Biology Y11 mock

The types of pathogens

Bacteria

Fungi

Viruses

Protists

Bacteria

• single celled prokaryotic organisms

• reproduce rapidly in the body

• may produce toxins

• can be treated with antibiotics

Fungi

• single or multi-celled eukaryotic organisms

• grow on moist surfaces

• can be treated with anti-fungals

Viruses

• Tiny particles

• damage cells by reproducing inside them

• can be treated with anti-virals

Protists

• single celled eukaryotic organisms

• cannot usually be treated with antibiotics

Ways of transmission

• animals

• water

• food

• contact

• bodily fluids

• air droplet infection

Vector

an organism that transmits a pathogen from one organism to another.

Barriers to infection

• The eyes:tear glands make antiseptic liquid,blink reflex,eyelashes

• The nose:Hairs trap particles

• The skin:physical barrier,produces antimicrobial secretions

• Trachea and bronchi mucus:mucus traps pathogens,swallowed to stomach

• The stomach:produces acid

• Cuts:Blood clots

• Hair follicles:glands make antiseptic oil

Phagocytosis

ENGULF the pathogen

DIGEST the pathogen

DIFFUSE out the waste

Lymphocytes

ANTIBODIES binds to ANTIGENS with complementary receptors

When many pathogens are bonded with antibodies it is called AGGLUTINATION

Produce ANTITOXINS which neutralise toxins

Salmonella

pathogen- bacteria

symptoms- vomiting,diarrhoea,abdominal cramps

transmission- unhygienic kitchens,under cooked foods

treatment- antibiotics

prevention- vaccinated poultry,cooking foods properly

Gonorrhoea

pathogen- Bacteria

symptoms- burning pain when urinating,thick yellow/green discharge,infertility

transmission- sex (contact,bodily fluids)

treatment- antibiotics

prevention- contraception

Malaria

pathogen- protist

symptoms- fever,sweats,headaches,vomiting,diarrhoea

transmission- Vectors

treatment- antimalarial drugs

prevention- don’t get bit by mosquitoes

How do vaccines work?

1. Vaccines contain dead or inactive pathogens

2. Lymphocytes clone and produce antibodies

3. Some lymphocytes develop into memory cells

4. If a pathogen infects the body in the future,the response is FASTER,LARGER and LONGER LASTING

Herd immunity

If a large proportion of the population is immune to a pathogen,the spread of the pathogen is very much reduced.

What are monoclonal antibodies?

Identical copies of one type of antibody

How are monoclonal antibodies produced?

1. A mouse is injected with chosen antigen

2. The mouse then produces specific lymphocytes

3. The lymphocytes are removed from the mouse

4. These lymphocytes are fused with tumour cells

5. The hybridoma cell clones quickly

6. These clones release many identical antibodies

Discovery of drugs

Traditionally drugs were extracted from plants and micro-organisms

Penicillin was discovered by Alexander Fleming and came from a type of mould called penicillium.

Why do new drugs have to be trialled and tested before they can be used in medicine?

So they can be seen if they are stable,safe and effective.

Pre-clinical testing

Pre-clinical testing is where we test the drug in a lab on cells,tissues and live animals.Scientists try to see if it damages the cells.

Clinical trials

1. Using low doses- this is used to check for side effects

2. Finding the optimum dosage-they try it on a bigger group increasing dosage

3. Peer review-many experts examine the trail to check quality,importance etc

Blind trials and double blind trials

A double blind trial is where neither patient or doctor knows if the patient is receiving a placebo or the actual drug.However a blind trail is where the patient does not know whether they are receiving the placebo or not but the doctor does

Health

The state of physical and mental wellbeing

Factors affecting health

diet,stress,life situations,substance abuse,trauma,PAL level

Interactions of diseases

A virus living in cells can trigger some cancers.

Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.

Severe physical ill health can lead to depression and mental illnesses.

Defects in the immune system mean that an individual is more likely to suffer from infectious diseases.

Ion deficiency in plants

Nitrate deficiency causes stunted growth as nitrate ions are needed for protein synthesis and therefore growth.

Magnesium deficiency causes chlororsis as magnesium ions are needed to make chlorophyll.

Risk factors for disease

• diet

• exercise

• smoking

• obesity

What is the role of the stomata and guard cells?

To control gas exchange and water loss.

How and how often do bacteria multiply?

By simple cell division as often as every 20 minutes if they have enough nutrients and stay at stable temp.

Are monoclonal antibodies specific?

Monoclonal antibodies are specific to one binding site on one protein antigen.

They can therefore target a specific chemical or type of cell within the body.

