unit 5

Question 1

genome

Answer 1

an entire set of genetic material of an organism

Question 2

DNA

Answer 2

chemical all our genetic material is made of inside the nucleus of a cell. It’s a polymer with a ‘double helix’ structure

Question 3

gene

Answer 3

a section of DNA that codes for production of a characteristic

Question 4

chromosomes

Answer 4

thread like structure found in nucleus of a cell made of DNA and contains genes

Question 5

allele

Answer 5

different version of the same gene- codes for different version of characteristic

Question 6

phenotype

Answer 6

physical characteristics of organism

Question 7

geneotype

Answer 7

the genes present for a trait

Question 8

dominant alleles

Answer 8

a version of a gene where only one copy is needed for it to be expressed 

Question 9

recessive allele

Answer 9

a version of a gene where two copies are needed for it to be expressed

Question 10

homozygous

Answer 10

two of the same alleles

Question 11

heterozygous

Answer 11

two different alleles 

Question 12

homologous pair

Answer 12

pair of chromosomes, carry genes controlling the same features at the same positions on each chromosome. the member of each homologous pair have the same size and shape

Question 13

diploid cells

Answer 13

46 chromosomes-23 homologous pairs like human cells

Question 14

haploid cells

Answer 14

A cell that contains a single set of chromosomes

Question 15

when does mitosis occur

Answer 15

need to divide for growth, repair, cloning and asexual reproduction

Question 16

what is mitosis

Answer 16

when a parent cell divides into two daughter cells that are genetically identical and have the same number and type of chromosomes. This happens in all human cells except gamets

Question 17

what must the dividing cells do to achieve mitosis

Answer 17

• must copy each chromosome before it divides this involves DNA replicating
  -must divide in a way that each daughter cell receives one copy of every chromosome

Question 18

what is mono hybrid inheritance

Answer 18

the inheritance one one allele can be found with a punnet square

Question 19

what do family pedigrees show

Answer 19

the inheritance of an allele over generations

Question 20

what is meiosis

Answer 20

the formation of 4 non identical cells from one cell to form gamets (haploid cells)

Question 21

what 2 things must parent cell do in meiosis

Answer 21

• copy each chromosome so there is enough genetic material for the 4 daughter cells
  -must divide twice in a way that each daughter cell receives one chromosome from each pair

Question 22

events of meiosis cell division

Answer 22

1st division- one chromosome from each homologous pair goes into each daughter cell 
2nd division- chromosome separate into 2 chromatids and goes to each daughhter cell

Question 23

two differences between mitosis and meiosis

Answer 23

-mitosis produced 2 genetically identical cells whereas meiosis produces 4
-mitosis produces diploid cells whereas meiosis produced haploid cells

Question 24

sexual reporting

Answer 24

the fusion of two gamets to forms genetically different zygote

Question 25

asexual reproduction

Answer 25

involves a single parent, creating genetically identical offspring used for cloning and happens commonly in plants

Question 26

genetic variation

Answer 26

the difference in DNA sequences of individuals in the same species

Question 27

mutation

Answer 27

rare and random changes in genetic material that can be inherited 

Question 28

evolution definition

Answer 28

change in form of an organism over the course of time

Question 29

natural selection definition

Answer 29

process where certain individuals in a population survive because they have better adapted to their environment

Question 30

how natural selection works

Answer 30

1. variation within a species, brought be mutation 2. changing conditions in an environment (selective pressure), favors one form of species (selective advantage) 3. frequency of favored form increases, survival of the fittest 4.passes on allele by reproduction, selective advantage becomes widespread.

Question 31

what is antibiotic resistant

Answer 31

-antibiotic kill bacteria, most common=penicillin we have been using them for so long that come bacteria had become resistant. -this happens when a mutation is developed in the DNA -the resistant bacteria survives and cant be killed, no longer effective

Question 32

what is speciation

Answer 32

- a population gets geographically separated because of the environment -this prevent interbreeding -different mutations take place in isolated groups and create different phenotype -they evolve and can now not interbreed

Question 33

what is selective breeding

Answer 33

-breeding only the individuals with the desired characteristics -called artificial selection, humans make choice not environment -offspring have higher chance of inheriting desired characteristics

Question 34

reasons why animals are selectively bred

Answer 34

-greater quantity of offspring -better quality skin/fur -more disease resistant -run raster

Question 35

reasons why plants are selectively bred

Answer 35

-high yield -pest resistant -drought/ flood resistant -more nutritious/ better flavour -longer shelf life