Chapter 9 Glossary terms Flashcards

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1
Q

Gonads

A

Organs that produce gametes

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2
Q

Ovaries

A

Organ in females that produce eggs, ova

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3
Q

Testes

A

Organ in males that produces sperm

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4
Q

Gametes

A

Egg, sperm - haploid cells which fuse during fertilisation in organisms that reproduce sexually

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5
Q

Zygote

A

first diploid cell formed after the fusion of two gametes

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6
Q

Fertilisation

A

Fusion of a male and female gamete

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7
Q

Germline cells

A

Specialised diploid cells found in the gonads that can undergo meiosis

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8
Q

Somatic cells

A

Diploid body cells. All body cells except gametes

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9
Q

Diploid cells

A

Cells with two sets of chromosomes (2n), one set derived from each parent. In humans the diploid number is 46

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10
Q

Haploid cells

A

Cells with one set of chromosomes (n). These cells are produced by meiosis. In humans the haploid number is 23

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11
Q

Gene

A

A section of DNA that codes for a protein, basic unit of heredity.

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12
Q

Allele

A

Alternative form of a gene

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13
Q

Genome

A

Al of the genes in a cell. Not all genes are switched on in any cell, but all genes are present. Every cell has the same genome.

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14
Q

Chromosome

A

Threadlike structures made up of DNA and protein. Only visible during cell division.

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15
Q

Chromatin

A

Chromosomes when not in mitosis or meiosis. Chromatin are made up of DNA and protein

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16
Q

Autosome

A

Any chromosome other than sex chromosomes. Humans have 44 autosomes

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17
Q

Sex chromosomes

A

Chromosomes that determine gender. In humans there are 2 sex chromosomes. Female: XX Male: XY

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18
Q

Homologous pairs of chromosomes

A

Chromosomes that are matched, one set derived from the mother and the other from the father. Important for successful meiosis producing viable gametes. Each pair carry genes controlling the same trait.

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19
Q

Chromatid

A

A copy of a duplicated chromosome, joined to the other copy by the centromere. Required for cell division and is produced in the S phase of the cell cycle.

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20
Q

Karyotype

A

a diagram of the chromosomes, arranged in order of size, position of the centromere, and sex chromosomes displayed together.

21
Q

Binary Fission

A

Bacterial (proaryotic) cell division where one cell divides into 2 identical daughter cells

22
Q

Mitosis

A

Cell division for growth and repair of eukaryotic cells where one diploid cell divides into 2 genetically identical daughter cells

23
Q

Meiosis

A

Cell division for the production of gametes, where one specialised diploid cell can produce 4 genetically different haploid cells.

24
Q

Interphase

A

cell replication. the chromatids replicate to make a chromosome

25
Q

prophase

A
  • chromosomes become visible
  • centrioles move to opposite poles of the cell
  • nuclear membrane disintegrates
26
Q

Metaphase

A
  • spindles fibres attach to chromosomes
  • chromosomes line up along the equator
    ‘M’ is for middle
27
Q

Anaphase

A
  • chromatids are pulled apart by the spindle fibres, forming 2 sets of chromosomes
  • ‘A’ is for apart
28
Q

Telophase

A
  • nuclear membrane forms around the new set of chromosomes
29
Q

Cytokinesis

A
  • the division of the cytoplasm that follows mitosis

- new cells are formed

30
Q

Mitosis inputs

A

1 diploid cell (2 sets of chromosomes)

31
Q

Mitosis outputs

A

2 diploid daughter cells, genetically identical to parent cells

32
Q

Meiosis inputs

A

1 specialised diploid cell in testes/ ovaries

33
Q

Meiosis outputs

A

4 haploid cells, genetically different gametes

34
Q

mitosis advantages

A
  • If the conditions are suitable and stable (i.e. the environment) then this organism can produce many genetically identical offspring. Well suited to the environment.
  • No need for a mate
35
Q

mitosis disadvantages

A

if environmental conditions change, then the whole species is at risk of extinction. (as they are genetically identical)

36
Q

meiosis advantage

A

genetically different offspring (due to gametes produced by meiosis from 2 genetically different parents) therefore a species may be more likely to survive changing environments.

37
Q

meiosis disadvantage

A

You have to have a mate.

38
Q

crossing over

A

in prophase 1, homologous pairs can exchange genetic material resulting in genetically different gametes.

39
Q

Independent assortment of chromosomes

A

the separation of one homologous pair has no influence on the separation of another homologous pair resulting in the mixing of maternal and paternal chromosomes in gametes.

40
Q

Aneuploidy

A

resulting in one chromosome too few or one chromosome too many. It is caused by the non-disjunction of homologous chromosomes

41
Q

non-disjunction

A

is when a pair of chromosomes fails to disjoin or segregate so that 2 copies of a chromosome are present in the gamete instead of usually one copy

42
Q

Cell cycle

A
  • G1, S, G2 -> interphase
  • mitosis = nuclear division
  • cytokinesis = cytoplasmic division
43
Q

Gap 1

A
  • cell growth, the cell is functioning, producing proteins. -> some of these proteins will be enzymes necessary for DNA replication
44
Q

Synthesis

A

DNA replication occurs here in readiness for mitosis

45
Q

Gap 2

A

Continued cell growth and producing proteins, necessary for mitosis

46
Q

how many autosomes are there in a human ovum

A

22

47
Q

how many chromosomes in a human sperm

A

23

48
Q

Are sex chromosomes present in somatic cells

A

Yes