sb3 Flashcards

1
Q

What are the advantages and disadvantages of asexual reproduction?

A

Advantages -
—> don’t need to find a mate
—> rapid reproductive cycle

Disadvantages -
—> no variation

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2
Q

What are the advantages and disadvantages of sexual reproduction?

A

Advantage -
—> variation in population

Disadvantage -
—> need to find a mate

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3
Q

What is the result of meiosis?

A
  • 4 daughter cells ( divides twice )
  • all haploid
  • all genetically different
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4
Q

What is DNA?

A
  • two strands forming a double helix
  • strands linked by complimentary base pairs linked with weak hydrogen bonds
  • nucleotides that have a sugar and phosphate group with one of the four bases
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5
Q

What is the genome?

A

Entire DNA of an organism

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6
Q

What is a gene?

A

A section of DNA that codes for a specific protein

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7
Q

What do we see after DNA is extracted from fruits?

A

A white precipitate at the top of the tube ——> this is the DNA

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8
Q

Why do we add pineapple juice when extracting DNA?

A

Contains enzyme called bromelain which breaks down proteins attached to the DNA
—> helps us see DNA more clearly

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9
Q

Why do we add ethanol when extracting DNA?

A

Causes DNA to precipitate out of the solution

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10
Q

What is a gamete?

A

An organisms reproductive cell
E.g sperm and egg

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11
Q

What is an allele?

A

A different version of the same gene

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12
Q

What is a dominant allele?

A

Only one of the alleles is needed for it to be expressed (always expressed)

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13
Q

What is a recessive allele?

A

Both alleles need to be recessive in order for it to be expressed

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14
Q

What is a genotype?

A

The alleles an organism has e.g Aa

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15
Q

Whats a phenotype?

A

The physical characteristics of an organism

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16
Q

What is a zygote?

A

A diploid cell formed after fertilisation

17
Q

What are the causes of variation that influence phenotype?

A
  1. Genetic variation -
    —> different characteristics as a result of mutation and sexual reproduction
  2. Environmental variation -
    —> different characteristics caused by someone’s environment
18
Q

How does genetic variation arise in a population

A

Through mutations

19
Q

What do genetic mutations do?

A
  • they have no affect on phenotype
  • they have sometimes a small affect
  • they have a significant affect on a phenotype rarely
20
Q

What is seen when DNA is precipitated out of the solution?

A

White strands

21
Q

What are some benefits of mapping someones genome?

A
  • assesses risk of developing cancer
  • shows if they are a carrier of a disease
22
Q

What happens in transcription and translation?

A

Transcription —

  1. RNA polymerase binds to non-coding section of DNA
  2. RNA polymerase produces a complimentary mRNA strand
  3. Complimentary base pairs: c-g and a-u
  4. mRNA leaves nucleus

Translation —

  1. mRNA leaves nucleus
  2. Attatches to a ribosome
  3. Triplets of bases in mRNA code for specific amino acids
  4. Transfer of amino acids to ribosome by tRNA
  5. Amino acids are linked to form polypeptides
23
Q

why don’t all mutations have negative effects?

A
  • some are neutral
  • some could increase chances of survival
24
Q

how can a mutation cause an enzyme to not function properly?

A
  • mutations are changes in base sequence
  • changes sequence of mRNA
  • change in order of amino acids
  • changes shape of enzymes active site
  • prevents substrate from binding to it
  • enzyme would function less
25
Q

would mutation that cause change to enzyme have occurred in coding or non coding dna?

A
  • coding part
  • it codes for sequence of amino acids
  • mutations in non-coding would only affect quantity of protein
26
Q

what is a drug that kills viruses?

A

antiretroviral

27
Q

where does lipase usually carry out fat digestion?

A

small intestine

28
Q

how can a mutation in an allele affect functioning of protein?

A
  • different sequence of amino acids
  • different sequence of polypeptide formed
  • protein will fold differently
29
Q

how can a mutation in non coding DNA prevent transcription?

A
  • reduces binding of RNA polymerase
  • mRNA is not produced