paper 1 Flashcards
describe diffusion
the net movement of particles from an area of high concentration to an area of low concentration
define osmosis
the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to lower water concentration
how to work out change in mass
final mass - initial mass/ initial mass
what happens in prophase
chromosomes condense and the membrane breaks down
what happens in telophase
membranes form around each new set of chromosomes, forming the nuclei of two new cells
what does mitosis produce
two diploid daughter cells that are genetically identical
what happens in interphase
DNA duplicates so each set of chromosomes are identical
what happens in ana phase
spindle fibres pull each chromosome to either side
what happens during cytokinesis
cytoplasm and cell nucleus membrane divides
how do plants grow
cell division and elongation
how do animals grow
they grow while they r young but stop and DIFFERENTIATE throughout their lives
how are tumours formed
uncontrollable cell division by a CHANGE IN GENE which produces an abnormal mass of cells
at what point is a tumour classed as cancerous
when it invades/damages the surrounding tissue
what’s the function of the cerebrum
movement, intelligence, memory, language, vision
what’s the structure of the cerebrum
split into two hemispheres (left and right)
what’s the function of the medulla oblongata
unconscious activities (HR and breathing)
what’s the function of the cerebellum
controls muscle coordination and balance
what’s the difference between PET and CT
CT shows structure in a picture, PET shows structure and activity and function irl
easiest way to remember mitosis
duplicate, breaks down, lines up, apart, membrane, divides
what’s the order of mitosis
(interphase), prophase, metaphase, anaphase, telophase, cytokenisis
what is reaction time
time taken to respond to a stimulus
what does the body have lots of and what do they do
sensory receptors, detect a change in environment
what’s the order of a stimulus response
stimulus, receptors, sensory neurones, cns, motor neurone, effector, response
in the response to a stimulus what goes first motor neurone or sensory neurone
sensory neurone THEN motor neurone
where does cell elongation take place in plants
roots and shoots (meristems)
what does the cornea in the eye do
refracts light into the eye
what does the iris do
controls how much light enters the pupil
what does the lens do
refracts light to focus on the retina
what does the retina do
it’s light sensitive and detects light (covered in rods and cones)
what type of light are rods sensitive to
dim lights
what are cones more sensitive to
different colours
what is colourblindness caused by
cones in the retina not working properly
what can long sighted not do
focus on CLOSE objects
what can short eyed people not do
focus on FAR objects
what is different in the eye when someone is long sighted
light is focused behind the retina because it doesn’t bend light enough and the eyeball is to short
what is different in the structure of the eye when someone is short sighted
light focuses infront of the retina because it bends the light too much and the eyeball is too long
what lenses are used for long sighted people
CONVEX
what lenses are used for people with short sighted vision
CONCAVE lens
what detects VERY bright light
light receptors
what happens to the iris when light is bright
muscles contract and iris goes smaller
what is a choromosome
long coiled up molecules of dna found in the nucleus
what is a gene
a section of dna on a chromosome that codes for a particular protein
what is a genome
all the dna/genetic material of an organism
what is mutation
a random change to an organisms dna base sequence that can be inherited (genetic variant)
what is an allele
different versions of a gene (two versions of every gene)
what is homozygous
two alleles for a particular gene that are the SAME
what is heterozygous
two alleles for a particular gene that are DIFFERENT
what do dominant alleles do
overrule the recessive alleles (becomes present in the offspring)
how would a gene express a recessive characteristics
if both alleles are recessive
what is a genotype
is a combination of alleles you have
what is a phenotype
the characteristics you have
what is a gamete
the male or female reproductive cell that contains half the genetic material of an organism (join together)
what is a zygote
fertilised egg that is a result from a female gamete and male gamete
what’s the role of neuro transmitters
transfer nerve signals by chemicals which diffuse across the synapse
what do synapses connect
two neurones (eg sensory and motor)
structure of a sensory neurone
one long dendron, one short axon
what’s the structure of a motor neurone
many short dendrites, one long axon, myelin sheath
relay neurone structure
many short dendrites and an axon
how is a bacteria cell different (prokaryote)
no nucleus, ribosomes and flagellum
