Biology 2

Cells are building block for living organisms

Tissue= group of cells with similar structure/ function

Organs= aggregation of tissues for specific functions

Organs organised into organ system (work together to form organisms)

Digestive system(example of organ system) organs work together to digest & absorb food

-converts food into small soluble molecules to be absorbed into bloodstream

Enzymes= catalyst for chemical reaction according to shape of active site

-Protease= break down proteins into amino acids

-Lipase breaks down lipids(fats) into glycerol & fatty acids

-work according to temperature & pH changes

Bile made in liver & stored in gall bladder (alkaline neutralised hydrochloric acid)

Alkaline solutions & larger surface area increase rate of fat broken down into lipase

Heart= organ that pumps blood around the body in circulatory system

-resting heart rate based on cells in right atrium

-right ventricle pumps blood to the lungs (where gas exchange takes place)

-left ventricle pumps blood around the rest of the body

Blood vessels (types: arteries, veins, capillaries)

-aorta

-vena cava

-pulmonary vein

-coronary arteries

Blood is tissue

-contains palsma( where red blood cells, white blood cells & platlets suspended)

layers of fatty material build up inside coronary arteries (narrowing them)

-reduces the flow of blood= lack of oxygen to heart muscles

Stents used to keep arteries open

Statins used to reduce blood cholesterol levels through slowing down rate of fatty deposits

Valves faulty= valves don't open fully or develop a leak

-replaced by biological or mechanical valves

Heart failure= donor heart, heart and lungs transplanted

Artificial hearts used to keep patient alive during wait

Health= state of physical & mental well-being

Diseases are major cause of ill health as well as:

-diet

-stress

-life situations

Types of diseases may interact

-defects in immune system = likely to suffer infectious disease

-Viruses in cell= trigger cancer

-Immune reactions= triggers allergies(skin rashes & asthma)

-Severe physical ill health= depression & mental illnesses

Non-communicable disease can have an effect on everyone 

Risk factors affect the rate of a disease

-aspects of lifestyle

-substances in body & envrionment

Cardiovascular disease (diet, smoking & exercise)

Type 2 diabetes (Obesity)

Liver & Brain function (alcohol)

Lung disease & cancer (smoking)

Smoking and alcohol have an effect on unborn children

Cancer( carcinogens & ionising radiation)

Cancer is a result of changes in cell = uncontrollable growth & division

Benign tumours = growth of abnormal cells contained in one area

Malignant tumours (cancer)= invade neighbouring tissues & spread to different parts of body through blood (creates secondary tumour)

Lifestyle & genetics= risk factors

Plant tissues 

-epidermal tissue

-palisade mesophyll

-spongy mesophyll

-xylem and phloem

-meristem (growing in tips of roots & shoots)

Leaf= plant organ 

Guard cells surrounded by stomata

Temperature, humidity, air movement & light intensity affect rate of transpiration

Root, stem & leaves transport substances through plant

Root hair cells are adapted for efficient for uptake of water (osmosis) & mineral ions (active transport)

Xylem transport water & mineral ions from roots to stem & leaves

-made of hollow tubes (strengthened by lignin)

-adapted to transport water in transpiration stream

Stomata & guard cells control gas exchange & water loss

Phloem transports sugars from leaves to rest of the plant

-made of elongated cells (cell sap moves from one phloem to the other though pores)

-movement of food molecules= translocation