does the quaternary structure of a protein mean?

A

This organisation only exists if there id more than one polypeptide chain present. They may contain non-protein prosthetic groups

66
Q

What is the importance of non-protein components (prosthetic groups) in a quaternary structure

A

These are integral in the protein’s function

67
Q

Give examples of conjugated proteins?

A

A conjugated protein is a protein that contains a prosthetic group.

Glycoproteins, which are important in membrane structure. A carbohydrate is attached to the protein
Haemoglobin, which consists of four polypeptide chains. These are attached to an iron-rich haem group

68
Q

What are the two main types of proteins?

A

Fibrous proteins and globular proteins

69
Q

Describe fibrous proteins

A

Fibrous proteins consist of polypeptide chains arranged to form long fibres of sheets. The parallel chains are cross-linked to form strong stable molecules. Often have structural function. Fibrous proteins have high tensile strength

70
Q

Describe globular proteins

A

Globular proteins consist of polypeptide chains folded to give a spherical 3-D shape which is very specific

71
Q

Explain how collagen is a fibrous protein

A

Each collagen molecule consists of three identical polypeptide wound round each other and held together by hydrogen bonds.

72
Q

Where is collagen found?

A

Collagen is found in tendons that link muscle to bone. Collagen has high tensile strength and does not stretch when tension is applied

73
Q

Explain how Haemoglobin is a globular AND conjugated protein

A

Haemoglobin is made from 4 polypeptide chains (therefore it is quaternary). These chains are tightly folded giving it a globular shape. Each polypeptide chain is attached to a iron-rich haem group (the prosthetic group). The iron ions in the haem group carry oxygen

74
Q

What is a glycoprotein?

A

A protein which is attached to a carbohydrate. An example would be mucin which is found in the respiratory tract

75
Q

What is a prion?

A

Prions are a particular type of protein found in mammals. They are found in the nervous system and it is thought that they are involved in synaptic transmission

76
Q

What is the difference between a normal prion protein (PrP or PrPc) and a disease-causing prion (PrPSc)?

A

The disease-causing prion protein (PrPSc) has a higher proportion of beta pleated sheets (compared to alpha helices)

77
Q

What happens once the disease-causing form of a prion is present in an organism?

A

It leads to a chain reaction causing the number of other disease-causing prions to increase. Ie the prion protein present progressively becomes more misfolded

78
Q

What are the two key features of disease-causing prion proteins?

A

That they can replicate and that they are infectious

79
Q

Is there an incubation period?

A

The incubation period of a prion disease is between 5 and 20 years

80
Q

What makes the normal PrP prion protein change into the PrPSc prion?

A
  • The normal prion protein can spontaneously adopt the PrPSc form
  • May be genetic and a mutation in the DNA that codes for prion proteins can be passed from parent to offspring
  • Through eating contaminated food
81
Q

What examples of prion diseases are there?

A

• Scrapie which affects sheep
• bovine spongiform encephalopathy (BSE) which affects cattle
• variant Creutzfeldt-Jakob disease (vCJD) which affects humans. This is usually acquired through eating contaminated beef products that contain the PrPSc prion

82
Q

What are the typical effects of prion diseases?

A

They are neurodegenerative spongiform diseases, these impair brain function

83
Q

What brain functionality can be effected by a prion disease?

A

Change in memory and personality,
Impaired co-ordination and behavioural changes
Dementia is common

84
Q

What elements are nucleic acids made from?

A

Carbon, hydrogen, oxygen, nitrogen and phosphorus

85
Q

What are the building blocks of nucleic acids?

A

Nucleic acids and formed from nucleotides which consist of a phosphate group, a pentose sugar and a nitrogenous base. These are combined through condensation reactions

86
Q

What bonds are present between the phosphate group and the pentose sugar? What will this form?

A

Phosphodiester bonds link each nucleotide together. This will form a polynucleotide

87
Q

Name two important nucleic acids

A

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

88
Q

Name an important nucleotide used in an organism and give its function

A

ATP (Adenosine Triphosphate) supplies and carries energy in cells

89
Q

What are the nitrogenous bases?

A

Adenine, Thymine, Guanine, Cytosine
(Uracil is present in RNA)

90
Q

Describe the structure of DNA

A

DNA is a double helix, composed of two anti-parallel polynucleotide chains joined by hydrogen bonds between their nitrogenous based. The pentose sugar present in DNA is deoxyribose. Phosphate groups are also present, these are linked to the deoxyribose by phosphodiester bonds

91
Q

What is the base pairing in DNA molecules?

