p1 predictions

3 ways to prevent mosquito bites

• wear long(er) sleeves / clothes

allow reduce bare skin exposure

• use insect repellent or insecticide

• mosquito nets

why does the plant cell contains mitochondria but the bacterial cell does not contain mitochondria.

bacterial cell is too small

stages of the cell cycle

stage 1: DNA / chromosomes replicate and sub-cellular structures increase in number

stage 2: one set of chromosomes is pulled to each end of the cell

stage 3: cytoplasm and cell membrane divide to form 2 identical daughter cells

does a RBC have nucleus

no

what shape is a plant cell

rectangular

Explain why the red blood cell bursts but the plant cell does not burst.

 water enters (the cells) by osmosis

plant cell has a cell wall (which prevents it from bursting)

function of haemoglobin

carries oxygen

from lungs to tissues

what to always say when talking about respiration

if its aerobic or anaerobic

why do many of the cells in a plant root store starch.

starch is energy source / store (for active transport)

how to convert 1 mm into micrometre

multiply by 1000

Give two advantages of using an electron microscope instead of a light microscope.

high(er) magnification

high(er) resolution

Give two ways onion cells would look different when seen using an electron microscope.

(would) look more magnified / bigger

(cell would) have more detail

or

(would) be at a higher resolution

or

(could) see more sub-cellular structures

or

sub-cellular structures seen in detail

3 reasons why a womens 3 children r not genetically identicak

•   different egg / sperm each time

•   genes from two parents

•   each gamete / egg / sperm has different alleles / genes / DNA / genetic information

Which two factors can cause cancer?

antibiotics and viruses

Give two advantages of using an electron microscope instead of a light microscope.

high(er) magnification

high(er) resolution

What is the function of mitochondria?

to transfer energy for use

by (aerobic) respiration

Describe the function of muscle cells in the wall of the stomach.

contract

to churn / move / mix food

why does anaerobic respiration release less energy than aerobic

less energy released / transferred (per molecule of glucose)

(due to) incomplete breakdown / oxidation of glucose

why is having more rbcs good for an athete

there is) more haemoglobin so more oxygen (carried / bound

(athlete can do) more aerobic respiration to transfer / release (more) energy

Explain the advantages of red blood cells passing through a capillary one at a time.

more oxygen released (to tissues)

•        slows flow

•        shorter distance (for exchange)

•        more surface area exposed

conversion of mm to nm

x 100 000 000!!!!!!!

4 aspectic techniques for investigating effectiveness of antibiotics

•   sterilise equipment / surfaces (before use)

•   (use) sterilised agar

•   secure lid of the Petri dish with (adhesive) tape

•   only lift lid of Petri dish a little (when setting up plate)

Name 2 medical conditions that could be treated using heart cells created from an embryo.

CHD and cardiovascular disease

1 good thing about using stem cells for donar organs

can be done immediately and no need to wait

why is using a stent in a trachea good

stent opens up the trachea

allowing air to flow through

Evaluate the use of stem cells from a patient’s own bone marrow instead of stem cells from an embryo.

what type of cell division causes the change in number of E. coli cells

binary fission

what will happen if bacteria have no nutrients

die

Describe how water moves from roots to the leaves.

by transpiration stream / pull

in xylem

why is it good to have most stomata on lower side of leaf

less water lost

so it does not wilt

Describe, as fully as you can, how urine is produced by the kidneys.

