Genetics Flashcards

1
Q

What is DNA?

A

DNA is deoxyribonucleic acid.
It is found in the nucleus of the cells and is the genetic code molecule.

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2
Q

What are genes?

A

The basic physical and functional unit of heredity. Genes are each genetic instruction that codes for a particular trait and are made of DNA.

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3
Q

What is mitosis?

A

The process of your body making new cells through cell division.

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4
Q

What are cells and what are the two types?

A

The body is made up of two types of cells, sex cells and somatic cells.

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5
Q

What are sex cells?

A

Sex cells or gametes are produced by the cell division meiosis. There is only one chromosome from each pair.

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6
Q

What are somatic cells?

A

Cells of your body that aren’t sex cells.

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7
Q

What is a genotype?

A

Genetic instructions inherited from your parents at a particular gene locus.

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8
Q

What is a phenotype?

A

Characteristics that result from the expression of an organism’s genotype. Phenotypes depend on the genotype and the environment.

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9
Q

What are autosomes?

A

The 22 pairs of chromosomes present in both males and females. They are numbered in order of size.

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10
Q

What is homologous and non-homologous chromosomes?

A

Homologous chromosomes are when the members of the pair matching. Non-homologous are not matching.

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11
Q

What are sex chromosomes?

A

The sex chromosomes determine a person’s gender. Females have a pair of X chromosomes and males have an X and a Y.

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12
Q

What are karyotypes?

A

A person’s complete set of chromosomes.

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13
Q

What is trisomy and monosomy mutation?

A

Trisomy is when a chromosome is added to a pair, and monosomy is when a chromosome is missing.

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14
Q

What are nucleotides?

A

The repeating units that make up DNA. Each nucleotide has a sugar (deoxyribose), a phosphate, and a nitrogenous base.

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15
Q

What are the nitrogenous bases?

A

Adenine, thymine, guanine, and cytosine. Adenine pairs with thymine and guanine pairs with cytosine.

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16
Q

What are triplets in DNA code?

A

DNA is read three bases at a time, and each triplet codes for an amino acid. Amino acids join to produce proteins.

17
Q

What are proteins?

A

Proteins are complex molecules and do most of the work in cells. They are important to the structure, function, and regulation of the body.

18
Q

What is RNA?

A

RNA (ribonucleic acid) is a type of nucleic acid and is made up nucleotides. The sugar in RNA is ribose, and has the nitrogenous base of uracil instead of thymine. RNA is shorter and single stranded. The triplet in RNA is called a codon.

19
Q

What is the process of transcription?

A

The DNA is firstly unwound. When the relevant part of the DNA is exposed, a copy of the sequence is produced in the form of messenger RNA (MRNA). The DNA then rewinds. The mRNA passes through the nuclear pore into the cytoplasm of the cell. It takes the proteins instruction message to ribosomes, found on the rough endoplasmic reticulum or free floating in the cytosol.

20
Q

What is translation?

A

When the mRNA reaches the ribosome, the ribosome and transfer RNA (tRNA) are involved in translation. The tRNA, located in the cytosol, collects and transfers the appropriate amino acid to match the codon of the mRNA. The amino acids form together to form proteins.

21
Q

Where are genes located?

A

A gene is a segment of double stranded DNA containing information for the production of a particular protein or function. The position on a chromosome taken by a gene is its locus.

22
Q

What is diploid and haploid?

A

Somatic cells have chromosomes in pairs, called diploid. Sex cells are haploid, because they have only one set of chromosomes.

23
Q

What is the process of meiosis?

A

The process of going from diploid to haploid. A parent cell undergoes meiosis to form daughter cells.

24
Q

How does genetic variation occur during meiosis?

A

Independent assortment - chromosomes can line up in many different combinations during meiosis.
Crossing over - one chromosome can swap the same section with another chromosome.

25
Q

What is inheritance?

A

The passing on of characteristics from one generation to the next.

26
Q

What are alleles?

A

Alternate forms of a gene for a particular characteristic, found at a particular locus on a specific chromosome.

27
Q

What are dominant and recessive genes?

A

Fertilisation results in two alleles for each gene locus, a capital letter denotes a dominant allele, which is always expressed, and recessive genes are only expressed with the absence of dominant alleles.

28
Q

What is homozygous and heterozygous?

A

Homozygous is when the alleles are the same (BB or bb), and heterozygous are when they are mixed, (Bb).

29
Q

What is a carrier?

A

Refers to someone who is heterozygous for a particular trait and carries the allele for the recessive gene.

30
Q

What is the monohybrid ratio?

A

The phenotypic ratio of different types of individuals occurring in the F2 generation of the monohybrid cross.

31
Q

What are the rules for a punnet square?

A

For dominant/recessive inheritance, use a capital letter for the dominant trait, and lowercase letter for recessive. Sex chromosomes are used when looking at an X-linked trait.

32
Q

How do mutations occur?

A

When a mistake is made in the replication process of DNA.

33
Q

What are mutations?

A

Changes to DNA sequence at the gene or chromosomal level.

34
Q

What is spontaneous and induced mutation?

A

Spontaneous is when a cause cannot be identified. Induced is when a cause can be identified.

35
Q

What is a mutagen?

A

A mutagen is a factor that triggers mutations - UV Radiation, nuclear exposure, x-rays.

36
Q

What are point mutations?

A

When the DNA code is not followed exactly, resulting in:
- substitution of a different nucleotide,
- deletion of a nucleotide,
- insertion of a nucleotide,
- inversion of two nucleotides.