definitions Flashcards

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1
Q

Organic Molecule

A

Contain C and H.

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2
Q

Proteome

A

Complete set of proteins expressed by the organism at a certain point in time.

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3
Q

Primary Structure

A

Linear sequence of amino acids in the polypeptide chain.

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4
Q

Secondary Structure

A

Folding/coiling of regions of the polypeptide chain.

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5
Q

Tertiary Structures

A

Folding/coiling of the entire polypeptide chain, resulting in its 3D structure.

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6
Q

Quaternary Structure

A

2 or more polypeptide chains joined together to form a single functional protein.

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7
Q

Chaperonins

A

Proteins that assist with the folding of other proteins.

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8
Q

Fibrous Proteins

A

Elongated and insoluble.
E.g. Catalase

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9
Q

Globular Proteins

A

Folded and coiled into a spherical tertiary and/or quaternary structure. Generally soluble.
E.g. Collagen

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10
Q

Denaturisation

A

Process of altering hydrogen bonds, disulphide bridges, that create the tertiary structure.
Usually loss of function.

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11
Q

Cofactors

A

Non-biological compounds that assist with protein folding and function.

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12
Q

Condensation Polymerisation

A

Reaction during which nucleotides link together.

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13
Q

Gene

A

Region of DNA that contains information to produce a protein.

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14
Q

Genome

A

Complete set of genes in an organism.

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15
Q

mRNA

A

Carries copy of DNA from nucleus to ribosomes.

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16
Q

rRNA

A

rRNA and proteins make up ribosomes.

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17
Q

tRNA

A

Transfers amino acids from cytoplasm to ribosomes.

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18
Q

Ribosomes

A

Organelles that make proteins based on mRNA instructions.

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19
Q

Codon

A

Triplet of nucleotides.

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20
Q

Degenerate

A

More than 1 codon can code for the same amino acid

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21
Q

RNA Polymerase

A

Synthesises RNA by transcription of genes.

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22
Q

Promoter

A

Binding region for RNA polymerase.

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23
Q

Exons

A

Sections of gene that codes for protein

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24
Q

Introns

A

Sections of gene that does not code for protein.

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25
Q

Transcription

A

Production of mRNA from DNA in nucleus.

Initiation:
Transcription factors join to RNA polymerase.
RNA polymerase recognises it, attaching and unzipping the DNA molecule by breaking hydrogen bonds.
Elongation:
RNA polymerase moves along, creating a transcription bubble. It moves from 3’-5’on the DNA and creates the mRNA prime from the 5’-3’ direction.
Termination:
Transcription ends when RNA polymerase reaches the termination codon and detaches.
The DNA molecule reforms.

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26
Q

RNA Processing

A

5’ cap added to 5’ end.
Poly-A tail added to 3’ end.
Splicing removes introns and joins exons together.

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27
Q

Alternative Splicing

A

mRNA can be spliced in many ways as some exons may be removed.

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28
Q

Translation

A

Codons on mRNA translated into amino acid sequence by ribosomes.
Initiation:
Ribosome attaches to 5’ end of mRNA strand, moving along until it reaches the start codon.
tRNA binds joins to start codon, attaching to complementary bases.
Elongation:
Complementary tRNA molecules adds specific amino acids to the growing polypeptide chain via condensation polymerisation.
Termination:
When stop codon reached, polypeptide chain released into the cytoplasm or rough endoplasmic reticulum.

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29
Q

Regulatory Genes

A

Code for transcription factors that control rate of expression for other genes.

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30
Q

Structural Genes

A

Code for proteins that are not involved in gene regulation.

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31
Q

Operon

A

Unit of DNA, consisting of regulated clusters of related genes.

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32
Q

Enzyme

A

Organic catalysts that increase the rate of metabolic reactions by lowering the activation energy.

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33
Q

Active Site

A

Part of enzyme formed by tertiary folding that interacts with specific substrate to catalyse a specific reaction.

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34
Q

Lock and Key Model

A

Substrate has a complementary shape to active site.

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35
Q

Induced Fit Model

A

Substrate binds to active site and creates a ‘conformational change’ of active site so they fir better.

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36
Q

Catabolic Reactions

A

Substrates broken down and energy released.

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37
Q

Anabolic Reactions

A

Require input of energy to produce larger molecules from smaller substrates.

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38
Q

Reversible Inhibition

A

Bonds between inhibitor and enzyme weak and can be easily broken.

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39
Q

Irreversible Inhibition

A

Bonds between inhibitor and enzyme are strong and can’t be broken.

