Biology HT1
an animal cell contains
cell membrane
nucleus
mitochondria
cytoplasm
in addition to the sub-cellular structures found in animal cells, plant cells contain
chloroplasts
cell wall
vacuole
what does a vacuole do
it is a fluid filled sack that stores water
factors affecting diffusion
membrane surface area
temperature
concentration gradient
in osmosis
water moves where there is less of it
the concentration becomes the same at both ends
in active transport, molecules are transported from a
low concentration to a high concentration
active transport takes place in
guts of humans
roots of plants
which of diffusion, osmosis and active transport are examples of passive transport
diffusion and osmosis
enzymes have an optimum pH (measure of acidity); if the pH changes away from the optimum pH, then the
enzyme activity decreases
if the pH is too low or too high, then the enzyme is
denatured and will not function
proteins (e.g. enzymes) are built from chains of lots of
amino acids joined together
why is the shape of an enzyme's active site important
to carry out a specific function
when investigating the rate of enzyme activity, what factors need to be kept constant
pH
temperature
enzyme concentration
substrate concentration
amylase breaks down what
starch into sugars
where is amylase produced
it is produced in the salivary glands and the small intestine
where is pepsin produced
pepsin is produced in the stomach
why is the pH in the stomach lower than saliva
the pH of the stomach is a lot lower than the pH of saliva, due to the presence of stomach acid
pepsin is produced in the stomach, which means
this means pepsin likely has a lower (more acidic) optimum pH than amylase
how are alveoli adapted for their function
they have a large moist surface area
they have a rich oxygen supply
they are very close to capillaries, so the distance for gases to diffuse is small
where do you find glucose and why do we eat it
simple sugars and for a fast release of energy
where do you find starch and why do we eat it
complex sugars and for a slow release of energy
where do you find amino acids and why do we eat it
proteins and for growth and repair
where do you find fat/lipids and why do we eat it
fatty acids and for insulation and protection
what do use to find glucose in foods
benedict's solution
what do use to find starch in foods
iodine solution
what do use to find protein in foods
buiret's solution
what do use to find fats in foods
sudan 3
what happens if you add benedict's solution to glucose
blue to yellow/orangey red
what happens if you add iodine solution to starch
it turns to blue/black
what happens if you add buiret's solution to protein
blue to lilac/purple
what happens if you add sudan 3 to fats
cloudy/milky to red layer on top
what special condition do you need when you add benedict's to glucose
it needs to be in boiling water (80 degrees) for 2 mins
what is the same in plant and animal cells
a nucleus, cell membrane, cytoplasm and mitochondria
what does a plant cell have that an animal cell doesn't
a cell wall, chloroplasts and a large central vacuole
the digestive system contains (in order)
mouth (salivary lands)
oesophagus
stomach
small intestine
large intestine
rectum
anus
other organs that produce chemicals neccessary for digestion
liver (makes bile)
gallblader (stores bile until needed)
pancreas (makes and releases enzymes)
the pancreas stomach and mouth contain what used for what
glands which produce specific enzymes for which type of food we eat (carbs/protein/fats)
how is the small intestine designed to absorb nutrients efficiently
it's longer
it contains villi which absorbs nutrients
it had a good blood supply
it has thin walls (diifusion rates)
what are the three digestive enzyme types and an example
protease (pepsin)
carbohydrase (amylase)
lipase (lipase)
what does protein (pepsin) digest and what is made
protein and amino acids
what does carbohydrase (amylase) digest and what is made
starch and glucose
what does lipase (lipase) digest and what is made
lipids/fats and glycerol/ fatty acids
what theory applies to enzymes
lock and key
what 2 factors effect enzyme activity the most
temp and pH because if they aren't right they denature
describe the pH scale
it goes from 0 to 14 7 being neutral anything less than 7 is an acid and anything above is an alkali
what is emulsifiction
when a bigger droplet (fat) shrink into smaller pieces so (lipase) can absorb them
what does bile do
it emulsifies lipids/fats
it neutralises stomach acid
what does hydrochlorc acid do
has a low pH fo pepsin and stomach enzymes
kills some bacteria
what makes up blood
wbc
rbc
plasma
platelets
what is the function of the blood
to carry around oxygen and nutrients around the body
a rbc does what
carries oxygen to the lungs than around the body
a wbc does what
destroys invading microbes
plasma does what
transports dissolved nutrient molecules CO2 and urea
platelets do what
clots the blood e.g scabs
what does a rbc contain
haemoglobin
biconcave structure
cell membrane
cytoplasm
arteries go where
away from the heart
veins go where
into the heart
capillaries do what
link the veins and arteries
what are some adaptations of arteries
thick walls containing muscle and has a narrow lumen
because the blood is under pressure
what are some adaptations of veins
thin walls and a wider lumen they act like valves
to prevent backflow of blood
what are some adaptations of capillaries
they have thin walls and are narrow
which allows substances like glocose and oxygen to pass through
blood enters the heart through
the vena cava
after the vena cava the blood goes through
the right atrium and the right ventricle
after the right ventricle it goes up into the
pulmonary artery
after the pulmonary artery it goes through the
pulmonary vein
after the pulmonary vein (left) it goes through
the left atrium and the left ventricle
and finally after the left atrium then the left ventricle it goes through
the aorta
why is the left ventricle thicker
to push blood further
what is in the lungs system
trachea
ribs
lung sack
diaphragm
alveoli
bronchiolus
bronchide
at the top of the plant cell there is a
waxy cuticle and a upper epidermis
in the middle of the leaf there are
palisade cells and the spongy mesophyll
at the bottom of the leaf there are
the lower epidermis and the guard and stomata cells
what do both the xylem and phloem do
carry substances
part of vascular bundles
what is a xylem
it's a hollow dead tube that does transpiration (water) travels up
what is a phloem
it's a living cell tube that does translocation (glucose) it also has pores and travels up and down
what affects transpiration
light intensity (photosynthesis)
temp (evaporation)
wind (water vapour removed evaporation)
humidity (water vapour) decrease