Genes and Genome Flashcards

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1
Q

Genome

A

all hereditary material in a virus, cell, or organism, including but not confined to genes

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2
Q

Does genome only refer to DNA?

A

no

a viruses genome can be made out of RNA

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3
Q

Does genome only include the coding regions?

A

no

includes coding and non-coding regions

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4
Q

Size of eukaryotic and prokaryotic genomes

A

eukaryotes have more DNA than prokaryotes

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5
Q

Structural differences between eukaryotic and prokaryotic genomes

A

eukaryotes have multiple linear chromosomes

prokaryotes have a single circular chromosome

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6
Q

plasmids

A

circular components of prokaryotes genome that can be transferred between cells

contain a subset of genetic information that may be needed to pass on to another cell

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7
Q

packaging of eukaryotic vs prokaryotic DNA and effects

A

eukaryotes DNA is more tightly packed around histones

leads to eukaryotes having more chemical modifications of genome because methyl groups are added to histones to control packaging

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8
Q

genetic makeup of eukaryotic vs prokaryotic genomes

A

eukaryotes have many more regions of non-coding DNA

most of prokaryotic DNA codes for proteins

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9
Q

why do prokaryotes express mutant phenotypes more often?

A

they are haploid

if one copy of the gene is mutated, the phenotype is mutated

no extra copy to use in the event of a mutation

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10
Q

do prokaryotes have introns and exons?

A

no

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11
Q

operons

A

a feature of the prokaryotic genome

multiple genes that are transcribed together onto single mRNA but translated independently

can turn and turn off all the genes in an operon at the sametime

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12
Q

advantage and disadvantage of operons

A

advantage: efficient
disadvantage: cannot fine tune specific genes

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13
Q

similarity between prokaryotic and eukaryotic genome

A

both contain double stranded DNA

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14
Q

exons

A

genes that are expressed

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15
Q

introns

A

interventions that contain regulatory sequences

allow eukaryotes to turn on specific genes at specific times

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16
Q

what do introns promote?

A

cell specialization because certain genes can be turned on at certain moments in certain cell-types

17
Q

What does looking at the bacteria genome show us?

A
  1. there are very little non-coding regions. mostly genes.
  2. regulatory sequences are physically close to the promoter they affect
  3. genes within an operon are related to eachother
18
Q

regulatory sequences

A

sites where regulatory proteins like activators and inhibitors bind

19
Q

what does an arrow indicate in a genome?

A

promoter

20
Q

What does looking at the eukaryotic genome show us?

A
  1. one gene can encode for multiple products by splicing together different combinations of exons
  2. regulatory elements are found throughout the genome
  3. repetitive sequences
  4. there is lots of space for noncoding regions
21
Q

alternative splicing

A

putting together different combinations of exons to allows one gene to encode for multiple products

22
Q

do genes go in both directions?

A

yes

they can be on the top or bottom DNA strand of the double helix

this is true for both prokaryotes and eukaryotes

23
Q

what is half of repeated DNA in eukaryotes?

A

transposable elements / transposons

24
Q

transposons

A

can be copied and inserted elsewhere in the genome, which is why they account for a large percentage of the repeated DNA

25
Q

what can cause repeated DNA?

A

slippage during DNA replication by DNA polymerase

26
Q

who discovered transposons?

A

Barbara McClintock

she used corn to discover that DNA can jump which produces different looking phenotypes

27
Q

what are transposons composed of?

A
  1. long interspersed nuclear element (LINE)

2. gene for integrase which allows it move

28
Q

Lateral gene transfer

A

often observed in prokaryotes

genes can be transferred from one species to another

responsible for chloroplasts, mitochondria, and the spread of antibiotic resistance

29
Q

gene duplication

A

mistakes during crossing over can result in genes being replicated

30
Q

what does gene duplication often result in?

A

gene “families”

genes with similar functions

31
Q

example of a gene family?

A

hemoglobin groups

have different genes for oxygen carrying during different points in development

B-globin

32
Q

How do transposons work?

A
  1. RNA polymerase makes mRNA of whole transposon
  2. LINE mRNA leaves the nucleus to be translated
  3. mRNA returns to nucleus
  4. Reverse transcriptase converts mRNA to LINE cDNA
  5. Integrase cuts the chromosomal DNA and inserts the LINE cDNA
33
Q

What does integrase do?

A

cuts the chromosomal DNA in order for the LINE cDNA to be inserted

34
Q

Where does LINE DNA originate?

A

it is part of chromosomal DNA sequence