Unit 3 AOS 1 Key Terms Flashcards
1
Q
Define α-helix
A
A type of secondary protien structure in which the polypeptide chain folds into a tight coil
2
Q
Define allele
A
A different version of the same gene (at the same locus) determined by small difference in the DNA sequence of the gene
3
Q
Define alternative splicing
A
A process in which one or more exons are removed with the introns to produce mRNA molecules of different length and sequence
4
Q
Define amino acid
A
a nitrogen-containing compund that is the monomer from which proteins are built
5
Q
Define anticodon
A
The three nucleotides in tRNA that bring to the complementary codon in mRNA according to base-pairing rules, resulting in the addition of a specific amino-acid to the polypeptide chain
6
Q
Define antiparallel
A
Parallel but orientated in the opposite direction
7
Q
Define attenuation
A
A mechanism for reducing expression of the 𝘵𝘳𝘱 operon when trytophan levels are hig, by preventing completion of transcription of the structual genes, not by stopping initiation of transcription by a repressor protein
8
Q
Define β-pleated sheet
A
A type of secondary protein strucure in which segments of the polypeptide chain bond side by side into a flattened assembly
9
Q
Define base pair
A
Two complementary nitrogen bases linked by hydrogen
10
Q
Define biological funtionality
A
The function of a protein
11
Q
Define catalyse
A
To speed up a biochemical equation using an enzyme
12
Q
Define chromosome
A
A thread-like structure made of nucleic acids and proteins that encode genetic information
13
Q
Define cisterna
A
A flattened membrane disc that makes up Golgi apparatus and endoplasmic reticulm
14
Q
Define codon
A
A group of 3 nucleotides in mRNA that specifies an amino acid
15
Q
Define complementary base pairing
A
The linking together of complementary nitrogen basing by hydrogen bonding; A pairs with T ( or U in RNA) and C pairs with G
16
Q
Define condensation polymerisation
A
A reaction in which monomers are linked together into a polymer with the release of a small molecule, such as water, as a by-product
17
Q
Define conformation
A
The proper or functional shape of a protein
18
Q
Define degenerate
A
A property of the genetic code in which most animo acids are encoded by two or more codons
19
Q
Define denature
A
To permanately change the molecular structure of a protein or DNA
20
Q
Define deoxyribonucleic acid (DNA)
A
The information molecule that is the basis of an organism’s genetic material
21
Q
Define DNA polymerase
A
The enzyme that catalyses the bonding of nucleotides to form new strands of DNA
22
Q
Define endoplasmic reticulum
A
An organelle made up of a network of membranous tubules involved in protein synthesis and folding for secretion
23
Q
Define enzyme
A
A specific protein catalyst that increases the rate of a biochemical reaction within the cell by lowering the amount of energy required for the reaction to proceed
24
Q
Define exon
A
A segment of DNA or RNA containing information that codes for a polypeptide or part of a polypeptide
25
Define functional proteomics
The study of how proteins work together in different cells or tissues, or under different circumstances
26
Define gene
A segment of DNA in a chromosome that codes for a polypeptide; comprises the promoter, exons and introns
27
Define gene expression
The process by which the information in a gene is turned into a polypeptide
28
Define gene regulation
The process by which gene expression is switched on or off
29
Define genetic code
The complete set of mRNA codons and the corresponding amino acids they specify
30
Define genome
The complete sequence of DNA in a single (haploid) set of an organism’s chromosomes, including nuclear, mitochondrial and chloroplast DNA
31
Define Golgi apparatus
A collection of membranes that package and store substances into vesicles in preparation for their release from the cell
32
Define histone
A protein that binds and packages DNA in eukaryotic chromosomes
33
Define hydrogen bond
A weak chemical bond between a hydrogen atom on one molecule and a more electronegative element, usually an oxygen or nitrogen atom, on another molecule
34
Define hydrophillic
Describes substances such as polar molecules and ionic compounds that dissolve readily in water
35
Define hydrophobic
Describes substances such as non-polar molecules that are insoluble in water
36
Define inducer
A signalling molecule that switches on expression of a gene
37
Define intron
A segment of DNA within a gene or pre-mRNA that does not code for a polypeptide and interrupts the sequence of a gene
38
Define messenger RNA (mRNA)
RNA copied from DNA that conveys the instructions needed for polypeptide synthesis from the nucleus to the cytoplasm
