Biology Flashcards

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1
Q

What is an allele?

A

Alleles are variations of a gene

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2
Q

What is a dominant allele?

A

The allele that is always SEEN

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3
Q

What is a recessive allele?

A

The allele that is hidden

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4
Q

What is dominant allele represented by?

A

Capital letters

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5
Q

What is a recessive allele represented by?

A

Lowercase letters

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6
Q

When are dominant alleles seen?

A

ALWAYS

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7
Q

When are recessive alleles seen?

A

When there are 2 recessive alleles OR when there are NO dominant alleles

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8
Q

What is a genotype?

A

A genotype is an individual’s genetic makeup. (Alleles)

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8
Q

What is a phenotype?

A

A phenotype is what an individual looks like

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9
Q

What does homozygous mean?

A

It means an individual has TWO identical alleles

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10
Q

What does heterozygous means?

A

It means that an individual has two different alleles

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11
Q

What does a Punnett square show?

A

The percentage chance of an offspring’s phenotype and genotype

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12
Q

Is “B’ dominant or recessive?

A

Dominant

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13
Q

Is “f” dominant or recessive?

A

Recessive

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14
Q

Is BB homozygous or heterozygous?

A

Homozygous

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15
Q

Is Mm homozygous or heterozygous?

A

Heterozygous

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16
Q

R is Red and r is White that phenotype is Rr?

A

Red

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17
Q

R is Red and r is white. What phenotype is RR?

A

Red

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18
Q

What sex chromosomes represent a male

A

XY

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19
Q

What sex chromosomes represent a female

A

XX

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20
Q

IF a disease is recessive. Is this male affected, unaffected or a carrier? XbY

A

Affected

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21
Q

If a disease is recessive. Is this male affected, unaffected or a carrier? XBY

A

Unaffected

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22
Q

If a disease is recessive. Is this female affected, unaffected or a carrier? XbXb

A

Affected

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23
Q

If a disease is recessive. Is this female affected, unaffected or a carrier? XBXb

A

Carrier

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24
Q

If a disease is recessive. Is this female affected, unaffected or a carrier? XBXB

A

Unaffected

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25
Q

What does a square represent in a pedigree?

A

Male

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26
Q

What does a circle represent in a pedigree?

A

Female

27
Q

What does a shaded shape mean in a pedigree?

A

A person affected by a disease

28
Q

What does an unshaded shape mean in a pedigree?

A

A person that is unaffected OR a carrier

29
Q

If a line connects two shapes in a pedigree what does this mean>

A

They matedh

30
Q

What is a mutation?

A

A permanent change in the DNA sequence

31
Q

What do mutations create in a population?

A

New alleles OR new variations of genes

32
Q

What is a gene pool?

A

The sum of different alleles in a population

33
Q

What is allele frequency?

A

The frequency/percentage of one allele in the population

34
Q

What is a mutagen?

A

A substance that increases the rate of mutationsW

35
Q

What are 3 main mutations?

A

Radiation, Chemicals and UV light

36
Q

What is an example of a radiation mutagen?

A

X-rays

37
Q

What is an example of a chemical mutagen?

A

Tobacco

38
Q

What is an example of a UV mutagen?

A

The sun’s rays

39
Q

What is Co-dominance?

A

When TWO dominant alleles are both expressed in an individual. This creates patches in coloring. Eg. White dog + brown dog = Brown and white spotted dog

40
Q

What is a carrier?

A

A person who does not show a disease/have a disease… however, carries it in their DNA and can pass it onto their children.

41
Q

What are the 3 stages of natural selection?

A
  1. Variation
  2. Selection pressure
  3. Adaptation
42
Q

What are the 3 stages of speciation

A
  1. Variation
  2. Isolation
  3. Selection
43
Q

What is variation>

A

The amount of different alleles in a population. Eg. Humans can have brown eyes, blue eyes, green eyes.

44
Q

What is a selection pressure

A

A change in the environment that causes an allele to have an advantage. EG. predation

45
Q

What is adaptation?

A

When the “fitter” allele in a population becomes more common and allows organisms to be BETTER adapted to survive in their environment.

46
Q

What is isolation?

A

The separation of one population into two or more for a long period of time preventing them from mating with other populations.

47
Q

What are the 2 types of isolation?

A
  1. Geographical
  2. Climatic
48
Q

What is geographical isolation?

A

When a land feature separates individuals in a population. Eg. Temperature

49
Q

What is an example of speciation?

A

-Squirrel population in America had varying arm lengths.
-The grand-canyon isolated/separated the population into 2 groups.
-The south side squirrel population adapted to tall trees and got longer arms.
-The north side squirrel population adapted to flat rocky surface and got short arms for running fast.
-Two new species formed from one.

50
Q

What is an example of natural selection?

A

-The peppered moth has 2 variations: dark and light.
Coal production coated trees with black soot.
-The dark moths camouflaged with the black soot avoiding predators.
-Light moths were eaten.
-The frequency of dark moths became more common.
-Dark coloured moth are better adapted to survive in their environment.

51
Q

What is artificial selection?

A

When humans deliberately breed organisms to get desirable traits in offspring.

52
Q

What is crossbreeding?

A

Breeding two organisms with different desirable traits to combine them and get both in the offspring.

53
Q

What is inbreeding?

A

Breeding related organisms together to emphasise a desirable trait in offspring.

54
Q

What is evolution?

A

The permanent change in allele frequency in a population

55
Q

What is the theory of evolution?

A

The theory that all organisms originate from a common name ancestor

56
Q

What 2 types of evolution are there?

A
  1. Convergent
  2. Divergent
57
Q

What is convergent evolution?

A

When two organisms have similar structure with the same function, NOT because of common ancestor. Due to common selection pressure (environment). EG. Fin or shar and dolphin

58
Q

What is an analogous structure?

A

A characteristic that 2 different species have for the same function, NOT because of common ancestor. Due to common selection pressure (environment).

59
Q

What is divergent evolution?

A

When two organisms have similar structure that have been adapted for different function, THese structures come from a common ancestor. EG. Forearm of cat and human

60
Q

What is a homologous structure?

A

A structure that is the same in multiple species however has different functions. These come from a common ancestor that now has NO function

61
Q

What is a vestigial structure?

A

A characteristic in an organism that they have from an ancestor that now has NO function

62
Q

What are 4 pieces of evidence supporting evolution?

A
  • Fossils
  • Embryo similarities
  • Comparative anatomy
  • DNA analysis
63
Q

How do fossils support evolution?

A

Finding fossils and using carbon dating to age them have provided an evolutionary timeline showing small changes in one species from their ancestors to current date.H

64
Q

How does embryology support evolution?

A

Vestigial structure in organisms suggests that they are passed on from ancestors and are no longer needed. EG. Wisdom teeth in humans have been from our herbivore ancestors

65
Q

How does DNA analysis support evolution?

A

Similarities in proteins in DNA suggest that different species are closely related. More similarities = more closely related.
Eg. Chimpanzees and humans share similarities in DNA.