Download What is active transport? Moves materials against a conc. gradient

What is active transport?
What are features of cells that carry out lots
of active transport?
What are examples of situations where active
transport is used?
What is the function of the alveoli? What are
the adaptations?
What products are absorbed in the small
intestine?
How is the gut adapted for effective
absorption?
Moves materials against a conc. gradient;
requires energy; carried out by proteins in the
cell membrane
Many mitochondria
Marine birds & mammals have salt glands to
pump out salt into the sea; uptake of mineral
ions in the roots; transport of glucose out of
the gut & kidney tubules into the blood.
Point of gas exchange in the lungs; increase
surface area in lungs; good blood supply
maintains conc. gradient; thin walls for easy
diffusion; moist surface for easy diffusion
Glucose (from carbohydrates); amino acids
(from proteins); fatty acids & glycerol (from
lipids)
Large surface area (villi, microvilli); rich
blood supply (maintains conc. gradient);
moist surfaces for substances to dissolve;
short diffusion pathway
Guard cells open & close the stomata to
control carbon dioxide going into & out of
the leaf; water evaporates through stomata
(again controlled by guard cells); guard cells
are controlled by water moving in & out of
them by osmosis
How do gases move into & out of a leaf?
What factors affect the rate of transpiration?
Temperature (particles have more energy:
more diffusion); wind (maintains a conc.
gradient); humidity (lowers the conc.
gradient)
Use a potometer; as water evaporates from
the leaves, it is pulled along tubes; a
measurement of water can be made using the
scale; this shows the volume of water lost.
How can we
transpiration?
measure
the
rate
of
What are the features of an artery?
What are the features of a vein?
What are the features of a capillary?
What is in the blood?
Why does your heart rate increase when you
exercise?
What other changes take place when you
Carries blood away from the heart; thick
walls; small lumen; thick layer of muscle +
elastic fibre
Carries blood back to the heart; thin walls;
small lumen; valves
Carries blood to the respiring cells; walls a
single cell thick; tiny vessel; narrow lumen
Plasma (carries urea, glucose, amino acids,
ions & CO2); red cells (carry O2); white cells;
platelets; large proteins.
Muscles contract more; need more energy;
from respiration; heart pumps more blood,
carrying more O2; taking away more CO2 &
lactate.
Breathe more deeply & more quickly;
exercise?
What is anaerobic respiration?
What is oxygen debt?
What is the role of the kidney?
What is dialysis?
Advantages & disadvantages of a kidney
transplant
How could we grow microbes safely in the
lab?
How do yeast help make bread?
How do yeast help make alcohol?
How do we use bacteria to make yoghurt?
muscles use up stores of glycogen;
vasodilation allows blood to flow to skin
surface (cools)
Glucose  lactic acid (+ energy); less energy
than aerobic respiration; can’t do this for
more than a few se
Anaerobic respiration produces lactic acid;
this needs to be broken down using oxygen;
O2 debt = amount of O2 needed to break down
lactic acid
Filter waste from the blood; reabsorbs all of
the sugar (active transport); reabsorbs as
much water as the body needs; reabsorbs
some ions
Used by people with kidney failure; blood
leaves body & flows between partially
permeable membranes; on the other side of
the membranes is dialysis fluid; the conc.
gradient makes unwanted substances diffuse
out of the blood; these include urea & excess
mineral ions.
Advantages: eat what you want; do not need
time consuming dialysis; live a normal life.
Disadvantages: Need a donor (rare); rejection
risk; needs to take drugs every day
All equipment is sterile to prevent
contamination; agar plates are carefully
inoculated with microbes; plates are
incubated at room temperature (low) to
reduce growth of pathogens; after use, all
equipment is heated to kill microbes &
thrown away.
Yeast mixed with sugar to give it an energy
source for respiration; yeast + sugar mixed
with water + flour & left somewhere warm;
as yeast cells respire aerobically they produce
CO2 making the bread rise; yeast cells are
killed during the cooking process
Large no. of yeast in the absence of oxygen;
yeast respire anaerobically (fermentation);
they break down sugar to produce ethanol
+ bacteria to warm milk; keep mixture warm
so bacteria grow; bacteria break down lactose
(sugar) in milk for respiration; producing
lactic acid; this makes milk solidify into
yoghurt
Good O2 supply for respiration; stirrer (keeps
microbes in suspension – less crowding);
water cooled jacket (removes excess heat
from respiration; pH probe & temperature
probe
How do we get the maximum yield from a
fermenter?
Lag: growth is slow initially as there a few
microbes to ÷. Log: growth is exponential
(fastest growth rate). Stationary: growth
slows as factors become limiting. Death:
microbes die as conditions become
unfavourable
What is happeneing in the growth curve?
How can yeast produce fuel for your car?
Advantages & disadvantages of ethanol as
fuel?
What is a biogas generator?
Advantages of burying a biogas generator
underground?
Ethanol based fuels can be produced from:
anaerobic fermentation of cane sugar; glucose
derived from maize starch using carbohydrase
Advantages: carbon neutral; fewer emissions.
Disadvantages: lots of plant material required
initially; should we grow food crops instead?
Faeces
&
urine
from
agriculture;
anaerobically fermented; produces methane
Less temperature fluctuation; less visual
impact; withstand pressure build up; ease of
adding slurry