39
Define non-coding region
DNA that does not encode a protein sequence
40
Define non-template strand
The DNA strand that has the same sequence of nucleotides as the mRNA (except it has T instead if U)
41
Define nucleic acid
A large, linear polymer built from nucleotide monomers bonded together; includes DNA and RNA
42
Define nucleosome
A histone with a length of DNA coiled around it
43
Define nucleotide
The monomer, or building block, of DNA and RNA, consisting of sugar, phosphate and a nitrogen base
44
Define operator
A segment of DNA to which a protein binds, usually to switch iff gene expression
45
Define operon
A group of genes that are expressed as a single unit
46
Define peptide bond
A chemical bond that links two nucleotides in a growing chain
47
Define phosphodiester bond
A chemical bond that links two nucleotides in a growing chain
48
Define plasmid
A small, circular DNA structure independent of the chromosome in prokaryotic cells
49
Define poly-A tail
A chain of 100-200 adenine nucleotides added at the 3’ end of an mRNA strand
50
Define polypeptide
A linear polymer built from amino acid monomers
51
Define polyribosome
A chain of ribosomes formed by attaching to and translating from a single mRNA strand
52
Define pre-mRNA
An unprocessed RNA strand that is transcribed directly from the DNA
53
Define primary structure
The linear sequence of amino acids that makes up a polypeptide chain
54
Define product
The outputs of a chemical reaction that are formed from the reactants or imputs
55
Define promoter region
A segment of DNA to which RNA polymerase binds to begin transcription
56
Define protein
A polymer made up of amino acid monomers; may consist of a single polymer chain or many polymer bonded together into a functional molecule
57
Define protein secretory pathway
The pathway through which cells package proteins into vesicles for release into the extracellular environment
58
Define proteome
The study of proteomes
59
Define quaternary structure
The structure formed when two or more polypeptides associate into a mature protein
60
Define random coil
A secondary protein structure in which the polypeptide chain does not fold into a specified arrangement
61
Define regulatory gene
A gene whose product switches on or switches off expression of one or more other genes
62
Define repressor protein
A protein that binds DNA to prevent RNA polymerase attaching or transcribing; essentially shuts off gene expression
63
Define ribonucleic acid (RNA)
A type of nucleic acid consisting of a single strand of nucleotides; has essential roles in protein synthesis
64
Define ribosomal RNA (rRNA)
An RNA strand that serves as a structural component of a ribosome
65
Define ribosome
A small structure consisting of RNA and proteins where amino acids are joined to form polypeptides
66
Define RNA polymerase
The enzyme that catalyses the synthesis of RNA
67
Define rough endoplasmic reticulum
Endoplasmic reticulum with ribosomes attached
68
Define secondary structure
The localised folding of a polypeptide chain when neighbouring amino acids bind to each other to form α-helices, β-pleated sheets or random loops
69
Define semi-conservative replication
The replication of DNA in which the product contains one original and one newly made strand
70
Define structural gene
A gene that codes for tRNA, rRNA or a polypeptide other than a regulatory molecule
71
Define substrate
The substances that an enzyme acts on
72
Define subunit
A distinct component of a biological particle; in proteins, it refers to each polypeptide that contributes to the quaternary structure
73
Define template
A pattern that can be used for making many more copies
74
Define template strand
A strand of DNA that is copied during DNA or RNA synthesis
75
Define tertiary structure
The overall three-dimensional shape of a completely folded polypeptide
76
Define transcription
The process by which DNA is copied into mRNA
77
Define transcription factor
A protein that binds to DNA to control the rate of transcription from a gene
78
Define transfer RNA (tRNA)
An RNA molecule that transports an amino acid to the ribosome for assembly into a polypeptide
79
Define translation
The process of turning the nucleotide sequence of mRNA into the amino acid sequence of a polypeptide
80
Define transport vesicle
A small membrane-bound sac containing protein that is transported from the Golgi apparatus to the plasma membrane for release into the extracellular environment
81
Define triplet
A set of three nucleotide codes
82
Define agarose gel
A gel matrix used for electrophoresis
83
Define annealing