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40
Q

Competitive Inhibition

A

Shape of inhibitor is complementary to shape of active site, blocking substrate from binding.

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41
Q

Non-competitive Inhibition

A

Inhibitor binds to an allosteric site, changing the shape of the enzyme’s active site.

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42
Q

Coenzymes

A

Non-protein, organic cofactors.

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43
Q

Cytokines

A

involved in communication between immune cells.

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44
Q

Apoptosis

A

Programmed cell death.

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45
Q

Vector

A

Organism that spreads disease to others but is not affected by it.

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46
Q

Virus

A

Highly infectious pathogen that infects living cells and uses the cell’s metabolic machinery to replicate.

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47
Q

Prion

A

Misfolded proteins that have pathogenic properties.

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48
Q

Bacteria

A

Unicellular prokaryotes that can have pathogenic properties.

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49
Q

Antigen

A

Specific group of molecules that can induce an immune response.

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50
Q

Self-Antigen

A

Displayed by cells of organism.

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51
Q

Non-self-Antigen

A

Not displayed by cells of organism.
Foreign material provoking an immune response.

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52
Q

First Line of defence

A

Physical, chemical microbiological barriers that provide innate resistance.

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53
Q

Innate Immune Response

A

Non-specific, fast acting response against pathogens that have entered the organism.

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54
Q

Leukocytes

A

White Blood cells

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55
Q

Phagocytes

A

Leukocytes that engulf and breakdown pathogens via phagocytosis.

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56
Q

Complement Proteins

A

Proteins that circulate in the blood and create pores in pathogen’s membrane, enhancing phagocytosis.

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57
Q

Opsonisation

A

Tagging of antigens, attracting phagocytes to pathogen.

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58
Q

Interferons

A

Cytokines that are produced by host cell infected by virus. Activates nearby cells to increase resistance and create antiviral proteins.

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59
Q

Inflammation

A

Accumulation of fluid, plasma proteins and leukocytes that occurs when tissue is damages or infected.

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60
Q

Fever

A

Increase in body temperature to create unfavourable environment for pathogen.

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61
Q

Adaptive Immunity

A

Specific, slower response against pathogens.
Results in immunological memory.

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62
Q

Immunological Memory

A

Ability to remember antigens after primary exposure to create more effective secondary response upon re infection.

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63
Q

Lymphocytes

A

White Blood Cells that are specific for adaptive immune response.

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64
Q

Humoral Immunity

A

Antibodies produced by b cells secreted into bloodstream.

65
Q

Cell-Mediated Immunity

A

Action of T lymphocytes and phagocytes.

66
Q

Clonal Expansion

A

After clonal selection, specific lymphocyte will proliferate and differentiate.

67
Q

Plasma Cells

A

Specialise in antibody production

68
Q

Memory B Lymphocytes

A

Can divide and give rise to plasma cells upon secondary exposure to pathogen.

69
Q

Antibody/Immunoglobin

A

Protein produced by plasma cells as part of the humoral immune response

70
Q

Neutralisation

A

Binding to pathogens and toxins to inhibit their action.

71
Q

Agglutination

A

Bind to antigens, forming inactivated clumps that enhance phagocytosis.

72
Q

T helper Cells

A

Promote inflammation and activates B cells and macrophages.

73
Q

Cytotoxic T cells

A

Recognise/kill foreign/infected host cells by releasing perforins, which lyses cell, or initiates apoptosis.

74
Q

Antigen-Presenting Cells

A

Cells that have specialised function to display antigens on MHC class-II proteins.

75
Q

MHC-I

A

Communicate with cytotoxic t cells about proteins being produced in each cell.
Located on every nucleated cell

76
Q

MHC-II

A

Only present in APCs.

77
Q

Lymphatic System

A

Network of tubes that drains lymph from body tissues

78
Q

Lymph

A

Fluid in tissues

79
Q

Lymph Nodes

A

Contain lymphocytes that filters the lymph for antigens and pathogens.

80
Q

Active Immunity

A

Protection provided by individual’s own adaptive immune response.

81
Q

Passive Immunity

A

Protection provided through the transfer of antibodies produced by another organism.

82
Q

Attenuated Vaccines (Viruses)

A

Vaccines that contain microbes that has been weakened.

83
Q

Inactivated Vaccines (Bacteria)

A

Contain microbes that have been inactivated.
Requires booster shots.

84
Q

Subunit Vaccines

A

Vaccines that do not contain live microbes.
E.g. only antigens injected.
Require multiple doses.

85
Q

Toxoid Vaccines

A

Use toxins to stimulate response.

