Topic 4 Booklet Flashcards

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1
Q

What does degenerate mean?

A

More than one triplet for each amino acid

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2
Q

Define non-overlapping

A

Each base is part of only one triplet

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3
Q

What are some aseptic techniques?

A
  1. Keep lid on Petri dish/ open lid as little as possible
    - to prevent unwanted bacteria contaminating the dish
  2. Wear gloves/mask / wash hands
    - to prevent contamination from bacteria on hands/mouth
  3. Use sterile pipette/ flame the loop
    - to maintain a pure culture of bacteria
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4
Q

Give the two types of molecule form which a ribosome is made

A

Ribosomal RNA and amino acids

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5
Q

Describe the role of a ribosome in the production of a polypeptide.

A
  1. mRNA binds to the ribosome
  2. Two codons/ binding sites
  3. Allows tRNA with anticodons to bind
  4. Catalyses formation of peptide bond between amino acids
  5. Moves along (mRNA to the next codon)
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6
Q

Define species

A

A group of organisms that are able to produce fertile offspring

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7
Q

Define species richness

A

The number of different species in a community

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8
Q

Explain how the chromosome number is halved during meiosis

A
  1. Homologous chromosomes
  2. One of each pair goes to each daughter cell
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9
Q

Describe the process of crossing over and explain how it increases genetic diversity

A
  1. Homologous pairs of chromosomes form a bivalent
  2. Chiasmata form
  3. Alleles are exchanged
  4. Producing new combinations of alleles
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10
Q

Explain how differences in the primary structure of haemoglobin molecules can provide evidence of phylogenetic relationships between species

A
  1. Mutations change base/ nucleotide sequence
  2. Causing change in amino acid sequence
  3. Mutations build up over time
  4. More mutations between distantly related species
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11
Q

Describe and explain the appearance of one chromosome during meiosis (before division)

A
  1. Chromosome is formed of two chromatids
  2. Because DNA replication
  3. Sister chromatids held together by centromere
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12
Q

Describe what happens in meiosis I

A
  1. Chromosome in homologous pair
  2. One of each into daughter cells
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13
Q

Identify one event that occurs in meiosis II but not meiosis I

A

Separation of chromatids

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14
Q

Name two ways in which meiosis produces genetic variation

A
  1. Crossing over
    Independent segregation
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15
Q

Explain the importance of meiosis in the life cycles of organisms which reproduce sexually

A
  1. Meiosis produces haploid cells
  2. When gametes fuse, the diploid number is restored
  3. This keeps the chromosome number constant
  4. Introduces GENETIC variation
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16
Q

Suggest one source of DNA from deceased organisms

A

Preserved remains, skin, bones

17
Q

Suggest reasons why populations might show very low levels of genetic diversity

A
  1. Inbreeding
  2. Population might have been very small
18
Q

What is genetic diversity

A

The number of different alleles of a gene in a population

19
Q

Describe the process of natural selection

A
  1. New alleles for a gene are created by random mutations
  2. If the new alleles increases the chances of the individual to survive in that environment, they are more likely to survive and reproduce
  3. Reproduction passes on the advantageous allele to the next generation
  4. Over many generations the allele increases in frequency in the population
20
Q

What is directional selection

A
  1. One of the extremes has the selective advantage
  2. Occurs when there is a change in the environment
  3. The model trait changes
21
Q

What is stabilising selection

A
  1. The modal trait has the selective advantage
  2. Occurs when there is no change in the environment
  3. Standard deviation decreases, as individuals with the extreme trait decrease
22
Q

Why do different species look similar?

A
  1. Live in a similar environment
  2. Have similar selection pressures
  3. Similar alleles will have the selective advantage
  4. Produces similar/same proteins and therefore have similar characteristics
23
Q

What is as hierarchy?

A
  1. Smaller groups arranged within larger groups
  2. No overlap between groups
24
Q

What are the modern and accurate classification methods?

A
  1. DNA sequence
  2. mRNA sequence
  3. Amino acids sequence
  4. Immunological - comparing similarity in self-antibody shape
25
Q

What are the farming techniques that reduce biodiversity?

A
  1. Destruction of hedgerows
  2. Selective breeding
  3. Monocultures
  4. Over-grazing
  5. Filling in ponds and draining wetlands
26
Q

What is the index of diversity

A
  1. A measure of species diversity
  2. A calculation to measure the relationship between the number of species in community and the number of individuals in each species
27
Q

What does ‘N’ represent in the index of diversity

A

Total number of organisms of all species

28
Q

What does the ‘n’ represent in the index of diversity

A

Total number of organisms of a particular species

29
Q

What does the ‘D’ represent in the index of diversity

A

Simpson’s diversity index