2B Proteins and DNA Flashcards

1
Q

catalyst

A

a substance that speeds up a reaction without changing the substances produced or being changed itself

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2
Q

enzymes

A

proteins that act as biological catalysts for a specific reaction or group of reactions

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3
Q

specificity

A

the characteristics of enzymes that means that each enzyme will catalyse only a specific reaction or group of reactions; this is due to the very specific shapes which come form the tertiary and quaternary structures

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4
Q

anabolic reaction

A

a reaction that builds up (synthesises) new molecules in a cell

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5
Q

catabolic reaction

A

a reaction which breaks down substances within a cell

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6
Q

metabolism

A

the sum of the anabolic and catabolic processes in a cell

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7
Q

metabolic chain

A

a series of linked reactions in the metabolism of a cell

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8
Q

extracellular enzymes

A

enzymes that catalyse reactions outside of the cell in which they were made

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8
Q

intracellular enzymes

A

enzymes that catalyse reactions within the cell

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9
Q

mononucleotides

A

molecules with three parts - a 5-carbon pentose sugar, a nitrogen-containing base and a phosphate group - joined by condensation reactions

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10
Q

adenosine triphosphate ATP

A

a molecules that acts as the universal energy supply molecule in cells; it is made up of the base adenine, the pentose sugar ribose and three phosphate groups

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11
Q

deoxyribonucleic acid (DNA)

A

a nucleic acid that is the genetic material in many organisms

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12
Q

ribonucleic acid (RNA)

A

a nucleic acid which is the genetic material in some organisms and is involved in protein synthesis

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13
Q

ribose

A

a pentose sugar that is part of the structure of RNA

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14
Q

deoxyribose

A

a pentose sugar that is part of the structure of DNA

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15
Q

purine base

A

a base found in nucleotides that has two nitrogen-containing rings
(adenine, guanine)

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16
Q

adenine

A

a purine base found in DNA and RNA

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17
Q

pyrimidine base

A

a base found in nucleotides that has one nitrogen-containing ring
(cytocine, thymine, uracil)

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18
Q

thymine

A

a pyrimidine base found in DNA

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19
Q

guanine

A

a purine base found in DNA and RNA

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19
Q

cytosine

A

a pyrimidine base found in DNA and RNA

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20
Q

uracil

A

a pyrimidine base found in RNA

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21
Q

nucleic acids/polynucleotides

A

polymers made up of many nucleotide monomer units that carry all the information needed to form new cells

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22
Q

phosphodiester bond

A

bond formed between the phosphate group of one nucleotide and the sugar of the next nucleotide in a condensation reaction