  • filtration of blood

•        reabsorption / substances taken back into blood

•        (reabsorption) of all of the sugar / glucose

•        (reabsorption) of some of ions / of ions as needed by body

•        (reabsorption) of some of water / of water as needed by the body

•        urea present in urine / urea not reabsorbed

•        reabsorption of water by osmosis / diffusion

or reabsorption of sugar / ions by active transport

what does activ transport happen across

membrane

formula for respiration in plants

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Describe the process of active transport in the root hair cells of plants.

take up of (soluble) substances / ions against the concentration gradient

through the (semi-permeable) (cell) membrane

energy from mitochondria

Explain why putting pressure on the heart helps the person.

pushes / moves blood

to get oxygen around the body

Describe how forcing air into the person’s lungs helps the person.

 provides oxygen (for respiration)

Explain the effect of a partly blocked coronary artery on the human body.

reduced blood flow to heart (muscle / tissue / cells)

•   (so) less oxygen to heart (muscle / tissue / cells)

•   (so) less (aerobic) respiration (in heart / body cells)

 (more) anaerobic respiration

•   (so) less energy (released)

•   (so) less blood / oxygen / glucose around the body (from heart)

 less carbon dioxide removed from body (muscle / tissue / cells)

•   (resulting in) breathlessness

•   (resulting in) tiredness

 (anaerobic respiration causes) production of lactic acid

•   (build-up of lactic acid) causes muscle fatigue / pain or chest pain

Other than heart disease, name two conditions which are linked to obesity.

•        arthritis

•        diabetes

•        high blood pressure

•        strokes

Give the three main stages in testing a new drug before it is sold to the public.

laboratory tests / tests on tissues

tests for side effects on volunteers / healthy people / small numbers

test on patients / sick people

Describe what happens during blood clotting.

involvement of platelets / eg platelets ‘trigger’ clotting process

meshwork formed (which traps blood cells)

Describe how the structure of an artery is different from the structure of a vein.

 doesn’t have valves

has a thicker wall or thicker layer of muscle doesn’t have valves

Give 4 differences in the composition of the blood in an artery and vein

•        (artery has) more oxygen

•        (artery has) more glucose

•        (artery has) less carbon dioxide

•        (artery has) less lactic acid

Suggest 4 possible advantages of using the new artificial blood, instead of using human blood for a transfusion in humans.

•        no rejection

•        abundant supply

•        low risk of infection

•        longer shelf life

what can happen w a leaking heart valves

backflow can occur or some blood flows backwards

what do u have to take alongside mechanical heart valves

statins/blood thinners

do mechanical or biological valves last longer

mechanical

role of white blood cells

defence against or destroy pathogens / bacteria / viruses / microorganisms

what factors must be checked on an artificial heart valve before insertion

•        that it doesn’t cause an immune response or isn’t rejected / damaged by white blood cells

•        whether it is a long lasting material / doesn’t decompose / corrode / inert

•        if it is strong (to withstand pressure)

•        it will open at the right pressure

•        that it doesn’t cause clotting

•        that it doesn’t leak or it prevents backflow

•        non toxic

what is a drug

 (substance / chemical) that affects body chemistry / chemical reactions in the body

what is starch broken down into

sugars

Benedict colour change upon what ..

blue to green, yellow, orange, or brick-red upon heating, depending on concentration

colour change biuret solution

from blue to violet

Describe a method to investigate the effect of pH on the rate of starch breakdown by amylase.

•   add iodine solution to spotting tile

•   use measuring cylinder

•   (to) add amylase (solution), pH solution and starch (solution) together

•   start the timer

•   use pipette

•   (to) remove a drop of mixture at regular intervals (e.g. every 30 seconds)

•   add drop of mixture to iodine (solution)

•   if starch is present, mixture and iodine (solution) turns blue / black

•   continue until the iodine (solution) and the mixture remain yellow / orange / brown

•   record the time taken for the mixture to remain orange

•   repeat at different pH

•   compare times at each pH

(control variables):

•   volume of starch (solution) / amylase (solution) / pH solution / iodine (solution)

•   concentration of starch (solution) / amylase (solution) / pH solution / iodine (solution)

•   temperature

Suggest what happens to the breakdown of starch when it reaches the stomach.

 breakdown stops

because stomach produces / contains acid / has low pH

and amylase cannot work in acid / low pH

what is a enzyme

 a catalyst / speeds up a reaction1

it is a protein or it is specific or it has an active site