Biology Terms

organisms whose cells lack a nucleus and other organelles

any cell or organism that possesses a clearly defined nucleus

controls the activities of the cell

where aerobic respiration takes place

where most of the chemical reactions take place

controls the passage of substances into and out of the cell and contains receptor molecules

where protein synthesis occurs

surrounds the plasma membrane of plant cells and provides strength and protection

absorb light (using chlorophyll) to make food by photosynthesis

filled with cell sap to help keep the cell turgid

prokaryotic, have cytoplasm and a cell membrane and wall, no nucleus, genetic material found in a DNA loop and rings of DNA plasmids

a group of cells that have similar structure and that function together as a unit

0.01m

0.001m

0.000001m

0.000000001m

micron, 1/1000000 of a meter

chemical reactions that release energy

the process of converting glucose into a form of energy that can be used by cells

with oxygen

without oxygen

take place aerobically or anaerobically to transfer energy

glucose + oxygen → carbon dioxide + water + energy release

glucose → lactic acid

much less energy is transferred than in aerobic respiration

reacts to the increased demand for energy

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

The incomplete oxidation of glucose 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.

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

both are catabolic processes that takes place in all cells and releases energy and carbon dioxide

one needs oxygen, one doesn’t and they produce different products

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

it allows for the absorption of water, making the cells turgid. The water can also carry dissolved ions and chemicals

an organ that pumps blood around the body in a double circulatory system

Heart to lungs to heart, heart to rest of body to heart

pumps blood to the lungs where gas exchange takes place

thicker wall with more muscle to generate a higher pressure to pump blood a longer distance to the rest of the body

a group of cells located in the right atrium that act as a pacemaker.

large diameter, thin outer layer, has elastin and contains valves to stop blood from flowing in the wrong direction, carries deoxygenated blood back to the heart to be pumped to the lungs for oxygen

thick wall, doesn’t stretch, carries oxygenated blood away from the heart at a high pressure

narrow, thin cell walls to allow for fast and easy substance exchange, large surface area, gets blood to areas of the body required for ‘exchange’

binds to oxygen to transport it from the lungs to the tissues.

narrowing them, reducing the flow of blood and resulting in a lack of oxygen to the heart cells.

used to keep the coronary arteries open

used to reduce blood cholesterol levels which slow down the rate of fatty material deposit.

artificial hearts are occasionally used to keep patients alive whilst waiting for a transplant or allow the heart to rest as an aid to recovery.

carbon dioxide + water → glucose + oxygen

endothermic reaction where light energy is transferred from the environment to the chloroplasts by light

the rate of photosynthesis will increase because there is more light available to fuel the reactions of photosynthesis

As temperature increases the number of collisions increases, therefore the rate of photosynthesis increases

carbon dioxide is one of the reactants in photosynthesis so if the concentration of carbon dioxide is increased, the rate of photosynthesis will increase

light is an agent required for photosynthesis and leaves with more chlorophyll are better able to absorb light, therefore the rate of photosynthesis increases with the presence of more chlorophyll

cause infectious diseases: viruses, fungi, bacteria and protists

direct contact, water or air

produce toxins that damage tissues and make us feel ill.

• Salmonella -food poisoning spread by bacteria ingested in food, or on food prepared in unhygienic conditions. Symptoms of fever, abdominal cramps, vomiting and diarrhoea are caused by the toxins secreted by the bacteria. In the UK, poultry are vaccinated against Salmonella to control spread. 

• Gonorrhoea -STD causing symptoms of thick yellow or green discharge from the vagina or penis and pain when urinating. Easily treated with the antibiotic penicillin. Spread can be controlled by using barriers methods of contraception

• Malaria -symptoms of recurrent episodes of fever, which can be fatal. Spread is controlled by preventing the mosquito vectors from breeding and by using mosquito nets to avoid being bitten.

Uncontaminated cultures of microorganisms are required for investigating the action of disinfectants and antibiotics.

• Petri dishes and culture media must be sterilised before use.

• Inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a flame.

• The lid of the petri dish should be secured with adhesive tape and stored upside down to prevent condensation damaging the agar.

• In school labs, cultures should generally be incubated at a maximum of 25℃ to prevent growth of harmful microorganisms.

antiseptics destroy or inhibit the growth of microorganisms and prevents the growth of bacteria

Phagocytes engulf and digest pathogens

Lymphocytes release antibodies which attach to antigens on a pathogen/cell

neutralises toxic substances produced by the pathogen

in response to a second infection by the same pathogen

pathogen into the body to stimulate white blood cells to produce antibodies.

Antibiotics can’t kill viral pathogens and specific bacteria should be treated by specific antibiotics .

stunted growth as nitrate ions are needed for protein synthesis

discolouration as magnesium ions are needed to make chlorophyll

foxgloves

willow

Penicillium mould

toxicity, efficacy and dose

peer review to help prevent false claims.

more likely to suffer from infectious diseases

cancers

allergies such as skin rashes and asthma

depression and other mental illnesses

• Mouse lymphocytes stimulated to produce a specific antibody.

• Lymphocytes combined with a tumour cell to form hybridoma cells.

• Hybridoma cells both divide and make the antibody.

• Single hybridoma cells are cloned to produce many identical cells that all produce the same specific antibody.

• A large amount of the antibody can be collected and purified.

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

They are attached to the end of a pregnancy test stick onto which a woman urinates. If she is pregnant, HCG will be present in her urine and will bind to the monoclonal antibodies on the test stick. This will cause a change in colour or pattern which will indicate pregnancy.

To identify the presence of proteins or for purification of the target protein. When linked with fluorescent tags, monoclonal antibodies are used to analyse cell types in blood/tissue or for isolation of cells.

Cancerous cells have antigens on their surface. Monoclonal antibodies can be designed to bind specifically with these antigens. When injected into a person's body, the monoclonal antibodies will bind with these cancer cells and clump them together. This makes it easier to identify a cancerous tumour, which can then be treated or removed. The antibodies can be made slightly radioactive to allow the cancerous cells to be detected in the body, for example using a PET scanner.

Monoclonal antibodies have also been designed to treat cancer by:

Carrying drugs that have been attached to them, to the tumour. This means that the drugs specifically target the cancer cells and can allow smaller doses of chemotherapy drugs to be used. This can reduce the side effects and reduce risk to healthy cells.

Encouraging your immune system to attack the cancer cells directly.

Monoclonal antibodies can be produced to be able to target specific things in the blood, such as certain hormones, drugs and pathogens. Labs use them to run investigations about the levels of different substances in the blood so they can diagnose diseases and hormone imbalances and carry out drug tests.

Monoclonal antibodies can be made to bind to antigens on blood clots. The monoclonal antibodies can be attached to dyes that will glow fluorescently under UV light or attached to radioactive elements which can be detected with special cameras. This can make locating the clot much easier and can help to speed up how quickly a patient is treated.

interphase, mitosis and cytokinesis

Before a cell can divide it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria. The DNA replicates to form two copies of each chromosome.

One set of chromosomes is pulled to each end of the cell and the nucleus divides.

The cytoplasm and cell membrane divides to form two identical cells

differentiate into any type of plant cell, throughout the life of the plant.

• 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.

This leads to genetically identical offspring. Only mitosis is involved.

meiosis

they provide a trusted form of scientific communication and confirmation and make sure no mistakes have been made repeatedly

may be oversimplified, inaccurate or biased.