86
Q

Herd Immunity

A

Phenomenon in which a sufficient number of people in a population need to be vaccinated in order to significantly reduce the chances of the disease spreading throughout the population.
Essential for Protection of those who can’t be vaccinated.

87
Q

Allergens

A

Non-pathogenic substances that invoke an immune response.

88
Q

Autoimmune Disease

A

When lymphocytes recognise self-antigens as non-self and results in an adaptive immune response directed against them.

89
Q

Antigenic Drift

A

Small mutations in the genes of a virus that leads to changes to surface proteins of the virus.

90
Q

Antigenic Shift

A

Major mutations in the genes of a virus that leads to the creation of new subtypes.

91
Q

Chemotherapy

A

Administration of drugs that are cytotoxic to cells that multiply rapidly.

92
Q

Immunotherapy

A

Any treatment that harnesses the immune system of a patient to fight diseases.

93
Q

Monoclonal antibodies

A

Antibodies produced by single clone of B cell in culture to produce a large volume of the clone.

94
Q

Alleles

A

Variations of a gene

95
Q

Species

A

Group of organisms that can interbreed to produce viable and fertile offspring.

96
Q

Gene pool

A

Sum of alleles possessed by individuals in the population.

97
Q

Mutation

A

Changes in the DNA sequence due to chance events.

98
Q

Point Mutation

A

Mutation that adds/removes/changes a single nucleotide in the DNA sequence.

99
Q

1 nucleotide replaced with another.

A

Altered codon still codes for the same amino acid due to degeneracy of genetic code.

100
Q

Missense mutation

A

Altered codon codes for another amino acid.

101
Q

Nonsense mutation

A

Altered codon becomes a stop codon, likely resulting in the production of a truncated protein.

102
Q

Frameshift Mutation

A

One/two nucleotides are added/removed altering sequence of all codons following the insertion/deletion.

103
Q

Block mutation

A

Mutation that affects large segments of chromosomes.

104
Q

Duplication Mutation

A

Replication of section of chromosome.

105
Q

Deletion Mutation

A

Deletion of segment of chromosome

106
Q

Inversion

A

Section of chromosome detaches, rotates 180o, then reattaches.

107
Q

Translocation

A

Segment of chromosome exchanged with another segment.

108
Q

Aneuploidy

A

Presence of abnormal number of a particular chromosome.

109
Q

Polyploidy

A

Condition that results from cells containing more than 2 times the haploid number of chromosomes.

110
Q

Gene Flow

A

Changes in the gene pool of a population due to the migration of individuals

111
Q

Genetic Drift

A

Allele frequencies change randomly overtime due to chance events.

112
Q

Bottleneck Effect

A

When population size is drastically reduced due to a random chance event.

113
Q

Founder effect

A

When a small group of organisms in a population break away from the original population to start their own.

114
Q

Fossils

A

Preserved remains of previously living organisms or their traces.

115
Q

Impression Fossils (Mould fossil)

A

When organism decays, leaving impression of organism’s surface.

116
Q

Cast Fossils

A

Impression fossils that have been filled with foreign material.

117
Q

Mineralised Fossil

A

Impression fossils that have been filled with minerals.

118
Q

Trace Fossil

A

Preserved evidence of organism’s activity or behaviour

119
Q

Transitional Fossils

A

Show features of both ancestral species it originated from and the descendent species that is evolving into.

120
Q

Law of superposition

A

Lowest stratum is the oldest, above strata get progressively younger.

121
Q

Index Fossil

A

A fossil used as a basis of comparison to determine the relative ages of other organisms.
Must be:
Abundant (Big population size)
Widespread (occupies different locations)
Short-lived (If long-lived, leads to greater uncertainty due to organism occupying several strata/layers)
Easily identifiable

122
Q

Carbon-14 Dating

A

Calculating the amount of C-14 in proportion to C-14 in the organism.
Half-life: 5730 years
Only valid for 50,000 years.

123
Q

Argon-Potassium Dating

A

Calculating the amount of Ar-14 in igneous rock near organism.
Half Life: 1.25 billion years
Only valid for more than 500,000 years.

124
Q

Divergent Evolution

A

When a species becomes more phenotypically different due to their exposure to different selection pressures.
Evident by homologous structures

125
Q

Convergent Evolution

A

When dissimilar species become phenotypically similar due to their exposure to similar selection pressures.
Evident by analogous structures.

126
Q

Homologous Structures

A

Features with same morphology but can have different functions.

127
Q

Analogous Structures

A

Features with different morphology but similar structures.

128
Q

Vestigial Structures

A

Structures that had a purpose in the ancestral species by serves little to no purpose in the current descendent species.