Uses of Monoclonal antibodies

To treat some diseases

• For cancer the monoclonal antibodies can be bound to a radioactive substance,a toxic drug or a chemical which stops cells dividing

In research

• To locate or identify specific molecules by binding the antibodies to dye.

In laboratories

• Used to measure the levels of hormones and other chemicals in the blood.

Diagnosis

• In pregnancy tests they bind to hCG produced.

What is a risk factor?

Risk factors are something that can increase your risk for disease.

These can be

• aspect of someones lifestyle

• substances in the person’s body or environment

Risk factors for cardiovascular disease

• smoking

• high fat/cholesterol diet

• lack of exercise

Common risk factors

Smoking → lung disease/cancer and can cause tissue damage in unborn babies

Alcohol → liver damage and changed brain function,can cause premature birth and miscarriages

Carcinogens → can cause cancers (ionising radiation)

What are cells?

Cells are the basic building blocks of every living organism

What are sub-cellular structures in both animal and plant cells?

• Nucleus

• Mitochondria

• Cytoplasm

• Ribosomes

• Cell membrane

What are sub-cellular structures that only PLANT cells contain?

• Chloroplasts

• Cell wall

• Permanent vacuole

Function of the nucleus

Contains genetic material,DNA

Controls the activities of the cell

Function of mitochondria

Where aerobic respiration takes place

(provides energy)

Function of cytoplasm

Where most chemical reactions take place

It contains enzymes for this

Function of cell membrane

Controls the passage of substances in and out of the cell.

It contains receptor molecules.

Function of ribosomes

Where protein synthesis occurs

Uses RNA

Function of chloroplasts

These absorb light with chlorophyll and use this to complete photosynthesis.

This produces food.

Function of permanent vacuole

Filled with cell sap.

Used for storage and keeps shape of the cell

Function of cell wall

This supports the cell and strengthens it.

What is cellular respiration?

It is an exothermic reaction (transfers energy to the environment)

It is the process of transferring energy from glucose.

This is happening continuously in living cells.

The energy transferred allows all living processes to take place.

Where does aerobic respiration take place?

Mitochondria

Stages of the cell cycle

INTER-PHASE

Sub-cellular structures replicate

DNA duplicates

MITOSIS

Chromosomes line up and are pulled apart to opposite poles.Two nuclei form.

CYTOKINESES

Cell membrane and cytoplasm divides.

What is produced from the cell cycle?

TWO daughter cells.

These are identical.

Why is cell division important?

It allows growth and development of multicellular organisms.

What is osmosis?

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

What can osmosis do to Red blood cells?

In dilute solutions,it can cause animal cells to swell up and burst.

This is called Lysis.

If there is a loss of water from osmosis the red blood cell will shrink.

What happens to a plant cell in pure water?

The cell contents push against the cell wall and the cell becomes turgid.

What happens to a plant cell in a salty solution?

The cell contents lose water by osmosis.They shrink and pull away from the cell wall.

The cell becomes flaccid.

What happens to a plant cell in a very salty solution?

The cell undergoes full plasmolysis as the cells lose more water.

What happens to a plant cell when the sugar content increases in a solution?

As the concentration of sugar increases so does the percentage change in mass.

How would you find the concentration of cell cytoplasm in the investigation of Osmosis?

It can be estimated by reading off the concentration of sucrose at the point where the line of best fit crosses.

What happens in CHD?

Layers of fatty material build up inside the coronary arteries,narrowing them,reducing the blood flow and resulting in a lack of oxygen to heart cells.

What are statins?

They are drugs used to reduce the blood cholesterol level.This reduces the rate of build in arteries.

What are the pros and cons of Statins?

Pros

• reduce rate of build up

• decrease risk of heart attack

Cons

• Have side effects

• Have to be kept up with

What are stents?

They are metal mesh paced in an artery and then opened up by inflation of tiny balloon to hold a narrowed blood vessel open.

What are the pros and cons of Stents?

Pros

• No anaesthetic required

• Relatively cheap

Cons

• Ineffective against severely blocked or narrowed arteries

What are pathogens?

Microorganisms that cause infectious disease

What happens in Phagocytosis?

1. Phagocyte engulfs the pathogen

2. The pathogen is digested

3. These broken down materials diffuse out

What do antibodies do? (the proccess)

1. Lymphocyte detects non-self antigen and releases antibodies

2. The antibody binds to the antigen with the complementary shape

3. Many pathogens and antibodies are bonded.This is agglutination.

What do antitoxins do?

1. Lymphocyte detects toxins and releases antitoxins

2. These neutralise the toxins

What is the equation for photosynthesis?

carbon dioxide + water  →  glucose + oxygen

6CO₂+6H₂O→C₂H₁₂O₂+6O₂

What might the glucose produced in photosynthesis be used for?

