Genetics Flashcards Preview

Biology > Genetics > Flashcards

Flashcards in Genetics Deck (100):
1

Adenine (A)

- Nitrogen containing base
- Found in RNA/DNA nucleotides

2

Alleles

- Alternative forms of a gene
- Most genes have two alleles (more are possible)

3

Antiparallel

- DNA
- One strand runs 5' to 3'
- Other runs 3' to 5'

4

Autosomes

- Chromosomes that are not sex chromosomes

5

Base

- Adenine, Thymine, Guanine and Cytosine
- Present in nucleotides of DNA/RNA
- Link DNA strands

6

Centromere

- Part of chromosome that attaches to spindle fibres
- Where two sister chromatids connect

7

Chromatid

- One of two copies of a chromosome
- Formed during S phase of interphase

8

Chromosome

- DNA strands coiled around histone proteins
- Carry hereditary information of cell (genes)

9

Complementary base pair

- Adenine paired to thymine
- Guanine paired to cytosine

10

Complete dominance

- Expression of only one phenotype in all heterozygous individuals

11

Cytosine (C)

- Nitrogen containing base
- Found in nucleotides of DNA/RNA

12

Diploid

- Having two sets of chromosome (2n)
- All somatic cells

13

DNA

- Deoxyribonucleic acid
- Made up of sequence of nucleotides
- Deoxyribose sugar, phosphate, and base
- Carrier of genetic information
- Found in chromosomes, mitochondria, and plastids

14

DNA sequencing

- Determination of sequence of bases in part of DNA
- Can be used to determine genome

15

Dominance

- Expression of one allele over another

16

Dominant phenotype

- Phenotype expressed in all heterozygous individuals

17

Double helix

- Shape of DNA molecule
- Two linear lengths of nucleotides twisting around each other

18

Epigenetics

- Study of molecular events that occur on DNA
- Do not alter DNA sequence, but change phenotype

19

Gene

- Section of DNA
- Contains instructions for making a protein
- Have specific locations on chromosome

20

Genome

- DNA in all chromosomes present in the nuclei of a normal cell
- Also includes DNA in mitochondria and chloroplasts

21

Genotype

- Two definitions
1) Total set of genes if an organism
2) Combination of alleles for a trait carried by an individual

22

Guanine (G)

- Nitrogen containing base
- Found in nucleotides of DNA/RNA

23

Haploid

- Contains one set of chromosomes
- Half the chromosomes of a diploid cell

24

Hemizygous

- Diploid cell with only one copy of a particular chromosome
- Human males hemizygotes because only one X chromosome

25

Hereditary

- Can be passed from parent to offspring

26

Heterogametic

- Different sex chromosomes
- Males, XY

27

Heterozygote/Heterozygous

- Different alleles for a gene

28

Histones

- Alkaline protein that arranges DNA into nucleosomes

29

Homogametic

- Same sex chromosomes
- Human females, XX

30

Homologous chromosomes

- Matching chromosomes
- Same genes on same loci

31

Homozygote/Homozygous

- Identical alleles at similar locus

32

Human Genome Project

- Project started in 1990 to determine human genome
- Completed in 2003

33

In vitro fertilisation (IVF)

- Fertilisation of ovum outside the body

34

Karyotype

- Visual depiction of number, size and shape of chromosome

35

Locus

- Site on chromosome where particular gene is located

36

Nucleosome

- Particle made of histone proteins
- DNA coiled around it

37

Phenotype

- Two definitions:
1) Observable character or trait of organism
2) Overall appearance of organism

38

Ploidy

- Number of full sets chromosomes in a karyotype
- Haploid or diploid most common

39

Polygene

- Multiple genes control one trait

40

Polygenic inheritance

- Inheritance of observable trait determined by many genes

41

Polypeptide

- Chain like molecule made of linked amino acids

42

Pre-implantation genetic diagnosis (PGD)

- Genetic testing done before fertilised egg is implanted
- Determine genetic errors that may cause disorders

43

Protein

- Organic compound made of one or more chains of amino acids

44

Purines

- Adenine and guanine

45

Pyrimidines

- Thymine, cytosine and uracil

46

Recessive phenotype

- Phenotype only shown by homozygous people

47

Reprogramming

- Conversion of one cell type into a different cell type

48

Sex chromosome

- Chromosome involved in determining sex
- In humans, X and Y

49

Somatic cell

- Any cell except those that give rise to gametes
- In mammals, diploid

50

Thymine (T)

- Nitrogen containing base
- Found in DNA and RNA

51

Trait

- Particular characteristic or feature of an organism

52

Amplify

- Use polymerase chain reaction (PCR) to make many copies of a piece of DNA

53

Antigen

- Substance that stimulates antibody production.
- Can bind with an antibody produced by immune system

54

Biochemical testing

- Testing for amount or activity of certain proteins
- Used to detect abnormalities
- Abnormality may be indicator of genetic disorder

55

Carrier

- Organism that has allele for a trait, but does not express it.
- Recessive allele.
- Can pass on to offspring.