A process used in the polymerase chain reaction to join seperate strands of DNA together as a result of hydrogen bonds pairing; occurs when the temperature is lowered
84
Define antibiotic selection
Growing bacteria in the presence of an antibiotic so only cells containing a gene for antibiotic resistance (encoded on a recombinant plasmid) can grow
85
Define bacteriophage
A virus that can infect bacteria and replicate
86
Define bioethics
The study of ethical issues emerging from advancements in biology
87
Define biotechnology
The use of living organisms and biological systems and processes for human benefit
88
Define blunt end
The end of a DNA fragment that is created following cleavage by a restriction enzyme that cuts DNA at the same position on both strands
89
Define Cas9 protein
An endonuclease that cuts double-stranded DNA at a target location in the genome
90
Define CRISPR-Cas9
A bacterial immune defence mechanism in which short RNAs target complementary sequences in viral genomes to guide Cas9 proteins to destroy an invading virus
91
Define crRNA (CRISPR RNA)
RNA transcribed from the CRISPR locus; guides Cas9 proteins to their complementary sequence in the invadung viral DNA genome, targeting it for destruction by Cas9
92
Define DNA ligase
An enzyme that catalyses the formation of a phosphodiester bond between two piece of DNA
93
Define DNA profiling
Comparison of individuals based on patterns of non-coding base sequences in the genome
94
Define frameshift mutation
A mutation in DNA caused by the addition or deletion of a nucleotide or nucleotides resulting in a change in the amino acid sequence and protein being made
95
Define gel electrophoresis
A technique that separates DNA fragments according to their size and charge
96
Define gene cloning
The process of using plasmids and bacteria to make numerous identical copies of a gene
97
Define genetic engineering
Manipulation of genetic material, including altering DNA in an organism to suppress or enhance a gene’s activity, or combining genetic material from different species
98
Define genetic modified organism (GMO)
An organism whose genome has been genetically engineered
99
Define guide RNA
RNA that guides the Cas9 protein to the target sequence in a genome for gene editing
100
Define knock-in organism
An organism in which DNA has been inserted into a specific locus
101
Define knock-out organism
An organism whose DNA has been modified to disable the expression or function of a gene product
102
Define molecular size marker
A set of pieces of DNA of known length that is used to estimate the size of another DNA fragments in a gel
103
Define polymerase chain reaction (PCR)
A cyclical reaction in which DNA polymerase is used to copy a DNA template, making millions of copies of the same piece of DNA
104
Define polymorphism
A variation in DNA sequences among individuals
105
Define primer
A single-stranded DNA molecule that acts as the start of the amplification process
106
Define recombinant DNA technology
The process of transferring a gene from a gene from a cell of one species to the cell of a different species
107
Define recombinant plasmid
A plasmid with foreign DNA inserted into it
108
Define reporter gene
A gene that enables visualisation or quantification of gene expression
109
Define restriction digest reaction
A reaction in which restriction enzymes are incubated with DNA to cut the DNA into fragments at specific restriction sites
110
Define restriction endonuclease (restriction enzyme)
An enzyme that cuts DNA at a specific restriction site
111
Define restriction fragment
A short fragment of DNA generated after the cutting of a longer DNA fragment by a restriction enzyme
112
Define restriction site
A specific nucleotide sequence (usually 4-8 bp) that is recognised as a cleaving site for a restriction enzyme
113
Define short tandem repeat (STR)
A short non-coding region of DNA of up to five bases that is repeated many times in the genome of an organism; the number of times an STR is repeated is variable and can be used in DNA profiling
114
Define sticky end
The end if a DNA fragment that is created following cleavage by a restriction enzyme that cuts DNA at different positions on each strand
115
Define transformation
The process by which the genetic material of an organism id changed by the addition of new genetic material
116
Define transgenic organism
An organism that has been modified by incorporating a piece of foreign DNA into its genome
117
Define vector
A vehicle used to transfer DNA sequences from one organism to another
118
Define wild type
The genotype or phenotype that is most common, or standard, in natural conditions, in contrast to an atypical or mutant form