A

Adenine pairs with Thymine (2 hydrogen bonds linking)
Guanine pairs with Cytosine (3 hydrogen bonds linking)

92
Q

How many base pairs are there in a complete turn of a helix?

A

10 base pairs

93
Q

What is the role of DNA?

A

DNA is the genetic code of living organisms and is found in all cells (with few exceptions). It regulates the development of living organisms though the control of protein synthesis

94
Q

What is a gene?

A

A sequence of DNA that codes for a polypeptide

95
Q

Describe the structure of RNA

A

RNA is a single stranded and shorter chain. The nucleotides are linked by phosphodiester bonds but the nitrogenous based are Adenine, Uracil, Guanine and Cytosine

96
Q

What are the 3 types of RNA

A

Messenger RNA, Transfer RNA and Ribosomal RNA

97
Q

What is the role of Messenger RNA?

A

Carries the code from the DNA in the nucleus to a ribosome in the cytoplasm where protein synthesis takes place

98
Q

What is the role of Transfer RNA?

A

Carries the amino acids to the mRNA/ribosome where protein synthesis is taking place.

99
Q

What shape is Transfer RNA?

A

It is a single chain folded into a ‘clover leaf’ shape

100
Q

What is the correlation of Transfer RNA and amino acids?

A

There are as many different types of tRNA as there are amino acids. Their structure is similar

101
Q

What is the role of Ribosomal RNA?

A

Made in the nucleolus and forms over half the mass of each ribosome

102
Q

What does DNA Helicase do?

A

This enzyme causes the DNA double helix to unzip by breaking the hydrogen bonds between the bases.

103
Q

What happens after the DNA double helix is ‘unzipped’?

A

Each strand of DNA becomes an original template strand. Free nucleotides join to the template strands in the correct sequence, following base pairing rules. The result is 2 new DNA molecules. One strand in each new molecule is the original template and one is a new DNA strand

104
Q

What does DNA polymerase do?

A

DNA polymerase helps the new complementary DNA strands to form by catalysing the polymerisation of nucleotides to each other via phosphodiester bonds.

105
Q

Why is the process of DNA replicated described as semi-conservative replication

A

Each of the new DNA molecules contains one original template strand and one new DNA stand

106
Q

Who proved the semi-conservative model?

A

Meselson and Stahl

107
Q

Who worked out the structure of DNA?

A

Watson and Crick

108
Q

What did the conservative model theory propose?

A

In this model the original DNA does not unzip but is simply copied to form a new double strand

109
Q

What we’re the radioactive isotopes used in the Meselson-Stahl experiment?

A

N15 and N14

110
Q

Why were these isotopes used?

A

Nitrogen is part of DNA’s structure as it is forms the nitrogenous based

111
Q

GENERATION 1 of this experiment shown what after density-gradient centrifugation?

A

The bacterial DNA was now hybrid DNA. Half was made of N15 and half N14

112
Q

GENERATION 2 of this experiment shown what after density-gradient centrifugation?

A

The ratio was that 50% of DNA is hybrid N14/15 and 50% was only N14

113
Q

What did GENERATION 3 show?

A

A ratio of 3:1 for light (N14) to hybrid

114
Q

What properties does water have?

A

Polar
hydrogen bonds = cohesion
high specific heat
density anomality (ice)

115
Q

What is the importance of water in organisms?

A

Transport medium (cohesion/adhesion),
chemical reactions (photosynthesis), temp control (buffer),
support (Turgidity),
movement (nastic)
reproduction (fertilisation).

116
Q

State the difference between a Fructose and Glucose molecule

A

Fructose has a 5 membered ring and glucose has a 6 membered ring, however, both are hexose sugars.

117
Q

State the general formula of a monosaccharide

A

(C H2 O)n

118
Q

State the general formula of a disaccharide

A

C12 H22 O11

119
Q

What are the properties of globular proteins?

A

Compact, helical + roll, into ball, hydrophobic interactions, water-soluble, less stable than fibrous (metabolic role)

120
Q

State the roles of globular proteins

A

Metabolic role. Enzymes, antibodies + hormones. e.g. haemoglobin.

121
Q

Why would surgical sterilisation of instruments previously used in a surgery of a patient infected with CJD not kill the prions present?

A

Prions are stable and resistant to temperature and radiation.

122
Q

What is a reducing sugar?

A

Sugar that can reduce due to free aldehyde group. More easily broken down.

123
Q

What is the role of DNA Ligase?

A

Joins polynucleotides together.

Biology AS1 Knowledge Organiser (3 decks)

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