Biology Paper 1 aqa gcse

doesn't cover all information, only stuff idk.

What is surface area of alveoli?

About 75 meters squared for humans.

What features of alveoli make it good for gas exchange?

thin walls, big surface area, moist lining for dissolving gases, good blood supply.

What the projections in small intestines called?

Villi (singular form villus)

What the typical sub-cellular structures in animal cell?

Nucleus, cytoplasm, mitochondria, ribosome, cell membrane

What is the nucleus?

contains genetic material, controls activites of cell

What is the mitochondria?

where most aerobic respiration takes place, releases energy in order for cell to work properly

What is the cytoplasm?

gel like substance, where most chemical reactions are. contains enzymes which controls these reactions.

What is the cell membrane?

supports cell, controls what goes in/out of cell.

The typical sub-cellular structures in plant cell

Cell wall, permanent vacuole, chloroplast

What is the cell wall?

rigid, made from cellulose. strengthens and supports cell.

What is the permanent vacuole?

contains cell sap made from weak solution of salt and sugar.

What is the chloroplast?

where photosynthesis occurs, makes glucose for plant, contains green substance called chlorophyll, which absorb light energy for photosynthesis.

Features of villi?

Increase surface area, single layer of surface cells, good blood supply.

Where are the villi located?

small intestine

What is in the villi?

Network of capillaries under layer of cells, circular muscles are the dots in muscle under capillaries, longitudinal muscle under circular muscle.

Typical structure of bacterial cell.

Plasmids - circular loops of DNA

Cytoplasm, Cell wall, Genetic material not enclosed in nucleus.

Gas exchange in leaf?

CO2 diffuses into air spaces within leaf, then to cells where photosynthesis happens(upper leaf).

Walls of cells inside leaf form exchange surface.

Where does water vapour diffuse out of in the leaf?

Water vapour mostly diffuses out of stomata, and some out of whole leaf(surface).

How is gas exchange made more quicker in leaves?

Flattened shape of leaf adds area to exchange surface. Air spaces inside leaf add area to surface.

What happens if plant loses water from leaf faster than replaced in roots?

stomata closes by guard cells

What happens to the leaf without guard cells?

would soon wilt

When drawing cells after looking through microscope, how much of page should it fill, and what should you do in the process?

drawings should cover at least half page, with labels, title, no shading/colouring, unbroken and clear lines, also write down magnification, you observed with.

What is differentiation?

process where cells become specialised for its function, by developing different sub-cellular structures, and turn into different types of cells.

When does differentiation occur in organisms?

Most of the time when organisms develop.

Differentiation in animal cells?

Lose the ability to differentiate at early stage after differentiation.

Differentiation in plant cells?

don't lose ability to differentiate.

Differentiation for animals, that don't lose ability to differentiate.

called mature animals, differentiation only use for repairing/replacing faulty cells.

The main function of sperm cell?

carry the male DNA to female DNA

Typical sperm cell structure?

Streamlined head, tail, acrosome, mitchondria in middle part of the body.

What is the acrosome?

top of head, enzyme filled(penetrate outer egg), nucleus inside head, contain one set of genetic material.

Function of nerve cell?

carry electrical impulses around body

Typical structure of nerve cell?

Long shape to connect with other nerve cells to carry impulses, cell body, sheath, axon

What is a dendrite?

little arms at end of nerve cell

What is a cell body?

contains nucleus(nerve cell)

What is the sheath?

little parts that make up axon.

Main function of muscle cell?

contract quickly

Typical structure of muscle.

Long cell to contract easily, nucleus bumps on top of muscle cells, mitochondria inside surface of muscle to release energy for contraction.

Protein fibres in muscle cells which cause contraction in muscle cell. And can contract themselves.

Main function of root hair cell?

absorb mineral ions to it's already sufficient enough cell of mineral ions, and to also absorb water

Typical structure of root hair cell?

Cells in surface of plant roots which grow into long hairs, indicated by picture of root hair cell.

This gives them huge surface area for absorption.

Lots of mitochondria to release energy in order to pull concentrated solution in soil to root hair cell.

