genetics Flashcards

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1
Q

What contains the DNA?

A

chromosomes in nucleus

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2
Q

What is a gene?

A

A short section of DNA that codes for protein

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3
Q

How many pairs of chromosomes do you have in cells?

A

23 pairs from both your mum & dad
46 in total.
(sex cells are the exception, they have half so total 23)

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4
Q

describe the first stage of mitosis

A

Interphase : chromosomes are copied

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5
Q

describe the second phase of mitosis.

A

Prophase : spindle fibres form in the cell and nuclear membrane starts to disappear

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6
Q

describe the third stage of mitosis

A

Metaphase: chromosomes line up in the middle

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7
Q

describe the fourth stage of mitosis

A

Anaphase : chromosomes pulled apart by spindles

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8
Q

describe the 5th stage of mitosis

A

Telophase: nuclei start to reform

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9
Q

describe the last stage of mitosis

A

cytokinesis : a cell membrane divides the cells

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10
Q

Describe the structure of DNA

A

DNA is a polymer made of sub units called nucleotides, with a double helix made of 2 strands of complimentary base pairs. The base pairs are A+T, C+G. These are joined by hydrogen bonds and down the double helix is a sugar phosphate backbone.

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11
Q

what does homozygous mean?

A

when both alleles for a gene are the same

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12
Q

what does heterozygous mean?

A

when it’s the alleles for a gene are different

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13
Q

what’s a genotype?

A

all the alleles in an organism

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14
Q

what’s a phenotype?

A

the observable physical characteristic

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15
Q

what’s an allele?

A

A version of a gene

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16
Q

what’s a chromosome?

A

One enormously long coiled DNA molecule. Contains many genes.

17
Q

why are gametes haploid cells?

A

they only contain half of the genetic information of a normal cell

18
Q

chromosomes in meiosis line up randomly. what does that mean?

A

randomly distributed when pulled apart (maternal and paternal chromosomes) so DNA in both cells when they slip is different