B2- Organisation

What are cells

the basic building blocks that make up all living organisms.

What is the order of how cells become organ systems

Cells > Tissues > Organs > Organ Systems

Is a leaf a tissue?

No its an organ

Name 3 tissues

* Muscular tissue
* Glandular tissue
* Epithelial tissue

Name 3 organs (tissues that work together to perform a function)

* Stomach
* Pancreas
* Liver

What is an organ system

A group of organs working together to perform a particular function e.g. the digestive system breaks down and absorbs food it contains:


1. Glands e.g. pancreas and salivary glands which produce digestive juices
2. The stomach and small intestine , which digest food.
3. The liver, which produces bile.
4. The small intestine, which absorbs soluble food molecules
5. The large intestine, which absorbs water from undigested food leaving faeces

What are Enzymes

Enzymes are catalysts produced by living things

What is a catalyst

A substance which increases the speed of a reaction without being changed or used up in a reaction

How do enzymes connect to substrate

On the enzymes active site as they have to fit to the substrate perfectly

How does the active site change slightly to make the connection to the substrate tighter

It changes shape so the substrate can bind to it which is called an induced fit

What changes the rate of an enzyme-catalysed reaction

The temperature and PH of conditions

What happens to an enzyme if it gets too hot

Its active site starts to deform causing it to denature

How can you investigate the effect of PH on Enzyme Activity

The effect of pH on amylase through iodine placed in spotting tiles

Solutions filled test tubes of

Tube A- starch solution (2cm cubed)

Tube B- amylase solution (2cm cubed)

Tube C- pH 5 buffer solution (2cm Cubed) (used to control pH

then leave all solutions in a water bath set at 30 degrees Celsius for 10 minutes to make sure they are the correct temperature.

Then mix all the solutions together into one test tube and place straight back into the 30 degree water bath and start the stop watch

then after 30s us a pipette to transfer a drop of solution into the spotting tiles with iodine in it

If the solution turns blue black it means it still contains starch

then every 30s we keep testing the iodine until it stays iodine which indicates to us that starch is no longer present in the solution meanng the amylase has broken down the starch. (Reaction completed)

Repeat the experiment two or 3 more times with different pH buffers to find whichever is the most efficient. (Reacts in the least amount of time)

What is an issue with this experiment

Difficult to tell when reaction has finished can be solved by getting other peoples opinion.

What is amylase

A carbohydrase which breaks down starch into maltose and other sugars

* It is produced in the salivary glands, the pancreas and the small intestine

What is protease

It converts proteins into amino acids

* It is produced in the stomach, pancreas and small intestine

What is Lipase

Converts Lipids into Glycerol and fatty acids

* Produced in the pancreas and small intestine

What is and Bile and where is it produced

Bile neutralises the stomach acid in order to allow enzymes in the small intestine to work properly as bile is alkaline and the enzymes there work best in alkaline.

Additionally it emulsifies fats which means to break them down into smaller droplets increasing their surface area allowing them to be digested faster.

Produced in the liver stored in the gallbladder and released into the small intestine

What are the purposes of enzymes around the body

What is the Benedict’s test for and what are the colour indicators

Sugar which when benedict’s is added the solution is then placed in a 75 degree Celsius water bath and left for 5 minutes

When first added it will turn blue then to green, yellow and at most brick red depending on the amount of sugar.

What is Iodine test for and what are the colour indicators

Starch if present colour will change blue black

If not brown orange

What is Biuret A and Biuret B

Proteins. Prepare a sample of food and transfer 2cm cubed to a test tube add 2 cm cubed of biuret solution. If protein present solution will change from blue to purple

What is the Sudan III test for

Lipids

What are stents and the pros and cons

Stents are inserted into the coronary arteries to keep the arteries clear preventing fat blocking the artery and preventing blood from flowing through.

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Stents Positives

Long term keep the arteries open and lower risk of a heart attack

quick recovery from surgery

Negatives

Surgical procedure which is risky

cauld cause blood clots thrombosis

heart attack

infection

Statins

Statins are a drug taken to reduce the production of bad cholesterol (LDL) in the bloodstream which slows down the production of fatty deposits in the arteries

Positives

\-No surgical procedure required

\-Reduces chances of strokes, heart attacks and CHD

\-Increases amount of ‘good’ cholesterol produced (HDL)

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Negatives

\-Long term drug which can be forgotten to be taken

\-Can cause side affects like headaches or serious ones like kidney failure, liver damage or memory loss

\-effect of statins take time to kick it

What can be made artificially

Hearts, Blood and valves

Advantages of artificial heart

Less likely to be rejected than donor but tehy don’t work as well as natural ones and can lead to bleeding and infection. Patient also has to go thinners which causes more bleeding in accidents

Advantages of artificial valves

Replace old or stiffened valves with mechanical or biologoical ones but it is major surgery

Advantages of artificial blood

Can be used even when someone has lost 2 thirds of their blood in order to support their body until they are able to produce new red blood cells

What is cancer

Uncontrolled growth and division of cells caused by the formation of a tumour

What are the two types of tumours

Benign- Stays in one place and grows until there is no more room and is not cancerous so not usually dangerous

Malignant- Tumour grows an spreads to neighbouring healthy tissue. Cells break off and spread out through the bloodstream causing the formation of of secondary tumours around the body on healthy tissue

What are the risk factors which increase possibility of cancer due to lifestyle?

Smoking- linked to lung cancer as well as bowel, mouth, stomach and cervical cancer

Obesity- Linked to many different cancers including bowel, liver and kidney

UV exposure- Skin cancer sunny climate or sun beds

Viral infection- Infection with hepatitis B and C can increase risk of liver cancer this can depend on lifestyle e.g. sharing needles or having unprotected sex

Risk factors linking to Genetics

Faulty genes

Mutations in BRCA genes have been linked to an increase likelihood of breast and ovarian cancer

What are 3 organs in a plant

* Stems
* Roots
* Leaves

What tissues are the leaf made up of as an organ

Waxy cuticle- stops leaf from drying out

Upper Epidermis- transparent to allow light through to meso

Palisade mesophyll- contains tons of chloroplast Air space

Spongy mesophyll tissue- air space to allow carbon dioxide to diffuse from the stomata to the palisade cell. Oxygen also does the opposite

Epidermis tissue Stomata- Control amount of water leaves leaf Guard cell

What is the purpose of the xylem

transports water from the roots to the stem and leaves and some of it is used in photosynthesis it also transports dissolved mineral ions such as magnesium which is used to make chlorophyll

What is the purpose of the phloem

Transports dissolved sugars from the leaves to the rest of the plant sugars are used in respiration also stored as starch

This movement of sugars through the phloem is called translocation

What is meristem tissue

Growing in tips roots and shoots they contain stem cells

How are the xylem and phloem adapted for their purpose

Phloem- pores in the end walls to allow cell sap through goes in both directions

Xylem- made up of dead cells joined end to end strengthened by lignin (no end walls

What is transpiration

The evaporation of water out of the leaf cell water vapour diffuses through the air spaces of the spongy mesophyll and out through the stomata. The water lost is then replaced by water coming up through the xylem which is drawn from the roots. Transports magnesium which is important for the plant.

Cools the leaf down in hot weather

What increases the rate of transpiration

* Increase in temperature,
* dry conditions,
* windy conditions (removes water vapour)
* increase in light intensity (increases rate of photosynthesis)

Stomata

Have two guard cells which swell when light intensity is high to allow carbon dioxide to diffuse into the leaf when in hot conditions the stomata close to reduce water loss but it means photosynthesis can’t take place.