Genetics Definitions

Question 1

chromosomes

Answer 1

threads made up of 40% DNA and 60% protein
found in the nucleus
carry genetic info in the form of genes

Question 2

gene

Answer 2

a section of DNA that codes for the production of a protein
unit of inheritance
located on DNA of a chromosome

Question 3

homologous pair

Answer 3

two chromosomes of equal length with the same sequence of genes

Question 4

heredity

Answer 4

the passing on of features from parents to offspring by means of genes

Question 5

gene expression

Answer 5

the way in which genetic information is decoded from a gene and used to make a protein

Question 6

DNA

Answer 6

deoxyribonucleic acid

a nucleic acid that carries and passes on genetic info in the nucleus of a cell

Question 7

RNA

Answer 7

ribonucleic acid
a nucleic acid that carries info of an amino acid sequence from the genes to ribosomes in the cytoplasm and uses this info to form functioning proteins

Question 8

non coding dna

Answer 8

does not code for a protein

Question 9

genetic code

Answer 9

sequences of bases in DNA that code for the production of a specific protein

Question 10

triplet/codon

Answer 10

sequence of three bases that code for an amino acid

Question 11

anticodon

Answer 11

sequence of three bases on tRNA that are complementary to the sequences of three bases on mRNA

Question 12

transcription

Answer 12

copying a sequence of bases from DNA to mRNA with the aid of RNA polymerase in the nucleus of the cell

Question 13

translation

Answer 13

synthesis of proteins by forming chains of amino acids in the ribosome with the help of mRNA, rRNA and tRNA

Question 14

DNA profile

Answer 14

making and examining a pattern of bands from the DNA of one person which can be compared with the DNA profile of another person

Question 15

genetic screening

Answer 15

testing for the presence of a specific or altered gene

Question 16

species

Answer 16

a group of similar organisms capable of interbreeding with each other and producing fertile offspring

Question 17

variation

Answer 17

differences between members of the same species

causes : mutation, sexual reproduction

Question 18

acquired variation

Answer 18

not inherited
learned or developed in life
eg playing a musical instrument

Question 19

inherited variation

Answer 19

controlled by genes

eg blood type

Question 20

mutation

Answer 20

a spontaneous change in the amount or structure of DNA

Question 21

mutagen

Answer 21

agents that cause mutation

eg X Rays, gamma radiation, cigarette smoke

Question 22

chromosome mutation

Answer 22

change in structure or number of chromosomes

eg downs syndrome

Question 23

gene mutation

Answer 23

a change in a single gene

eg cystic fibrosis

Question 24

evolution

Answer 24

inheritable change within a population in response to a change in the environment over time, giving rise to a new species

Question 25

natural selection

Answer 25

members of a species with genetic traits that allow them to be better adapted to survive in their environment, will reproduce and pass these on to following generations

Question 26

speciation

Answer 26

the production of a new species as a result of evolution

Question 27

genetic engineering

Answer 27

artificial manipulation of genes

Question 28

gamete

Answer 28

sex cell capable of fusion

Question 29

fertilisation

Answer 29

the fusion of the egg and sperm nuclei to form a diploid zygote

Question 30

somatic cell

Answer 30

all other body cells that are not sex cells (diploid)

Question 31

allele

Answer 31

different forms of the same gene

Question 32

locus

Answer 32

position of a gene on a chromosome

Question 33

homozygous

Answer 33

two alleles for a trait are the same

Question 34

pure breeding

Answer 34

homozygous

Question 35

hybrid

Answer 35

heterozygous

Question 36

dominant

Answer 36

where one alleles effect masks the effect of another

Question 37

recessive

Answer 37

an alleles effect is only expressed when in the homozygous condition

Question 38

genotype

Answer 38

genetic makeup

Question 39

phenotype

Answer 39

physical make up

Question 40

incomplete dominance

Answer 40

neither allele masks the effect of another

Question 41

linkage

Answer 41

genes for different traits are located on the same chromosome gives rise to less variation

Question 42

sex linkage

Answer 42

a characteristic controlled by a gene on a sex chromosome | eg colour blindness

Question 43

pedigree study

Answer 43

a diagram showing the genetic history of a group of related organisms

Question 44

monohybrid cross

Answer 44

study of one characteristic

Question 45

dihybrid cross

Answer 45

study of two characteristics

Question 46

non nuclear inheritance

Answer 46

inheritance of DNA through mitochondria or chloroplasts | from mother

Question 47

genetics

Answer 47

the study of how traits are passed from parent to offspring