Chapter 2 Flashcards

1
Q

Chromosomes

A

Most cells of the body have a full set of 46 chromosomes- tiny structures in the nucleus that contain genetic material. The gametes each have half that number- 23 chromosomes.

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2
Q

In vitro fertilization (IVF)

A

In vitro fertilization (IVF), involves mixing sperm and egg together in a laboratory dish and then placing a few of these eggs in the mother’s uterus.

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3
Q

Autosomes

A

The first 22 pairs of chromosomes are called autosomes, the chromosomes in each pair are about the same size.

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4
Q

Sex chromosome

A

The 23rd pair determines the sex of the child, these two are know as the sex chromosome. The chromosome labelled X is much larger than the chromosome labelled Y.

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5
Q

Deoxyribonucleic acid (DNA)

A

Each chromosome actually consists of one molecule of DNA.

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6
Q

Gene

A

Each group of nucleotide bases that provides a specific set of biochemical instructions is called a gene.

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7
Q

Genotype

A

The complete set of genes makes up a person’s heredity and is known as a person’s genotype.

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8
Q

Phenotype

A

Genetic instructions, in conjunction with environmental influences, produce a phenotype, an individual’s physical, behavioural,and physical features.

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9
Q

Alleles

A

Genes come in different forms which are known as alleles.

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10
Q

Homozygous/ Heterozygous

A

Sometimes the alleles in the pair of chromosomes are the same, which makes then homozygous. Sometimes the alleles differ, which makes then heterozygous.

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11
Q

Dominant/ Recessive alleles

A

Often one allele is dominant, which means that its chemical instructions are followed, whereas the instructions of the other, the recessive allele, are ignored.

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12
Q

Incomplete dominance

A

Sometimes one allele does not dominate another completely, a situation known as incomplete dominance. The phenotype that results often falls in between the phenotype associated with either allele.

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13
Q

Sickle-cell trait

A

Individuals with one dominant and one recessive sickle cell allele have sickle-cell trait. In most situations they have no problems, but when they are seriously short of oxygen they suffer a temporary, relatively mild form of the disease.

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14
Q

Huntington’s disease

A

Is a fatal disease characterized by progressive degeneration of the nervous system. Individuals who inherit do not show signs until adulthood making it difficult to detect. Cause by a dominant allele found on chromosome 4.

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15
Q

Hemophilia

A

A disorder in which the blood does not clot easily and suffered can bleed severely with even minor injury,the gene is carried on the X chromosome.

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16
Q

Down Syndrome

A

A genetic disorder that is caused by an extra 21 chromosome and results in intellectual disability.

17
Q

Behavioural genetics

A

Behavioural genetics is a branch of genetics that deals with inheritance of behavioural and psychological traits.

18
Q

Polygenic inheritance

A

Phenotypes often reflect the combined activity of many separate genes.

19
Q

Monozygotic twins

A

Identical twins are called monozygotic twins because they come from a single fertilized egg that splits in two.

20
Q

Dizygotic twins

A

Fraternal or dizygotic twins come from two separate eggs fertilized by two separate sperm.

21
Q

Reaction range

A

The range of phenotypes that the same genotype may produce in reaction to the environment where development takes place.

22
Q

Epigenesis

A

The continuous interplay between genes and multiple levels of the environment (from cells to culture) that drives development

23
Q

Methylation

A

Sometimes experiences change the expression of DNA. This process is known as methylation because the chemical silencer is a methyl molecule.

24
Q

Heritability coefficient

A

Estimates the extent to which differences between people reflect heritability.

25
Q

Niche-picking

A

The process of deliberately seeking environments that fit ones heredity is called niche-picking.

26
Q

Nonshared environmental influences

A

The environmental differences that make twins different.