129
Q

Molecular Homology

A

Comparing DNA/protein sequences between species to determine their evolutionary relationships.

130
Q

Molecular Clock

A

The usage of the assumption that DNA accumulates mutations at a constant rate to determine approximately how long ago species diverged from a common ancestor.

131
Q

Primate

A

Order including apes and old-world monkeys (no prehensile tail).
Features:
Opposable thumbs
Flattened nails
Stereoscopic vision
Longer gestational period

132
Q

Hominoid

A

Superfamily including all extant apes, their extinct ape ancestors, and gibbons.

133
Q

Hominid

A

Family including all extant apes and their extinct ape ancestors.
Features:
No tails.
Molars have 5 cusps.
Flattened rib cage
Partially/fully erect posture.
Locomotion by brachiation (Climbing from branch to branch), knuckle-walking or bipedalism.

134
Q

Hominin

A

Tribe including all extant members of the homo genus and their extinct, bipedal ancestors.

135
Q

Australopithecus afarensis/africanus

A
  • First bipedal ape/hominin.
  • Evolved in Africa.
136
Q

Homo habilis

A

Made the first tools

137
Q

Homo erectus

A
  • First to use fire
  • First to expand out of Africa
  • More systematic hunting
138
Q

Trends overtime

A
  • Pelvis became wider and more bowl-shaped to support more weight.
  • Larger cranial capacity.
  • Reduced brow ridge.
  • Flatter face
  • Spine became S-shaped
  • Increased Valgus angle between knees to bring knees under body for support.
  • Reduced jaw size due to cooking.
  • Arms got shorter, legs got longer.
  • More centralised Foramen magnum
139
Q

Cultural Evolution

A

Accumulation of knowledge passed onto the next generation by verbal, written or symbolic communication.

140
Q

Multiregional Evolution Model

A

Homo erectus migrated across Africa, Asia and Europe.
Isolation of populations resulted in divergence of gene pools, but some gene flow occurred, resulting in evolution of all groups.

141
Q

Out of Africa Model

A

After Homo erectus left, Homo sapiens evolved and spread, displacing older populations.

142
Q

Polymerases

A

Enzymes that catalyse the formation of polymers of nucleic acids.

143
Q

Polymerase Chain Reaction

A

Process used to amplify (make multiple copies of) target sequences of DNA.

Denaturation: heated to 94oc to break hydrogen bonds
Annealing: cooled to 55oc, to allow primers to bind/anneal to the ends of template strands.
Extension: heated to 72oc, to allow Taq polymerase to create new double-strands from 3’-5’ direction.
Repeat

144
Q

Gel Electrophoresis:

A

Process of separating DNA fragments based on size.
1. Agarose + buffer solution prepared and placed into chamber.
2. Wells made at negative end.
3. DNA samples loaded into wells.
4. DNA ladder is added.
5. Power attached.
6. Small fragments move faster/further, bigger fragments move slower/shorter.
7. Fragments detected by applying a stain.

145
Q

Plasmids

A

Small circular DNA molecules found in bacteria

146
Q

Restriction Enzymes (Endonucleases)

A

Enzymes that cut DNA into smaller fragments at specific recognition/restriction sites.

147
Q

Ligases

A

Group of enzymes that joins fragments of DNA/RNA by forming phosphodiester bonds.

148
Q

Recombinant DNA

A

DNA from 2 different sources joined together.

149
Q

Heat Shock

A

Placing bacterial cells and recombinant plasmids in ice-cold solution, then increasing temperature to disrupt the plasma membrane.

150
Q

Electroporation

A

Mixture of bacterial cells and plasmids subjected to an electric shock to disrupt plasma membrane.

151
Q

DNA Profiling

A

Comparing non-coding sections of DNA of individuals.
Issues:
- Wrongly identifying person.
- Person can be forced to give DNA sample
- Storing DNA may be seen an unethical.

152
Q

Short Tandem Repeats

A

Repeating sequence of 2-6 nucleotides. Number of repeats vary amongst individuals, and so is used during DNA profiling.

153
Q

Genetically Modified Organism

A

Any organism in which DNA has been artificially modified.

154
Q

Transgenic Organism

A

Any organism in which foreign DNA has been introduced into their genome.

155
Q

Emerging Diseases

A

Previously unrecognised diseases that have rapidly increased in incidence and virulence over time.

156
Q

Virulence

A

Ability of the pathogen to cause disease.

157
Q

Epidemic

A

Sudden increase of cases in a population at a particular time.

158
Q

Pandemic

A

Spread of disease over various regions of the world at a given time