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23
conservative replication
a model of DNA replication which suggests that the original double helix remains intact and some way instructs the formation of a new, identical double helix made up entirely of new material
23
complementary base pairs
complementary purine and pyrimidine bases which align in a DNA helix, with hydrogen bonds holding them together (C-G, A-T)
24
genome
the entire genetic material of an organism
25
semiconservative replication
the accepted model of DNA replication in which the DNA unzips and new nucleotides align along each strand; each new double helix contains one strand of the original DNA and one strand made up of new material
26
isotopes
different atoms of the same element, with the same number of protons but a different number of neutrons; isotopes have the same chemical properties
27
DNA helicase
an enzyme involved in DNA replication that unzips the two strands of the DNA molecules
28
translation
the process by which proteins are produces, via RNA, using the genetic code found in the DNA; it takes place on the ribosomes
29
DNA polymerase
an enzyme involved in DNA replication that lines up the new nucleotides along the DNA template strands
30
DNA ligase
an enzyme involved in DNA replication that catalyses the formation of phosphodiester bonds between the nucleotides
31
ribosomes
the site of protein synthesis in the cell
32
triplet code
the code of three bases that is the basis of the genetic information in the DNA
33
gene
a sequence of bases on a DNA molecules which codes for a sequence of amino acids in a polypeptide chain (that affects a characteristic in the phenotype of the organism)
34
codon
a sequence of three bases in DNA or mRNA
35
messenger RNA
the RNA formed in the nucleus that carries the genetic code out into the cytoplasm
36
complementary strand
the strand of RNA formed that complements the DNA acting as the coding strand
37
degenerate code
- a code containing more information than is needed - 20 amino acids, 64 base triples - some amino acid are coded for by more than one base triplet
38
sense strand
the DNA strand that carries the code for the proteins to be produced
38
non-overlapping
a code where each codon codes for only one thing with no overlap between codons
39
point mutation
a change in a single base of the DNA code
40
antisense strand (template strand)
the DNA strand which acts as a template for an mRNA molecule
41
RNA polymerase
the enzyme that polymerises nucleotide units to form RNA in a sequence determined by the antisense strand of DNA
41
start codon
the sequence of bases which indicates the start of an amino acid chain - TAC; this is the code for the amino acid methionine
42
stop codon
one of three sequences of bases which indicate the end of an amino acid chain
43
anticodon
a sequence of three bases on tRNA that are complementary to the bases in the mRNA codon
44
transfer RNA
small units of RNA that pick up specific amino acids from the cytoplasm and transport them to the surface of the ribosome to align with the mRNA
45
translation
the process by which the DNA code is converted into a protein from the mRNA codon
46
transcription
the process by which the DNA sequence is used to make a strand of mRNA in the nucleus
46
polysomes
groups of ribosomes, joined by a thread of mRNA, that can produce large quantities of a particular protein
47
start codon
TAC (in DNA)
48
what amino acid does the start codon code for?
methionine
49
the first amino acid in every polypeptide chain is?
methionine
50
examples of intracellular enzymes
DNA polymerase, DNA ligase
51
examples of extracellular enzymes
digestive enzymes, lysozyme
52
what type of enzymes are trypsin and pepsin?
protease enzymes (protein digesting enzymes)
53
how does temperature have an effect on the rate of a reaction?
the number of successful collisions leading to a reaction increases at higher temperatures
54
temperature coefficient Q10
55
enzyme action (in a catabolic reaction)
62
how does a phosphodiester bond form?
by a condensation reaction between the phosphate group of one nucleotide and the hydroxyl group on carbon 3 of the pentose sugar of another nucleotide
63
describe the process of DNA synthesis
- the enzyme DNA helicase breaks the hydrogen bonds between the complementary base pairs of the original DNA molecule - teh DNA double helix unwinds/unzips, and the two strands separate - free nucleotides in the nucleus align iwht the complementary bases of the exposed polynucleotide strands, due to complementary base pairing - 2 hydrogen bonds A,T 3 between C,G - DNA polymerase catalyses the formation of phosphodiester bonds - DNA helicase moves up the molecule from the 3' end to the 5' end of the leading strand - DNA polymerase can only form phosphodiester bonds on the leading strand continuously - fragments on lagging strand (okazaki fragments) - DNA ligase joins the okazaki fragments together
64
how many hydrogen bonds form between A & T?
2
65
how many hydrogen bonds form between G & C?
3
66
in what direction does DNA helicase move up the DNA molecule?
from the 3' end to the 5' end of the leading strand
67
how does DNA polymerase bind to the parent strand?
DNA polymerase can only bind to the 3' end of the parent strand
68
what does ATP stand for?
adenosine triphosphate
69
what does a ATP molecule consist of?
- a nitrogenous base Adenine - a ribose sugar - three phosphate groups
70
what are ribosomes made up of?
rRNA and proteins
71
ribosomes are the site of what?
site of proteins synthesis
72
what do ribosomes hold together during translation, and what do they act as?
they hold together the mRNA and tRNA and act as enzymes controlling the process of protein synthesis
73
describe the process of transcription
1. DNA helicase unwinds and unzips the DNA, breaking hydrogen bonds between complementary bases 2. beginning at the start codon, pre-mRNA forms alongside the template strand 3. RNA polymerase catalyses formation of phosphodiester bonds between the nucleotides in the pre-mRNA, until the chain reaches a stop codon 4.mRNA chain separates from the DNA template 5. the DNA chains of the double helix rejoin 6. splicing converts pre-mRNA into mRNA, and introns are removed 7. mRNA leaves nucleus, through nuclear pore, to ribosomes for translation
74
introns
non-coding sections
75
exons
coding sections
76
describe the process of translation
1. mRNA molecules attaches to surface of the ribosome at at the start codon 2. tRNA carry individual amino acids to the surface of ribosome 3. tRNA molecules with the complementary anticodon to the start codon in the mRNA, aligns opposite the mRNA held in place by the ribosome 4. enzymes join the amino acids together via a peptide bond 5. tRNA then brakes away and return to cytoplasm to pick up another amino acid 6. ribosome moves along mRNA molecule until it reaches the stop codon
77
how many tRNA molecules can a ribosome hold at a time?
2
78
where is tRNA found?
in the cytoplasm
79
where is mRNA formed?
in the nucleus
80
mRNA
carries the instructions for a polypeptide from the DNA in the nucleus to the ribosomes where proteins are made
81
tRNA
picks up specific amino acids from the protoplasm and carries them to the surface of ribosomes
82
rRNA
makes up the bulk of the ribosomes themselves