semester 2: biology exam revision

gene

an inherited characteristic made of DNA

• controls structures and function

allele

variation of a gene

human genome

total set of genetic DNA in a somatic cell

epigenetics

study of mutations to gene expression

• how env. impact

• no DNA change

somatic cell

• full set, 46 chromosomes

• diploid

gametes

• sex cells, 23

• haploid

• sperm and ova

autosomes

chromosomes 1-22

• 22 pairs or 44 overall

• controls autosomal abnormalities

• determines all non-sexual physical characteristics

sex chromosomes

pair 23

• sexual characteristics

karyotype

• assigned sex

• no. of chromosomes

• abnormalities

meiosis

produces gametes (haploid, 23) with ½ the genetic material of the original cell

variation

• meiosis produces random combinations of homologous pairs via independent assortment in metaphase 1

• meiosis also exchange chromatids segments between chromosomes called crossing over in prophase 1

metaphase 1

homologous chromosomes line up in the centre and spindle fibres attach

• 1 cell

metaphase 2

pairs of chromatids line up along equator of cell and spindle fibres form and attach to centromere

• 2 cells

co-dominace

when both dominant alleles are expressed in the phenotype

blood types

• IA- A

• IB- B

• i -O

• IA and IB - AB

asexual reproduction

where one parent organism produces offspring genetically identical to it

• no sex cells - fast and efficient

• bad: disease may affect all individuals in a population + may only be adapted to one env and cant change

clone

getting DNA from one living organism and creating identical copies of it

• adult cloning from fully developed adult tissue - diploid

• issues: expensive age faster

• good: save endangered species

budding -eukaryote

bud breaks off from main organism and carried to new location to settle and develop

• less competition

• e.g. sea sponge

fragmentation - eukaryote

parent organism is divided into separate parts and can regenerate into identical organism

• e.g. sea star

• fast, less energy and no partner

asexual in plants

vegetative propagation

• cutting of roots or stems to give rise to identical plants

• bigger produce, colouration and endangered

sexual reproduction

fusion of 2 haploid gametes to form a genetically unique zygote

• inc. genetic diversity which allows org. to adapt and change to the environment

• more energy and time spent to build population and courtship

genotype

set of genes in DNA for a particular trait

phenotype

visible trait

SCNT

• full set of chromosomes from organism

• remove nucleus from egg cell because only donor DNA is needed for egg nucleus

• fuse with electricity to start cell division or nothing will happen when implanted in surrogate

• implant in surrogate —> develop clone and give birth

structural adaptations

physical features

• size

• fur

• colour

behavioural adaptations

how they act

• hibernation

• migration

physiological

cellular/internal changes

• camouflage

• venom

mutualism

where organisms benefit and neither is harmed

commensalism

where 1 benefits and the other is unaffected

ammensalism

where one is inhibited or destroyed while the other remains unaffected

parasitism

where one is affected (host) and the other benefits (parasite)

keystone species

have a disproportionately large effect on other organisms in an ecosystem and important in maintaining balance

• once it is removed it cannot be replaced

benefits of keystone species

• maintains a population of animal

• food chain works effectively

• allow some animals to grow in food chain

negatives when keystone species removed

• stops food chain

• pop decrease for certain animal

• competition with fewer resources

competition

members of the same or different species compete for resources necessary for survival

• abiotic: non-living - space, oxygen levels

• biotic: living - predators, diseases

• intra: same

• inter: diff

predator-prey

where predator kills prey but number of each is dependent on the other

• prey decline, predator decline - less food

• predator decline, prey increase - not hunted

Aboriginal and Torres Strait Knowlege

community practices ensure that the density and distribution of populations aren’t negatively impacted

• only take food they need to prevent over hunting and population recover

autosomal dominant

on the autosomes 1-22

• males and females equally affected

• all affected have at least 1 affected parent

autosomal recessive

expressed when 2 copies of recessive allele are present

• males and females equally affected

• 2 unaffected can have an affected child

x-linked dominant

dominant gene carried on x chromosome and only 1 copy is needed to express phenotype

• more affected females than males

• male with trait passes onto all daughters but no sons

x-linked recessive

trait on the x chromosome where 1 copy is required in males to express phenotype or 2 copies in females

• more males than females show the trait

• all sons of females with the trait are affected

linked genes

genes close together on a chromosome

• if 2 gene loci are linked, the test cross will show 4 classes of offspring that are not equal proportions

• if not linked, the test cross will have 4 classes of offspring in relatively equal proportions

Consequence-based approach

considers the consequence of the actions

• choosing a solution with maximum positive outcomes and minimum negative effects

Duty-based approach

people who have a duty and act in a particular way

• do things by law

Virtues-based approach

approach is person-based, rather than action-based

• consideration of ‘moral character’

Ethical concept 1 - Integrity

being honest when sharing all information sources and findings (positives and negatives)

Ethical concept 2: Justice

making sure different options are treated fairly and with equity

• will everyone have access to it?

• will everyone be able to afford it?

Ethical concept 3: Beneficence

maximising benefits and minimising risks and harm from an action

• who benefits?

• how will it benefit?

Ethical concept 4: Non-maleficence

Try causing no harm

• if there is harm, benefits should be maximised

Ethical concept 5: Respect

respect of the welfare, liberty, autonomy, beliefs, perceptions, customs, and cultural heritage of an individual.

homologous

• same gene loci but does not mean same allele

• the same