Genes, Chromosomes, Genomes Flashcards

1
Q

What is the central dogma of molecular biology?

A

there is a directional flow from DNA to protein via the messenger RNA (mRNA)

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2
Q

What is DNA transcribed to?

A

mRNA

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3
Q

What is mRNA translated to?

A

protein

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4
Q

What is gene expression?

A

process of going from DNA to protein

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5
Q

What is a codon?

A

triplets of bases that code for an amino acid

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6
Q

What are the three components to the chemical makeup of DNA?

A

Pentose sugar
Nucleotides
Phosphate groups

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7
Q

What are the pyrimidines?

A

Cytosine
Thymine
Uracil

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8
Q

What are the purines?

A

Adenine

Guanine

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9
Q

What is the difference betweeen pyrimidines and purines?

A

purines contain a sixmembered nitrogencontaining ring fused to an imidazole ring
whereas pyrimidines contain only a sixmembered nitrogencontaining ring

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10
Q

What makes a nucleoside?

A

base + sugar

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11
Q

What is a nucleotide?

A

monomer unit of DNA/RNA

base + sugar + phosphate group

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12
Q

What does a phosphodiester bond link?

A

Phosphate and sugar group for the sugar-phosphate backbone of DNA

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13
Q

What are combinations of base pairs?

A

G-C

A-T/U

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14
Q

How many hydrogen bonds between G-C bases?

A

3

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15
Q

How many hydrogen bonds can adenine form to another base?

A

2

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16
Q

Which bonds are stronge A-T or G-C?

A

G-C

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17
Q

What is hybridisation?

A

process of combining two complementary single-stranded DNA or RNA molecules

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18
Q

What is renaturation also reffered to as?

A

hybridisation

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19
Q

True or False?

Tm is the temp at which all the DNA has melted?

A

False

Tm is when half the DNA has melted

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20
Q

True or False?

Tm is lower in DNA with high G-C content

A

False

Tm is higher in DNA with high G-C content

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21
Q

True or False?

GC rich regions of DNA are more strongly bonded

A

True

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22
Q

True or False?

Repeats in DNA sequences lead to longer renaturation times

A

False

repeats hybridise faster because there are more copies

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23
Q

How much of the human genome is actually genes?

A

~25%

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24
Q

What percent of the human genome encodes for proteins?

A

~1.5%

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25
What is an allele?
different forms of genes
26
What study found that genes lie on chromosomes?
1910 | Thomas Hunt Morgan
27
Who found that Chromosomes contain genes in linear array?
19-13 | Alfred Henry Sturtevant
28
What is most of the gene made of?
Introns and regulatory DNA sequences
29
What is a gene?
stretch of DNA that functions as a unit to give rise to either RNA or a protein
30
What is the sense strand also reffered to as?
The coding strand
31
What is the antisense strand also reffered to as?
The template strand
32
What happens to the sense strand?
Transcribed to RNA and then translated into a protein
33
Which strand is the coding strand?
The sense strand which can be either strand of the DNA strand
34
What does DNA having antiparallel strands result in?
the strand can be read either way to give different proteins
35
True or False? | A gene encodes one (or many) polypeptides or structural RNAs
True
36
True or False? | Genes on the same chromosome segregate independently
False | Genes on different chromosomes segregate independently genes on the same chromosome are said to be linked
37
True or False? | Most of the human genome is made up of gene sequences
False | Only ~25% of human genome is made of genes
38
True or False? | Most of the gene sequence is used to encode the protein
False | Mostly control sites and introns (in eukaryotes)
39
What are control sites?
provide binding sites for proteins | regulate gene expression
40
What are coding regions?
expressed via RNA synthesis
41
What are promoters and terminates?
Control regions
42
What does a promoter do?
Contain binding sites for transcription machinery (RNA polymerases) Contain binding sites for regulatory factors that control when and where a gene is expressed
43
What does a terminator do?
Sites which signal when synthesis of mRNA should cease
44
Compared to prokaryotic genes in the control regions what extra parts do they have?
Enhancer regions
45
Compared to prokaryotic genes in the coding region what extra parts do they have?
introns and exons
46
What are exons?
Sequences that encode protein in the final/mature mRNA
47
What are introns
Sequences which break up the coding sequence Need to be removed during maturation of mRNA Few and small in simple organisms More common and can be large in higher eukaryotes
48
What does splicing do?
removes introns and links the coding sequences found in exons
49
What flank the coding region to allow accurate splicing?
short donor and acceptor sites
50
What mediates splicing?
The spliceosome
51
What is snRNA?
small nuclear RNA
52
What is alternative splicing?
Different exons from a gene used to code for various proteins
53
True or False? | Control regions are expressed mRNA synthesis
False | Coding regions are expressed mRNA synthesis
54
True or False | Introns are sequences that encode the mature mRNA
False Introns are spacer regions between exons exons encode for mature mRNA
55
True or False? | Promoters are used to control gene expression and are found downstream of the coding region
False | Promoter regions are usually found upstream of coding region
56
True or False? Alternative splicing is where different exons from the same coding region can be ligated to form alternative mRNAs leading to many different protein sequences
True
57
What is the genome?
The entire “library” of genetic instructions that an organism inherits
58
What is the functional unit of the genome?
the gene
59
How many base pairs in the human genome?
over 3 billion
60
How many base pairs in the E.coli genome?
4.6million
61
Do closely related species need to have similar number of chromosomes?
Nope
62
What is probably the minimum number of required genes for a viable cell?
200-300 genes
63
What is mycoplasma labatorium?
a simple synthetic organisms | created by Craig Venter
64
What is a metagenome?
The sequencing of the collective genomes of all microorganisms that exist within a particular environment