• respiration

• storage by being converted to starch

• to produce lipids for storage

• to produce cellulose and strengthen cell wall

• used to produce amino acids for protein synthesis

What effect does light intensity have on the rate of photosynthesis?

As the light intensity increases so does the rate of photosynthesis.

What effect does temperature have on the rate of photosynthesis?

As temperature increases so does the rate of photosynthesis.

However after a certain temp enzymes denature and therefore the rate decreases.

What effect does carbon dioxide concentration have on the rate of photosynthesis?

An increase in concentration causes an increase in the rate of photosynthesis.

What effect does the amount of chlorophyll have on the rate of photosynthesis?

Large amounts of chlorophyll means an increased rate of photosynthesis.

What is translocation?

Transport of dissolved sugars from leaves to all other plant cells.

What happens in Mitosis?

1. DNA is copied

2. Chromosomes begin to align at the equator of the parent cell

3. The chromatids are separated to different poles by spindles

4. Chromosomes recoil up and form nuclei

How to calculate the length of stages in cell cycle:

Number of cells in particular stage

Total number of cells              x length of cell cycle

What is meristem tissue?

It is a tissue in plants that is able to differentiate into any type of plant cell and is able to do this throughout the entire life of the plant.

What are the uses of meristems in plants?

• Produce clones of plants quickly and economically.

• Rare species can be cloned to protect from extinction.

• Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.

What is a tissue?

A group of cells with a similar structure and function.

What are plant cells,prokaryotic or eukaryotic?

Eukaryotic.

They have a cell membrane,cytoplasm and genetic material enclosed in a nucleus.

What are bacteria cells,prokaryotic or eukaryotic?

Prokaryotic.

They are much smaller in comparison and they have cytoplasm and a cell membrane surrounded by a cell wall.Also,their genetic material is not enclosed by a nucleus. It is a single DNA loop.

What is the word equation for aerobic respiration?

Glucose + Oxygen → Carbon Dioxide + Water + …………………………………………………………..Energy release

What is the word equation for anaerobic respiration?

Glucose → Lactic acid + small energy release

Why is there much less energy transferred with anaerobic respiration?

Because the oxidation of glucose is incomplete.

How does the body react to the increased demand for energy during exercise?

The heart rate,breathing rate and breath volume increase to supply the muscles with more oxygenated blood.

This enables increased cellular respiration so more energy transferred to meet the demands of the muscle cells.

What happens when, during exercise, not enough oxygen is supplied to the muscle cells?

Anaerobic respiration takes place in muscles.

This causes a build-up of lactic acid and creates an oxygen debt.

During long periods of vigorous activity muscles become fatigued and stop contracting efficiently.

What is oxygen debt?

It is the amount of extra oxygen the body needs after exercise to react with the accumulated lactic acid and remove it from cells.

What happens to the lactic acid after exercise?

Blood flowing through the muscles transports the lactic acid to the liver where it is converted back into glucose.

what is the heart?

An organ which pumps blood around the body in a double circulatory system.

Identify the numbers on the heart.

1. Pulmonary artery

2. Pulmonary vein

3. Aorta

4. left atrium

5. left ventricle

6. right ventricle

7. Vena cava

8. right atrium

What do the group of cells called ‘pacemakers’ do?

they control the natural resting heart.

They are located in the right atrium.

Describe how blood flows through the heart.

Blood flows into the two atria from the vena cava and pulmonary vein.

The atria contract,pushing the blood into the ventricles.

The ventricles contract, forcing the blood into the pulmonary artery and the aorta,and out of the heart.

The blood then flows to the organs through arteries, and returns through veins.

The atria fill again and the whole cycle starts over.

Why is the left side of the heart thicker?

As there is more muscle to generate a higher pressure to pump blood a longer distance.

What is the function of arteries?

To transport blood away from the heart.

What is the function of veins?

To transport blood towards the heart.

What is the function of capillaries?

They allow exchange of materials between blood and tissues.

What is the structure of arteries?

• Thick outer wall

• Thick layer of muscles and elastic fibres to maintain and withstand the high pressure and stretch and recoil as each pulse passes

• smooth lining

• small lumen

What is the structure of veins?

• smooth lining

• large lumen (to prevent friction)

• fairly thin outer wall

• thin layer of muscles and elastic fibres

• contain valves to stop the back-flow of blood

What is the structure of capillaries?

• very small lumen

• wall made of a single layer of cells

• permeable walls to allow easier diffusion

Why do red blood cells contain haemoglobin?

Because it binds to oxygen so they can transport it.

What are the advantages of a heart transplant?

• lasts long

• effective