Stem cell features?

divide into more stem cells differentiate into different types of cells, depending on what instructions they're given.

Found in early human embryo, umbilical cord of newborn baby, some organs and tissues called embryonic stem cells

Where are stem cells found?

Found in early human embryo, umbilical cord of newborn baby, some organs and tissues

What are stem cells called found in the early human embryo?

embryonic stem cells.

What type of age group also have stem cells?

Adults

Adult stem cell features?

Found in certain places such as bone marrow, some organs or tissues only differentiate into certain cells such as blood cells.

What can both types of stem cells be used for?

grown in lab to produce clones, genetically identical to each other, and to differentiate into specialised cells for medicine or research.

Adult stem cells of healthy person can be used to replace faulty blood cells

What can embryonic stem cells be used for?

Insulin producing cells for diabetes, nerve cells for people paralysed by spinal injuries.

What other type of cloning for stem cells is there?

Therapeutic cloning

Typical features of therapeutic cloning?

Embryo made to have same genetic information as patient, so stem cells produced won't be rejected by patients body because both the patient and stem cell have same gene.

Risks of therapeutic cloning?

Stem cells grown in lab may be contaminated with virus, can be passed to patients making them sick.

Risks/problems people have with stem cells?

viral infection, people with religious/ethical objections

Reasons people are against stem cell research?

Researching using human embryos is possible cost of one's life.

Curing patients who are suffering is more important than rights of embryos.

embryos in research often unwanted from fertility clinics, which if weren't used for research would be destroyed.

feel scientists should focus more on other sources of stem cells, so people won't have to be help with embryos.

Where are stem cells found in plants?

Meristems in roots and shoots.

What does the nucleus contain in form of?

Genetic material in form of chromosomes, which are coiled lengths of DNA molecules (at the start when cells not divide(mitosis), DNA molecules are in long strands).

Features of a chromosome?

Carry large number of genes, which each have code to make different proteins, that control development of different characteristics.

How many copies of each chromosome does a body cell normally have?

2

Features of dividing for cells?

Called mitosis:

Can be used to grow or repair cells

Cell fibres pull chromosomes apart

The end of mitosis results in 2 new cells identical to original cell with same number of chromosomes.

Where does mitosis happen?

multicellular organisms.

do all cells go through mitosis at the same time?

no, the body controls which cells to divide and when.

Where does water go in osmosis?

Through partially permeable membrane

Where can active transport also happen?

In humans such as taking glucose from gut, and from kidney tubules.

How is urea taken out of body?

Urea, which is waste product from breakdown of proteins, diffused from cells into blood plasma for removal from body by kidneys.

Exchanging gas in single celled organisms?

efficient, because gas directly diffuses into/out of them.

They have larger surface area/volume ratio.

Which is why enough gas can be exchanged to supply volume of organism

How does gas pass through fish(gas exchange)?

Water containing oxygen enters fish through mouth, then gills.

As this happens oxygen from water diffuses into blood in gills and carbon dioxide diffuses from blood into water.

How is gas exchange made faster in fish?

Gills are exchange surface in fish

Each gill made of thin plates called gill filament, adds surface area.

Gill filament covered in tiny structure called lamellae, adds surface area.

Lamellae have blood capillaries, thin surface layer of cells for quick exchange.

Blood flows through lamellae in one direction, and water flows over in the other.

Maintains large concentration gradient between water and blood.

Where is the concentration of oxygen higher in water or blood (fish)?

water

Enzymes?

Made from large proteins(chains of amino acids folded to form unique shapes).

A biological catalyst, increases speed of reaction without being changed/used up.

Used in digestion, made from cells, then released to gut.

Used in digestive system made from specialised cells in gland/gut lining.

What is the optimum pH that all enzymes work best at?

7, but not always.

What is pepsin?

enzyme used to break proteins in stomach. Peak pH=2

What is it called when a subtrate tries to fit in active site?

induced fit.

Effect of pH activity experiment Amylase?

Boil water to 35 degrees (keep temp constant).

