Ch 2 Nucleic Acids & Proteins Flashcards
(101 cards)
1
Q
protein
A
A biomacromolecule made of amino acid chains folded into a 3D shape.
2
Q
polypeptide
A
A long chain of amino acids. Proteins can be made of one or many polypeptides.
3
Q
proteome
A
All the proteins that are expressed by a cell or organism at a given time.
4
Q
enzyme
A
An organic molecule, typically a protein, that catalyses (speeds up) specific reactions.
5
Q
peptide hormone
A
A protein signalling molecule that regulates physiology or behaviour.
6
Q
antibody
A
A protein produced by plasma cells during the adaptive immune response that is specific to an antigen and combats pathogens in a variety of ways. Also known as immunoglobulin.
7
Q
carboxyl group
A
The functional group on amino acid molecules that contains a hydroxyl group (OH) and an oxygen double- bonded to a carbon atom.
8
Q
amino group
A
The functional group on amino acid molecules that is made up of one nitrogen and two hydrogens (NH2).
9
Q
R-group
A
The variable portion of an amino acid molecule. It can be one of twenty variations and determines the identity of the amino acid.
10
Q
hydrophobic
A
Having a tendency to repel and be insoluble in water.
11
Q
hydrophilic
A
Having a tendency to be attracted to and dissolve in water.
12
Q
monomer
A
A molecule that is the smallest building block of a polymer.
13
Q
polymer
A
A large molecule that is made up of small, repeated monomer subunits.
14
Q
condensation reaction
A
A reaction where two monomers join to form a larger molecule, producing water as a by-product.
15
Q
peptide bond
A
The chemical bond linking two amino acids.
16
Q
primary structure
A
The first level of protein structure, which refers to the sequence of amino acids in a polypeptide chain.
17
Q
tertiary structure
A
The functional 3D shape of a polypeptide chain.
18
Q
secondary structure
A
The level of protein structure where the amino acid chain forms either alpha-helices, beta-pleated sheets, or random coils.
19
Q
quaternary structure
A
The level of protein structure where multiple polypeptide chains bond together, or other non-protein groups are added to form a fully functional protein.
20
Q
alpha helix
A
An organised coiled secondary structure of proteins.
21
Q
beta-pleated sheet
A
An organised folded secondary structure of proteins.
22
Q
random coil
A
An irregular secondary structure of proteins that is neither an alpha helix nor a beta-pleated sheet.
23
Q
disulphide bond
A
A strong covalent bond occurring between two sulphur atoms.
24
Q
prosthetic group
A
A non-protein group bound to a protein. For example, a vitamin or ion.
25
nucleic acid
The class of macromolecule that includes DNA and RNA. All nucleic acids are polymers made out of nucleotide monomers.
26
polymer
A large molecule that is made up of small, repeated monomer subunits.
27
nucleotide
The monomer subunit of nucleic acids. Made up of a nitrogen-containing base, a five- carbon sugar molecule (ribose in RNA and deoxyribose in DNA), and a phosphate group,
28
DNA (deoxyribonucleic acid)
A double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival.
29
RNA (ribonucleic acid)
A single- stranded nucleic acid chain made up of nucleotides. Includes mRNA, rRNA, and tRNA.
30
phosphodiester bond
A strong covalent bond linking a five-carbon sugar to a phosphate group.
31
condensation reaction
A reaction where two monomers join to form a larger molecule, producing water as a by-product.
32
sugar-phosphate backbone
A strong covalently linked chain of five-carbon sugar molecules and phosphate groups in a nucleic acid chain.
33
chromosome
A structure made of protein and nucleic acids that carries genetic information.
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gene
A section of DNA that carries the code to make a protein.
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genome
The complete set of DNA housed within an organism.
36
antiparallel
A characteristic of DNA strands describing how each strand runs in an opposite direction to the other. One strand runs in a 3’-->5’ direction and the other runs in a 5’-->3’ direction.
37
complementary base pairing
Describes which nucleotides can form hydrogen bonds with each other. C pairs with G, A pairs with T (or U in RNA).
38
double helix
The structure of double-stranded DNA in the nucleus of eukaryotic cells, where each DNA strand wraps around a central axis.
39
nuclear DNA
DNA that is located in the nucleus of a cell.
40
messenger RNA (mRNA)
RNA molecules that are produced during transcription and carry genetic information from the nucleus to the ribosomes.
41
transfer RNA (tRNA)
RNA that recognises specific codons on the mRNA strand and adds the corresponding amino acid to the polypeptide chain during protein synthesis.
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ribosomal RNA (rRNA)
RNA that is a key structural component of ribosomes, which assemble proteins.
43
transcription
The process whereby a sequence of DNA is used as a template to produce a complementary sequence of mRNA.
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genetic code
The set of rules by which information is encoded in genetic material.
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translation
The process where an mRNA sequence is read to produce a corresponding amino acid sequence to build a polypeptide.
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triplet
The sequence of three nucleotides in DNA coding for one amino acid.
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codon
The sequence of three nucleotides in mRNA coding for one amino acid.
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start codon
The sequence of three nucleotides in mRNA that signals the start of translation.
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stop codon
The sequence of three nucleotides in mRNA that signals the end of translation.
48
promoter
The sequence of DNA to which RNA polymerase binds.
