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Magnification calculation
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What do eukaryotic cells all have
A nucleus
Where is a prokaryotic cells dna found
Plasmid (loop of dna)
What is the cytoplasm
The liquid that makes up the cell where most chemical reactions take place
What do plant cells have which animal cells do not
Chloroplasts
Cell wall
Perminant vacuole
How many pairs of chromosomes are found in every nucleus and what are these cells called
23
Diploid cells
What are gametes
They have half the number of chromosomes
23 not 23 pairs
These are called haploid cells
What are diploid cells made for and how do they do it
Growth and repair by duplicating via mitosis
What happens during mitosis
Generic material is duplicated aswell as ribosomes and mitochondria
The nucleus breaks down and one set of each chromosome pair is pulled to opposite sides of the cell
The new nucleus forms each of these to house the copied chromosomes which makes two identical cells
What are stem cells
Cells which haven’t specialized yet
Where are stem cells found
Human and animal embryos and plant meristems
What is a plant meristem
The top of the shoot
Where are stem cells made
Bone marrow
What can stem cells be used for
Combat diabetes and paralysis
What are embryo clones
Identical copies of the patients genes which can be used to treat conditions without the body rejecting them
Why can cloning plants be used
To preserve species or produce crops with desired traits
What is diffusion
Movement of particles from an area of high to low concentration which dosent require energy
Where does diffusion happen
Across a semi permeable membrane if the holes are large enough for molecules to move through
Water can pass through however glucose cannot
What is osmosis
The movement of water across a semi permeable membrane to balance the concentration
How can rate of diffusion and osmosis be increased
Increasing difference in concentrations
Increasing temp
Increasing suraface area
What is active transport
Where cells use energy to move substances across a cell membrane
What is a tissue
When similar cells work together to perform a function
What does a tissue form
Organs
What do organs do
Work together in an organ system
What does the digestive ststem do
Breaks down food into useful nutrients for your body to use
What do bile and enzymes do
Work together in the small intestine to break food down further
What does the stomach do
Contains hydrochloride acid and enzymes that break down food
What are enzymes
Biological catalysts that break down large molecules into small ones which can be absorbed into the blood stream
What is amylase
The enzyme that breaks down starch into glucose found in small intestine and saliva
What do carbohydraes break carbohydrates into
Simple sugars
What do protease break down proteins into
Amino acids
What do lipids break Lipaes into
Glycerol and fatty acids
How do enzymes work
Substrate binds to the enzymes active site which only happens if the substrate is the right shape
What does denatured enzyme mean
When the active site changes shape and the substrate cannot bind with it
What colour does iodine change to
Orange to black in the presence of starch
What colour does Benedict’s solution change
Blue to orange if sugar is present
Biuret regent colour changes
Blue to purple if proteins are present
Ethanol colour changes
Turns cloudy in the presents of lipids (fats)
What are the alveoli
Air sacs where blood diffuses into the blood vessels around it
Why do alveoli have large surface area
So gas exchange can happen at a faster rate
What does oxygen bind to
Haemoglobin in red blood cells which are transported around the body into cells to be used for respiration
What happens to carbon dioxide made from respiration
Dissolved into the plasma of the blood which diffuses into the lungs and is exhaled
What’s a double circulatory system
Blood enters the heart twice for every time it is pumped around the body
Where does de oxygenated blood from the body enter
Right side of the heart through the vena cava into the right atrium
What does the valve between the right atrium and right ventricle do
Prevents backflow to stop deoxygenated blood from going back into the body
How does the deoxygenated blood get to the lungs
Enters the vena cava travels to the right atrium then to the right ventricle and exits out of the pulmonary artery
What path does the oxygenated blood take around the heart
Enters through the pulmonary vein from the lungs into the left atrium then into the left ventricle and out into the body through the aorta
What are the walls like on the left side of the heart
Thicker walls becuase it has to pump blood to the whole body.
