genes and inheritance

Question 1

DNA

Answer 1

(deoxyribose nucleic acid) a double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival

Question 2

chromosomes

Answer 2

the structure made of protein and nucleic acids that carries genetic information

Question 3

autosomes

Answer 3

one of the numbered chromosomes, as opposed to the sex chromosomes.

Question 4

somatic cells

Answer 4

any cell that is not a reproductive cell (such as sperm and egg cells). Somatic cells are diploid (2n), meaning they contain two sets of chromosomes – one inherited from each parent

Question 5

sex cells

Answer 5

reproductive cells or gametes

Question 6

diploid

Answer 6

cells or organisms that have two sets of chromosomes (2n)

Question 7

haploid

Answer 7

describes a single set of chromosomes (n)

Question 8

genotype

Answer 8

consists of two letters that represent a genes allele pair that results in a phenotype

Question 9

phenotype

Answer 9

obervable traits resulting from how ones genes are expressed

Question 10

homozygous

Answer 10

having identical alleles for the same gene on homologous chromosomes

Question 11

heterozygous

Answer 11

having different alleles for the same gene on homologous chromosomes

Question 12

genome

Answer 12

the complete set of DNA contained within an organism’s chromosomes

Question 13

carrier

Answer 13

an organism that has inherited a copy of a recessive allele for a genetic trait but does not display the trait due to it being masked by the presence of a dominant allele

Question 14

autosomal dominant

Answer 14

the variant of a gene that masks the effect of a recessive allele of the same gene on a homologous chromosome, and is always expresseed

Question 15

autosomal recessive

Answer 15

the variant of a gene that is masked by a dominant allele on
a homologous chromosome, only expressed if there is two copies

Question 16

test cross

Answer 16

when an individual expressing the dominant phenotype but with an unknown genotype is crossed with a homozygous recessive individual. The results indicate whether the individual with the dominant phenotype is homozygous dominant or heterozygous

Question 17

codominance

Answer 17

a pattern of dominance where both alleles from the genotype of a heterozygous individual are dominant and expressed in the phenotype of that organism

Question 18

incomplete dominance

Answer 18

a pattern of dominance where neither allele from the genotype of a heterozygous individual is dominant and both are expressed in an intermediate phenotype

Question 19

loci

Answer 19

the fixed position on a chromosome where a particular gene is located

Question 20

DNA methylation

Answer 20

methyl group tags certain DNA, either activating and repressing genes

Question 21

epigenetic

Answer 21

external factors that influence how a gene is expressed either boost or inhibit the transcription of genes into proteins.

Question 22

karotype

Answer 22

a visual representation of an individual’s entire genome organised into homologous pairs

Question 23

somatic cell nuclear transfer

Answer 23

the transference of a somatic cell nucleus into an enucleated egg cell

Question 24

somatic cell nuclear transfer process

Answer 24

enucleation - the removal of the nucleus from a donated egg cell to produce an enucleated egg cell
extraction - the donated somatic cell nucleus is extracted
insertion - the somatic cells nucleus is inserted into the enucleated egg cell
development - the cell begins to divide and develop into an embryo, which is implanted into surrogate mother

Question 25

embryo splitting

Answer 25

fertilised - egg cell removed from donor
eggs are fertilised in a test tube

early embryo split - Once zygote has divided, the extended coat which promotes cell division is removed and two cells separate

split embryos implanted in surrogate mother - each cell is given an artificial coating which promotes division and are implanted in surrogate mother