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Biology > Chaoter 6.1 > Flashcards

Chaoter 6.1 Flashcards

1
Q

Give an example of an visible genetic difference

A

-Coat colour of llama

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2
Q

Give an example where the genetic difference isn’t visible

A

-Owls

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3
Q

What is genetic diversity?

A

-variation or inherited genetic difference in a species

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4
Q

Give 2 facts about genetic diversity.

A
  • result of sexual reproduction

- randomly sorts, shuffles DNA

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5
Q

What is diploid number?

A

-Body cell that has two sets of chromosomes

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6
Q

What is the human diploid number?

A

46 (23x2)

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7
Q

How does mitosis help diploids?

A

-Makes sure diploid number always stays the same and genetic information contained in body always remain the same unless mutation

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8
Q

Why does genetic diversity within a species is more advantage than a species with no genetic diversity?

A

Organisms will have combinations of genes from parents, allow it to cope with changes in environment

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9
Q

What is haploid number?

A

One set of 23 chromosomes from female parent and one set of 23 chromosomes from their male parent

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10
Q

What are haploid chromosomes carried in

A

Gametes

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11
Q

What are gametes?

A

Specialized cells necessary for reproduction

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12
Q

What are male gametes called

A

Sperm

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13
Q

What are female gametes called

A

Egg cells

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14
Q

What is fertilization

A

The process which an egg cell is penetrated by a species cell and haploid genetic information from sperm and egg cells combine

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15
Q

What is a zygote

A

New diploid cell formed by fertilization,

Half chromosomes from female half from male

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16
Q

What is embryo

A

The stage of a multicellular organism following fertilization

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17
Q

What is the difference between a zygote and embryo

A

Zygotes undergoes mitosis

Cell division developes into embryo

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18
Q

What is meiosis

A

Process that produces sperms and eggs

19
Q

Name the steps of meiosis

A

Meiosis 1:

  • Prophase 1
  • Metaphase 1
  • Anaphase 1
  • Telophase 1
  • interkinesis

Meiosis 2:

  • Prophase 2
  • Metaphase 2
  • Anaphase 2
  • Telophase 2
  • Cytokinesis
20
Q

Why is meiosis important?

A

Without meiosis, joining of sperm and egg cell during fertilization would produce offspring with two times original number of chromosomes

21
Q

What are the homologous chromosomes

A

A pair of matching chromosomes

22
Q

Describe the steps of meiosis 1

A

Prophase 1: homologous chromosomes pair up, crossing over

Metaphase1: homologous chromosomes pair up at equator

Anaphase1: homologous chromosomes separated by SPINDLE
FIBRES, independent assortment

Telophase1: one chromosome from
homologous pair at each pole of cell

Interkinesis: stage between cell division, cell grows and makes protein NO REPLICATION OF DNA

23
Q

Describe the steps of meiosis 2

A

Prophase 2: one chromosome of homologous pair in each cell

Metaphase 2: chromosomes from single line across middle

Anaphase 2: sister chromatids move to opposites poles of cells

Telophase 2: spindle fibres begin to disappear, nuclear membrane forms around each set chromosomes

Cytokinesis: two daughter cells seperated

24
Q

What is the result of meiosis 1

A

-2 diploid cells, 46 chromosomes

25
Q

What is the result of meiosis

A

-4 diploids, 23 chromosomes

26
Q

What is crossing over?

A

Parts of non sister chromatids “cross over” each other and exchange segments of DNA

27
Q

What is the result of crossing over?

A
  • Each chromosomes picks up new genetic information from the other
  • multiple crossovers can occur between 2 chromosomes, can creat infinite genetic possibilities
28
Q

What is independent assortment

A

-homologous pairs of chromosomes seperated and sort themselves into daughter cells; shuffling of genes

29
Q

What happens during independent assortment

A

-homologous pairs of chromosomes seperate at equator and move towards opposite poles of cell

30
Q

What is gamete formation in males

A
  • Meiosis 1 occurs and produces 2 cells, followed by meiosis 2 if there’s enough nutrients for cell division
  • 4 cells within cytoplasm and organelles equally divide among them
31
Q

What is the gamete formation in females

A

Meiosis 1 occurs and produces 2 egg cells, unequal division of cytoplasm and organelles
After meiosis 2, threes egg cells disintegrate, one large egg cell remains most of cytoplasm, available for fertilization

32
Q

Describe chromosome mutations in meiosis

A
  • parts of chromosome can be inverted,
  • parts of chromosome can be duplicated
  • parts of chromosome can be lost or deleted
  • parts of chromosome came move to a different region in the chromosome
33
Q

When do chromosome mutations occur?

A

-cells exposed to mutagens (radiations or chemicals)

34
Q

Describe mutations in meiosis 1 and meiosis 2

A

Meiosis 1: homologous chromosomes fail to seperate

Meiosis 2: sister chromatids fail to seperate

35
Q

What is the result of mutations

A

-one gamete will have two copies of chromosomes, other will have no copy of that chromosome

36
Q

What is a karotype?

A

Photograph that shows number of chromosomes a person has, the size, shape

37
Q

What is karotypes for

A

Used to diagnose genetic disorders

38
Q

How are karotypes prepared?

A

Cutting and pasting chromosomes from body cells during mitosis

39
Q

How are homologous chromosomes identified (karotypes)

A

-paired by size, centromere location and banding patterns

40
Q

What is a syndrome and give an example.

A

Particular disease or disorder with a specific group of symptoms that occur together

Down syndrome

41
Q

Describe people diagnosed with Down syndrome

A
  • characteristic facial features, -
  • shortie stature
  • prone to develope heart defects and disease (Alzheimer’s, leukaemia)
42
Q

What percent of people are caused by extra 21 chromosomes

A

95%

43
Q

What’s is sexual reproduction

A
  • Requires 2 parents

- produces offspring genetically different from parent or any member of the same species m

Biology (18 decks)

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