Lesson 10: Mutations Flashcards

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1
Q

what are mutations

A

errors in genes and DNA

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2
Q

are mutations only harmful

A

no they can be neutral, harmful, and even beneficial

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3
Q

what are mutations caused by

A

chemicals, environmental factors, radiation, etc.

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4
Q

what triggers mutations to start, what is it caused by and WHAT TYPES OF MUTATIONS ARE THERE

A

it is mainly random
- spontaneous mutations happen in nature by accident
- induced mutations are a result of exposure to a physical or chemical agent
- for instanvce, UV light, etc.

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5
Q

types of mutations- point mutations and chromosome mutations

A

point mutations: failure by the replicating cell to copy the genetic information accurately

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6
Q

what could point mutations be a result of?

A
  • base-pair substitution
  • base-pair insertion
  • base-pair deletion
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7
Q

chromosome mutations

A

involve a mutation involving an entire chromosome or large part of it

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8
Q

example of chromosome mutation and what does it result in

A

non disjunction is an example of a chromosome mutation that can happen in meiosis- it may result in genetic disorders if it happens in gametogenesis or early in development during mitosis

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9
Q

where does most mutations occur?

A

in parts of DNA that do NOT code for genes

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10
Q

do mutations that occur in somatic cells affect future generations

A

no

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11
Q

do mutations that occur in the formation of gametes (sex cells) affect future generations? whats an example

A

yes
- CFTR cystic fibrosis transmembrane regulatory, which is an allele that causes cystic fibrosis

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12
Q

lactose intolerance, what is it

A

a trait in which an individual is not able to digest lactose which is the common sugar in milk

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13
Q

what is lactose intolerance caused by

A

a deficiency of the enzyme lactase which breaks down lactose

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14
Q

what happens if individuals who are lactose intolerant consume lactose

A

the undigested lactose will be metabolized by the intestinal bacteria which can cause bloating, cramping, and diarrhea

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15
Q

how come 75% of human adults are lactose intolerant?

A
  • adults never consumed milk in human history
  • when babies are born, they are lactose tolerant as they need to digest their mother’s milk
  • when they grow, they may lose their ability to produce the enzyme to digest dairy products
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16
Q

how are non lactose intolerant adults able to digest lactose

A

due to genetic mutations that inherited this gene

17
Q

sickle cell anemia, what is it (base pair… )

A

a mutation which is caused by a single nitrogenous base substitution- single adenine base is substituted by a thymine

17
Q

what happens to blood cells when someone has sickle cell anemia

A

it causes red blood cells to not be healthy and lose its round shape- instead, they turn c-shaped and less effective at moving oxygen around the body through blood

18
Q

what parasite/disease allows for having sickle cell to be beneficial? hows that?

A

Malaria
- when the parasite enters a red blood cell of an individual with SCA, it causes the oxygen levels in the cell to drop and it becomes sickle shaped
- because the infected red blood cell is no longer doing its job, its removed and destroyed by the body along with the parasite (which obviously kills it)
-

19
Q

process of base excision repair

A

where one enzyme snips out the damaged base and the other enzymes come in to trim around the site and replace the nucleotides

20
Q

how does UV light damage DNA

A

UV light can cause two nucleotides to stick together, which distorts the DNA’s double helix shape

21
Q

what kind of repair does UV light damage require? what is the process

A

nucleotide excision repair, when a team of proteins removes a long strand of 24 or so nucleotides, and replaces them with fresh ones

22
Q

high radiation such as gamma rays and x rays severs what of the DNA?

A

one or both strands of the DNA backbone

23
Q

what repair do we use for double stranded breaks in DNA

A

homologous recombination or non-homologous end joining

24
Q

describe and explain homologous recombination

A

it uses an undamaged section of similar DNA as a template- enzymes interlace the damaged and undamaged strands, get them to exchange sequences of nucleotides, and fill in the missing gaps to end up with two complete double stranded segments

25
Q

describe and explain non-homologous end joining

A

a series of proteins trims off a few nucleotides and then fuses the broken ends back together

26
Q

how is non-homologous end joining inaccurate sometimes?

A

it can cause genes to get mixed up or moved around a lot

27
Q
A