biology year 9 eoy- aqa

chapter 1- cell biology and transportation, chapter 3- organisation and the digestive system, chapter 4 (part) - blood and heatr

what are two types of eukaryotic cell

animals and plants

what types of cells are bacteria

prokaryoticv

where is DNA found in eukaryotic cells

in the nucleus

what is the function of the cell membrane

to control the movement of substances in and out of the cell

what is the function of the mitrondira

site of aerobic respiration to transfer energy for the cell

what is the funciton of the chloroplasts

contain chlorophyll to absorb light energy for photosynthesis

what is the function of ribosomes

to enable production of proteins (protein synthesis)

what is the funciton of cell walls

to keep support and strengthen cell keeping it rigid

what structure of the main genetic material in the prokaryotic cell

a single loop of dna

how are elctron microspoces different to light microscopes

electron microscopes use beams of electrons instead of light, tehy cannot be used to view living samples, much more expensive, high magnifcation and hihger resolution

what is the function of the red blood cells

carries oxgyen around the body

give three adaptions of a red blood cell

no nucleus, a red pigment called haemoglobin, has a bi-concave disc shape

what is the function of the nevre cell

carry electrical impluses around the body

what are two adaptions of the nerve cell

brached ending, myelin sheath insluates the axon

what is the function of the sperm cell

to fertilise an ovum (egg)

give two adpations of the sperm cell

tail, contain lots of mitochondria

what is the function of a palisade cell

carries out photosynthesis in a leaf

give two adaptions of a palsiade cell

alots of chloroplasts locatied at hte top surface of the leaf

what is the function of a root hair cell

to absorb minerals and water from the soil

what are two adaptions of the root hair cell

long projection and lots of mitochondria

what is diffusion

the net movement of particles from an area of high concentration to an area of low connections along a concentration gradient

name three facotrs that affect the rate of diffusion

concentration gradient, temperature, membrane surface area

how are the villi adapted for exchanging substances

• long and thin- increases surface area

• one-cell-thick membranes- short diffusion pathway

• good blood supply- maintain a steep concentration gradient

how are the lungs adapted for efficent gas excahgne

• alveoli- large surface area

• moist membranes- increase rate of diffusion

• one-cell-thick membranes- short diffusion pathway

• good blood supply- maintains a steep concentration gradient

what is osmosis

Osmosis is the movement of water molecules across a partially permeable membrane, from a region of high water concentration to low.

give an example of osmosis in a plant

water moves from the soil into the root hair cell

what is active transport

the movement of particles against a concentration gradient- from a dilute solution to a more concentrated solution- using energy from respiration

why is active transport needed in plants roots

concentration of mineral ions in the soil is lower than inside the root hair cells- the mineral ions must move against the concentration gradient to enter the root hair cells

what is the purpose of active transport in the small intesnite

sugars can be absorbed when the concentration of sugar in the small intestine is lower than the concentration of the sugar in the blood

name the five levels of organisation

cells —> tissues —> organs —> organ system —> organisms

what is a tissue

a group of cells with similar structure and functions

what is an organ

a group of tissues working together to perform a specific function

what is the function of the liver in digestion

produces bile, which neutralises hydrochloric acid in the stomach and emulsifies fat to form small droplets with large surface areas

what is the function of saliva in digestion

lubrication to help swallowing- contains amylase to break down starch

name three enzymes produced in the pancreas

lipase, amylase, protease

what are enzymes

protein molecules that catalyse specific reactions in organisms

why are enzymes described as specific

each enzyme only catalyse a specific reaction because the active site only fit together with certain substrates (like a lock and key)

describe the function of amylase

to break down starch into glucose

where is amylase produced

small intestine, salivary glands, pancreas

describe the function of protease

to break down proteins into amino acids

where are proteases produced

small intestine, pancreas, stomach

desrcibe the function of lipases

break down lipids into fatty acids and glycerol

where are lipase produced

pancreas, small intestine

what are two factors that effect the rate of activity on an enzyme

temperature and pH

what does denuatured mean

the shape of an enzymes active site is changed by high temperature or extreme pH so it can no longer bind with the substrate

describe the effect pf temperature on enzyme activity

as temperature increases, rate of reaction increase until it reaches the optimum for enzyme activity- above this temperature enzyme decreases and then stops

describe the effect of pH on the enzyme activity

different enzymes have a different optimum pH at which their activity is greatest- a pH much lower or higher than this enzyme activity decreases and stops

why do different digestive enzymes have different optimum pH

different parts of the digestive system have very different pHs- the stomach is strongly acidic and the pH in the small intestine is close to neutral

what is an organ system

a group of organs working together to perform a specific function

name the four main components of blood

plasma, white blood cells, red blood cells, platelets

what is the function of the platelets

form blood clots- prevent loss of blood and stop wound becoming infected

why is the human circulatory system a double circulatory system

blood passes through the heart twice for every circuit around the body- deoxygenated blood is pumped from the right side of the heart to the lungs and the oxygenated blood that returns is pumped from the left side

how does the structure of the artery relate to its function

carries blood away from the heart under high pressure- has a small lumen and thick, elasticated walls so it can stretch

how does the structure of a vein relate to its function

carries blood back to the heart at low pressure- doesn’t need thick elasticated walls but has valves to prevent blood flowing the wrong way

how does the structure of a vein relate to its function

carried blood to heart at a low pressure- does not need thick elasticated walls, but has valves to prevent blood flowing the wrong way

how does the structure of capillary relate to its function

carries blood back to cells and tissues- has a one-cell thick wall to provide a short diffusion distance

list the structures air passes through when breathing

mouth/nose —> trachea —> bronchi —→ bronchioles —→ alveoli

what is the function of red blood cells

bind oxygen and transport it around the body

what is the function of the white blood cells

defend the body against pathogens

what is the function of the plasma

transport dissolved substances such as urea, hormones and digested food products around the body

why is a leaf an organ

there are many tissues inside the leaf which work together to perform photosynthesis