49
RNA polymerase
The enzyme responsible for constructing a pre-mRNA sequence from a DNA sequence during transcription.
50
TATA box
A type of promoter region.
50
enzyme
An organic molecule, typically a protein, that catalyses (speeds up) specific reactions.
51
introns
Non-coding regions of DNA that do not code for proteins. They are spliced out during RNA processing.
52
exons
Regions of DNA that code for proteins and are not spliced out during RNA processing.
53
termination sequence
A sequence of DNA that signals the end of transcription.
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operator
A short region of DNA that interacts with repressor proteins to alter the transcription of an operon.
55
gene expression
The process of reading the information stored within a gene to create a functional product, typically a protein.
55
repressor protein
A protein coded for by a regulatory gene that prevents gene expression by binding to its operator.
56
leader region
The segment of DNA or mRNA that immediately precedes the coding region. Also known as the leader segment or leader sequence.
57
gene expression
The process of reading the information stored within a gene to create a functional product, typically a protein.
58
precursor messenger RNA (pre-mRNA)
The immediate product of transcription of a DNA sequence. Requires modifications before it can undergo translation.
58
transcription
The process whereby a sequence of DNA is used as a template to produce a complementary sequence
of mRNA.
59
transcription factor
Proteins that bind to the promoter region and control the functioning of RNA polymerase.
60
RNA polymerase
The enzyme responsible for constructing a pre-mRNA sequence from a DNA sequence during transcription.
61
template strand
The strand of DNA transcribed by RNA polymerase to produce a complementary pre-mRNA strand.
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coding strand
The strand of DNA not transcribed by RNA polymerase, contains an identical sequence to the mRNA strand produced (except thymine is replaced with uracil in mRNA).
63
termination sequence
A sequence of DNA that signals the end
of transcription.
64
ribosome
An organelle made of rRNA and protein that is the site of protein synthesis. Can be free in the cytosol or attached to the rough endoplasmic reticulum.
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5’ methyl-G cap
A molecule added to the 5’ end of pre-mRNA during RNA processing.
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3’ poly-A tail
A chain of adenine nucleotides added to the 3’ end of pre-mRNA during RNA processing.
67
splicing
Process where introns are cut out of a pre-mRNA molecule, and exons are joined together.
68
spliceosome
The enzyme that removes introns from the pre- mRNA molecule and joins exons together during RNA processing.
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alternative splicing
The process where different exons may be spliced, resulting in a single gene producing multiple different mRNA strands.
70
anticodon
The sequence of three nucleotides on a tRNA molecule that recognises a specific sequence of three nucleotides (codon) on an mRNA strand.
71
gene regulation
The control of gene expression, typically achieved by switching transcription on or off.
72
exocytosis
A type of bulk transport that moves large substances out of a cell.
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gene expression
The process of reading the information stored within a gene to create a functional product, typically a protein.
74
structural gene
A segment of DNA that doesn’t code for regulatory proteins, but instead codes for proteins that play a role in the structure or function of a cell or organism.
75
repressor protein
A protein coded for by a regulatory gene that prevents gene expression by binding to its operator.
75
regulatory gene
A segment of DNA responsible for producing proteins that control the expression of other genes.
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activator protein
A protein coded for by a regulatory gene that increases gene expression.
77
promoter
The sequence of DNA to which RNA polymerase binds.
78
operator
A short region of DNA that interacts with repressor proteins to alter the transcription of an operon.
79
operon
A cluster of linked genes that all share a common promoter and operator and are transcribed at the same time.
80
trp operon
A series of genes within certain species of bacteria that encode for the production of the amino acid tryptophan.
81
trp operon repression
Mechanism for gene regulation within the trp operon whereby repressor proteins stop the initiation of transcription when tryptophan levels are high.
82
attenuator sequence
Part of the leader region within the trp operon that allows for attenuation.
82
conformational change
A change in the three-dimensional shape of macromolecules such as proteins.
83
trp operon attenuation
Mechanism for gene regulation within the trp operon whereby the premature ceasing of translation stops transcription when tryptophan levels are high.
83
leader region
The segment of DNA or mRNA that immediately precedes the coding region. Also known as the leader segment or leader sequence.
84
terminator hairpin
A loop formed in mRNA in the presence of tryptophan that ceases transcription of the trp operon.
85
antiterminator hairpin
A loop formed in mRNA when tryptophan is not present that ensures the transcription of the structural genes in the trp operon.
86
vesicle
A small fluid-filled organelle enclosed in a phospholipid membrane that transports substances around the cell.
87
secretory products
The substances inside a vesicle that are being transported out of the cell.
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active transport
The movement of molecules across a semipermeable membrane requiring an energy input.
87
bulk transport
A type of active transport that uses vesicles to move large molecules or groups of molecules into or out of the cell.
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plasma membrane
The phospholipid bilayer with embedded proteins which separates the intracellular environment from the extracellular environment.
89
rough endoplasmic reticulum (RER)
A membranous organelle shaped like a series of connected, flattened cylinders that folds and transports proteins via its attached ribosomes.
90
Golgi apparatus
An organelle made of flattened sacs of membrane involved in modifying, sorting, and packaging proteins. Also known as the Golgi body or Golgi complex.
91
mitochondrion (pl. mitochondria)
A double-membrane-bound organelle that is the site of the second and third stages of aerobic cellular respiration.
