BIOLOGY PAPER 2 GCSE AQA COMBINED HIGHER

genome

an entire genetic code

gene

a portion of DNA that codes for protien

genotype

a specific genetic code

phenotype

how genetic code is shown physically

Homeostasis

an organisms ability to maintain regular internal conditions so crucial reactions can take place in optimum rates

what in the body needs to be regulated?

blood glucose concentration

where are the central nervous systems?

the brain and spinal cord

what is the purpose of the pituitary gland?

it is the master gland that sends signals to other glands.

what is the purpose of the pancreas?

secretes insulin and glucagon to control blood sugar

what is the purpose of the testes?

to produce sperm

what is the purpose of the ovaries?

releases eggs and secretes hormones

what is the purpose of the adrenal glands?

releases adrenaline (causing the fight or flight)

what is the purpose of the thyroid?

controls growth, metabolism and more

how does the body control high blood glucose levels?

-pancreas secretes insulin

-causes glucose to move from bloodstream into cells for respiration

-excess glucose is stored as glycogen as an energy store

how does the body control low blood glucose levels?

-pancreas secretes glucagon

-causes liver and muscles to convert glycogen back into glucose

type 1 diabetes

when the pancreas cant produce insulin so injections are needed (usually genetic)

type 2 diabetes

cells donnt absorb the glucose normally (usually caused by lifestyle ie obesity etc)

what is FSH (follicle stimulating hormome)

from the pituitary gland and causes eggs to mature

what is oestrogen?

causes uterus lining to thicken and inhibits FSH so no more eggs mature until the next cylce. also causes pituitary gland to secrete.

what is LH (luteinising hormone)?

causes egg to be released towards uterus so sperm can fertilise it while in the oviduct

What is progesterone?

secreted by ovaries and maintains uterus lining

forms of contraception

FSH-inhibiting pills (so no eggs can mature.)

progesterone implant (to stop eggs being released.)

condom (used as a physical barrier.)

IUD (stops egg embedding in lining.)

avoiding intercourse.

invitro fertilization

eggs collected after inducing release with LH to be fertilised in a lab then inserted back into uterus.

(hard, expensive, low success rate)

Meiosis

Cell division that produces gametes (genetically different from parent cells but produces identical cells)

sexual reproduction

A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents (most animals)

asexual reproduction

happens by mitosis meaning the daughter cells are identical

heterozygous and homozygous

**hetero - different

**homo - same

punnet square

diagram that can be used to predict the genotype and phenotype combinations of a genetic cross

Darwin's Theory of Evolution

Those individuals that are best adapted to the environment will survive and reproduce; those traits that help them, become more common in a species and maladaptive traits die out. This is called natural Selection.

Lamarck's Theory of Evolution

the idea that acquired traits, like a stretched neck in a giraffe from eating from trees, is passed on to offspring

selective breeding

the process of selecting organisms with desired traits to be parents of the next generation

species

A group of similar organisms that can breed and produce fertile offspring.

genetic engineering

Process of making changes in the DNA code of living organisms

fossils

decayed remains of organims or evidence of their existence.

fossils look like bones that have been replaced with minerals.

classification and linnaeus's taxamony

kingdom (king)

phylum (phillip)

class (came)

order (over)

family (for)

genus (good)

species (soup)

binomial name = genus+species

domain

a level above kindom which consists of;

archaea (primitive bacteria) , bacteria (true bacteria) and eukaryota (everything else - DNA contained in nucleus)

what do organisms compete for?

food, water, shelter, mates, Co2, light

what do food chains consist of?

producer (plants/algae) , primary consumer (herbivore/omnivore), secondary consumer (carnivore/omnivore) , tertiary consumer (carnivore/omnivore)

carbon and water cycles

carbon is recycled when an organism dies and decomposes as they excrete Co2 while alive

biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

peat bogs

wetlands in which dead organic matter accumulates

Biomass

the total mass of organisms in a given area or volume.

food security

Physical, social, and economic access at all times to safe and nutritious food sufficient to meet dietary needs and food preferences for an active and healthy life.

sustainable fishing

Fishing up to the maximum sustainable yield so that future fish stocks are not at risk of being depleted