What do the group of cells near the right atrium do
Create electrical impulses ther cause heart muscles to contract and for the heart to beat
What happens if your cells in the heart don’t work
Given an artificial paise maker
What do arteries do
Carry oxygenated blood away from the heart
What are the adaptation of the artery
Thick walls
Thin linen to withstand high pressure
What does the vein do
Carrie’s blood back to the heart
What are the adaptations of the vein
Thin walls and wide lumen
Valves to prevent backflow
What do capillaries do
They are one cell thick and allow fast diffusion between blood cells
How does coronary heart disease occur
When the artery supplying blood to the heart becomes blocked
What are stents
Little tubes inserted into blood vessels to keep them open so blood flow can continue
What are statins
Drugs that reduce cholesterol which reduces fatty deposits
What must a communicable disease be caused by
Pathogens
What are non communicable disease
Cause comes from inside the body
How is cancer formed
Uncontrollable division of cells which leads to tumors
What are benign cancers
Don’t spread to the body and are easy to treat
What are malignant cancers
When cancerous cells spread through the body
What is the xylem
A continuous tube that Carrie’s water and dissolved mineral ions upward
What happens at the roots
Water enters through osmosis mineral ions by active transport
What is the phloem
Carrie’s cells that transport sugars and food up and down the plant which is translocation
How can the rate of transpiration be increased
Air movement
Temp
Decreased humidity
What is the waxy cuticle
Waterproof to stop water loss from the top of the lead
What is the upper epidermis
Transparent to let light through
What is the palisade mesophyll
It is where most photosynthesis takes place
What are the spongy mesophyll
Gaps which facilitate gas exchange
They have a large surface area
What is the lower epidermis
The bottom layer of the leaf which has holes in called the stomata where substances inter and exit
What do bacteria do
Release toxins which damage cells
What are lymphocytes
Produce antitoxins which neutralize the poison pathogens produce which make antibodies which stick to antigen on the pathogen stopping them from affecting more cells
What do phagocytes do
Ingest and engulf pathogens
What is a vaccine
A dead version of a virus which is injected into the body so you can gain immunity from the illness
What do antibiotics kill
Bacteria not viruses
What happens the more u use antibiotics
Cells become resistant to them which means nothing really happens
What is a double blind trial
When doctors do not know which drug is which to eliminate bias
What is the word equation for photosynthesis
Water + carbon dioxide (arrow) glucose + oxygen
What is the rate of photosynthesis increased by
Temp
Light intensity
Co2 concentration
What is glucose used for
Respiration
Making fat to store energy
Making cellulose
What is photosynthesis
When plants use light energy to transform it to chemical energy
What does respiration provide energy for
Chemical reactions
Warmth
Movement
What is aerobic respiration
And give the word equation
Excersise done with oxygen
Glucose + oxygen (arrow) water + carbon dioxide
What is anaerobic respiration
Occoirs when there is a lack of oxygen
It occoirs during intense Excersise
Lactic acid is broken back down into glucose by the liver using oxygen
What is metabolism
The sum lf all chemical reactions in a cell
Can be used for respiration
How would you carry out a practical for food tests
Add 2 to 3 droplets of each sample
Observe the colour change
Heat the Benedict’s sample in a water bath only
What is a control variable
Stays the same
What is the independent variable
The one you change
What is the dependant variable
The ome you measure
Write the method for the osmosis practical
Cut potato in lengths of 2cm
Use a measuring cylinder to measure 5 different concentration samples
Label each test tube
Measure the starting mass of the potato slice and place in the solution
Record in a table
Leave for 24 hours
Record final mass and calculate mass change
Microscopy practical method
Remove 1 layer of skin with tweezers
Place flat onto microscope slide to avoid air bubbles
Add 2 drop of iodine
Place cover strip at 45 degreees and lay on top to remove bubbles
Plsce slide onto the stage and begin to focus
Write a method for the photosynthesis practical
Add sodium hydrogen carbonate to beaker of water
Add pondweed to test tube of water
Place test tube upside down over funnel
Use ruler to measure 100cm, place light here
Leave for a minute and count bubbles
Move 10cm closer leave for 1 min and count again
Repeat until 10cm
Record results in a table
What is the method for the enzyme activity practical
Add 2 drops of iodine in each well of spotting tile
Add 2cm cubes of PH, startch and buffer test tube maintain temp using water bath
Start timer every 30 seconds use a rod to remove a solution sample
Add to well. Observe colour change and repeat every 30 seconds until no colour change is observed
Repeat with different PH
Write down the method for the food test practical
Add 2-3 drops of each sample
Observe colour change
Heat samples in water bath for Benedict’s only