Put drops of iodine solution into spotting tiles.

1cm cubed of amylase, buffer solution of pH 5 into boiling tube for 5 mins.

Use diff pipette to add 5cm cubed starch solution into boiling tube and mix, then start stop clock, as well as adding the solution to the tiles every 30 secs, and time how long it takes for amylase to break down starch.

What is lipase?

break down lipid into glycerol/fatty acid

made:pancreas, small intestine

What is amylase?

carbohydrase. Break down starch into sugars:maltose, glucose, dextrins

made: salivary gland, pancreas, small intestine

What is protease?

called pepsin in stomach. break down protein into:amino acid, peptide

made:stomach, pancreas, small intestine.

What does the body do with broken down stuff?

products of digestion, can make new carbohydrate, proteins, lipids. Glucose made is use for respiration.

Food test preparation?

Break up food to beaker, then add distilled water. Stir to dissolve food, then filter to get rid solid bits.

What should you do before food tests?

Food test preparation.

Except for lipid test.

testing for lipid?

5cm cubed food, 3 drop Sudan III stain solution to test tube, then shake.

Result: Sudan 3 stains lipid

Top layer red/bottom clear=present

Tube sample clear =no present.

testing for protein?

2cm cubed food/biuret solution to test tube, then shake.

Result: blue=present

Purple=no present

testing for starch?

5cm cube food, few drop iodine solution to tube, then gently shake.

Result: blueblack=present

Brownorange=no present

testing for sugars?

5cm cubed food, 10 drop Benedict reagent to tube.

Boil water to 75 degree. Wait 5min Results: (ascending) blue, green, yellow, brickred

sudan III stain solution precaution?

flammable

benedicts reagent precaution?

water bath experiment too hot

Biuret reagent precaution?

chemicals inside are dangerous, if spill on skin, wash off

Iodine solution precaution

irritant to eyes

Lungs

Thorax=top part body, separated from low part by diaphragm.

Lungs=big sponge protect by ribcage surround by pleural membrane.

What is the system called where your heart rate is?

circulatory system

What is an artificial pacemaker?

same as biological pacemaker, but implanted underskin, with wire going to heart, which spread impulse. For patient with irregular heartbeat.

How does the pacemaker control your resting heart rate?

Produce electrical impulse, spreads to surrounding muscle cell, causing them to contract, and make regular heartbeat

What is the resting heart rate controlled by?

group of cells in right atrium, act as a pacemaker

what is the wall of heart made of?

muscle tissue

What is another name for the circulatory system in humans and why?

double circulatory system, because blood travel through heart 2x on each circuit.

Features of white blood cell?

Have nucleus

Disease in the heart?

cardiovascular disease=disease of heart or blood vessel

Stent features?

Effective long time, recovery from surgery quick,

risk:complication in surgery (heart attack, infection, blood clot near stent=thrombosis.

Cholesterol features

Essential for body to function, too much of bad/LDL cholesterol=bad

much LDL in bloodstream=fat in artery

What is a statin?

drug reduce/slowdown growth of LDL in bloodstream=reduce risk(stroke, coronary, heart attack), increase HDL cholestrol in bloodstream. HDL remove LDL from blood. can help other disease.

What is a negative of statins?

negative side effect(headache)serious side effect=kidney fail, liver damage, mem loss, effect of statin not instant.

Artificial heart&valve&blood?

Surgery=bleed&infection

Artificial not work healthy as natural heart, could wear out or motor fail. Blood flow=not smooth, cause clot, lead to stroke. Patient need take drug to thin blood do clot and stroke no happen.

Valve surgery less problem, still lead to blood clot

If lose lot blood, heart still pump remain blood cell, as long as volume of blood topped.

Artificial blood=blood sub(saline a salt solution)replace lost vol blood, replace function of red blood cell. Safe if no air bubble in blood, can keep people alive with 2/3 blood gone.

Patient with artifi blood, will have enough time for new red blood cell generation.

What is a causal mechanism?

a factor that makes a disease more likely to occur & reason is known.

What is health?

State of physical and mental well-being