56

Chiasma

- Point of crossing over of non-sister chromatids

57

Co-dominance

- Phenotype resulting from expression of both alleles.
- Heterozygote.

58

Cross

- Intentional breeding of two genetically different organisms.
- Offspring inherit genetic material from each parent

59

Crossing over

- Exchange of chromosomal material between non-sister chromatids.

60

Cytogenetic testing

- Genetic testing method used to find chromosomal abnormalities

61

Dihybrid cross

- Cross between homozygous individuals that exhibit two phenotypes

62

DNA amplification

- Production of a large number of copies of a DNA fragment

63

DNA polymerase

- Enzyme that catalyses creation of new DNA strand in DNA replication

64

DNA profiling

- Identification of individual by characteristics of their DNA

65

DNA sequencing

- Determination of sequence of bases in fragment of DNA

66

Dominant

- Expression of one allele over another

67

Fluorescence-in situ hybridisation (FISH)

- Method used in genetic testing
- Identifies specific location of gene or allele.
- Detects changes in chromosome structure

68

F1 generation

- Generation consisting of offspring of a cross between members of parental generation

69

F2 generation

- Offspring of a cross between members of F1 generation

70

Gel electrophoresis

- Technique used to separate fragments of DNA or proteins based on size

71

Gene mapping

- Determination of location of genes and distance between them on chromosome

72

Genetic screening

- Genetic testing of a large number of individuals or embryos.
- Used to identify carriers for a particular disease

73

Genetic testing

- DNA analysis to determine genetic status of individual or embryo.

74

Genome

- DNA in one full set of chromosomes present in nuclei of normal cell of a species.
- Also includes DNA in mitochondria and chloroplasts

75

Heterogametic

- Different sex chromosomes (E.g human males, XY)

76

Heterozygous

- Diploid individual with different alleles for particular gene

77

Homogametic

- Two similar sex chromosomes (E.g human females, XX)

78

Incomplete penetrance

- Some individuals carrying allele for trait do not express trait

79

Law of Independent Assortment

- Mendel's second law
- Individual inherited traits assort independently
- Occurrence of of trait not affected by occurrence of another trait

80

Law of Segregation

- Mendel's First Law
- Alleles separate during gamete formation
- Randomly unite at fertilisation

81

Linkage

- Tendency for two or more genes on same chromosome to be inherited together because they are in a similar position.
- May be separated by crossing over

82

Locus

- Site of a chromosome where a particular gene is located

83

Molecular genetic testing

- Genetic testing method used to identify single genes or short pieces of DNA

84

Monohybrid cross

- Cross between individuals that have different alleles for a specific gene.
- Study inheritance of one characteristic

85

Mutant

- Individual with phenotype different from wild type (phenotype of wild population)

86

Parental type

- Gamete that has same alleles that parent has.
- Also called parental gamete

87

Pedigree analysis

- Determination of pattern of inheritance of trait using a pedigree chart

88

Penetrance

- How much a phenotype is expressed among individuals with the genotype for that phenotype

89

Polymerase chain reaction (PCR)

- Technique used to create millions of identical copies of a DNA segment quickly

90

Pre-implantation genetic diagnosis (PGD)

- Genetic testing done before implantation of fertilised egg
- Check to see if there are any genetic abnormalities

91

Primer

- Short, synthetic segment of DNA
- Specify starting and finishing points for DNA replication

92

Progeny

- Offspring or descendants of an organism

93

Recessive

- Trait or phenotype whose appearance is subordinate to a dominant trait

94

Reciprocal cross

- Male of strain A crossed with female of strain B
- Female of strain A crossed with male of strain B

95

Recognition site

- Short segment of DNA recognised by restriction enzyme
- Different enzymes recognise different sites

96

Recombinant gametes

- Gametes carrying combination of alleles not observed in parents
- Come from crossing over

97

Sex-limited inheritance

- Trait only expressed by one sex, even if both sexes carry the gene

98

Sex-linked inheritance

- Inheritance related to genes that occur on sex chromosomes
- X and Y chromosomes

99

Spontaneous mutation

- Naturally occurring random change in DNA

100

Test cross

- Individual with dominant phenotype crossed with individual of recessive phenotype
- Used to identify if dominant phenotype is homozygous or heterozygous