Genetics Flashcards

(32 cards)

1
Q

Describe the human genome?

A

the complete set of nuclei acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule food within individual mitochondria

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2
Q

Define chromosome

A

a thread-like structure of nuclei acids and protein found in the nucleus of most living cells, carrying genetic information in the forms of genes

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3
Q

Define locus

A

the position of a gene along the chromosome

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4
Q

Define gene

A

a length of DNA encoding the information to make a protein

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5
Q

Define DNA

A

a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes - it is the carrier of genetic information

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6
Q

Explain the structure of chromosome

A
  • each is a single molecule of DNA, tightly packaged by proteins with genres located at positions along the chromosome in a linear sequence
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7
Q

Describe the position of genes along the chromosomes

A

located at positions along the chromosome in a linear sequence

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8
Q

What are homologous chromosomes?

A

in our body cells each chromosome is paired i.e. forms a homologous pair - one paternal and one maternal - homologous chromosomes contain the same genes

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9
Q

What is a human karyotype?

A

the number and visual appearance of the chromosomes in the cell nuclei of an organism or species

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10
Q

What is the word for chromosome 1-22?

A

autosomes

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11
Q

What are X and Y chromosomes?

A

sex chromosomes

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12
Q

What are the female chromosomes?

A

XX

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13
Q

What are the male chromosomes?

A

XY

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14
Q

Define alleles

A

an allele is a version of a gene - X and Y have two alleles

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15
Q

Define ploidy

A

the number of sets of chromosomes in each cell

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16
Q

Define haploid

A

one set of chromosomes

17
Q

Define diploid

A

two sets of chromosomes

18
Q

Define mitosis

A

normal cell division, creating two genetically-identical daughter cells

19
Q

Define meiosis

A

reduction division in which each daughter cell receives one cope of each chromosomes

20
Q

Briefly explain the human life cycle

A
  • egg and sperm cells (haploid n=23)
  • ^ carry one copy of each chromosomes in their nucleus
  • at fertilisation, the egg and sperm cell nuclei fuse
  • the zygote (fertilised egg) therefore is diploid (2n=46)
  • ^ mean it has a copy of each haploid chromosome
21
Q

What percentage of 1st trimester miscarriages are caused by chromosomal abnormalities?

22
Q

What is a change in the number of chromosomes usually caused by?

A

usually an isolated occurrence

23
Q

What is a change in the structure of chromosomes usually caused by?

A

translocations, may be inherited

24
Q

How many newborns in 200 have multiple congenital abnormalities?

25
What chromosomal abnormality is trisomy 13?
patau's syndrome
26
What chromosomal abnormality is trisomy 18?
edward's syndrome
27
What chromosomal abnormality is trisomy 21?
down's syndrome
28
Chromosomal abnormalities are reliant on base-pairing rules. What are the pairs?
A-T | G-C
29
What is DNA replication?
the copying of genetic material whereby the two strands 'unzip' and rejoin using base-pairing rules in 2 identical DNA strands
30
During the 'flow of genetic info' otherwise known as transcription and translation, what occurs?
DNA which is made up of A, T, G, C are unziped to be RNA. mRNA goes in, makes a copy of the DNA where amino acids are created in order to make proteins
31
What input do proteins have in the human genome?
genes are used to direct the synthesis of proteins in the cells. the proteins take part in our development from the egg to the adult
32
Explain where variation in human genome occur?
variation in the sequence of the genes contribute to variations between individuals and some inherited genetic variants lead to genetic diseases e.g. cystic fibrosis