Organisation - P1

Cell Organisation and Enzymes:

  • Cell - a basic building block that all living organisms have

  • Tissue - a group of similar cells that work together

  • Organ - a group of different tissues that work together

  • Organ system - a group of organs working together

  • Organisms - organ systems working together

  • Enzymes catalyse (speed up) chemical reactions. Each enzyme only catalyses one specific reaction because of the unique shape of its active site.

  • Digestive enzymes break big molecules down into small soluble one. These can pass through the walls of the digestive system and be absorbed into the blood.

Digestion:

  • Amylase breaks down starch into maltose and other sugars. Produced in salivary glands, small intestine and pancreas

  • Protease breaks down protein into amino acids. Produced in stomach, small intestine and pancreas

  • Lipase breaks down lipids into glycerol and fatty acids. Produced in the small intestine and pancreas.

Lungs and Heart:

  • The lungs - trachea, lung, bronchus, alveoli (surrounded by capillary network)

  • Gas exchange - oxygen absorbed into the bloodstream from the lungs and carbon dioxide is removed from the blood into the lungs to be exhaled.

  • The circulatory system is made up of the heart, blood vessels and blood Humans have a double circulatory system:

  • Circuit 1 - heart (right ventricle) > ( de oxygenated) lungs >(oxygenated) heart

  • Circuit 2 - heart (left ventricle) > (oxygenated) rest of the body > (de oxygenated) heart

  • Coronary arteries supply the heart muscle with oxygenated blood

  • Pacemaker cells in the right atrium wall control the resting heart rate.

Blood vessels and Blood:

Types of blood vessels:

  1. Arteries carry blood away from heart

  2. Capillaries carry blood close to body cells to exchange substances

  3. Veins carry blood back to the heart

Blood components:

  • Red blood cells - carry oxygen around the body

  • White blood cells - defend against infection

  • Platelets - help blood to clot at a wound

Plasma - carries everything in the blood

Cardiovascular disease:

  • Cardiovascular disease - diseases of the heart or blood vessels

Treatments:

  • Statins - reduce the amount of cholesterol in the blood slowing down the formation of fatty deposits.

  • Stent - Keeps coronary arteries open for a long time

  • Heart transplant - can treat heart failure. Donor hearts work better than artificial ones

  • Artificial heart - can be used while waiting for a donor or while the heart is healing

  • Replacement heart valves - can treat severe valve damage

Health and Disease:

  • health - the state of physical and mental wellbeing

Things that affect health

  • diet

  • stress

  • life situation (e.g. access to healthcare)

Types of disease:

  • communicable - a disease that can be spread from person to person or between animals and people

  • non communicable - a disease that cannot be spread

Risk factors for diseases and cancer:

  • Risk factors - thins that are linked to an increase in the likelihood that a person will develop a certain disease in their lifetime

  • A lack of exercise - cardiovascular disease

  • obesity - linked to type 2 diabetes and cancer of the bowl,live,kidneys

  • drinking too much alcohol - liver disease and brain function

  • smoking - cardiovascular lung disease and lung cancer

  • exposure to carcinogens (ionising radiation)- can cause cancer

Cancer:

  • a normal cell changes

  • uncontrolled growth and division

  • tumour forms (of mass cells)

Types of tumours:

  • benign tumour - membrane (usually present) , other cells unaffected

malignant tumour (cancer) - healthy tissues invaded, tumour cell travel in blood, secondary tumours elsewhere in the body.

Plant cell organisation:

Plant cell tissues:

  1. Epidermal tissue - covered with a waxy cuticle in the leaf to reduce water loss

  2. palisade mesophyll - where most photosynthesis happens (lots of chloroplasts)

  3. spongy mesophyll - tissue has air spaces to allow diffusion of gases

  4. xylem - carries water in the transpiration stream

  5. phloem - transports organic nutrients

  6. meristem - found at the growing tips of shoots and roots. the cells can differentiate into many types of cell so the plant can grow

  7. guard cells - adapted for gas exchange and controlling water loss within the leaf

  8. stomata - when the plant is short of water or its dark

Xylem products:

  • hollow tubes made of dead cells

  • lignin for strength

  • water and mineral ions

Phloem prodcuts:

  • elongated living cells

  • small pores in end walls to let cell sap through

  • food substances (mainly sugars) are moved from leaves to rest of plant

Translocation - the process in which food is moved through the phloem tubes

Transpiration:

Transpiration - the loss of water from a plant

  • water evaporates and diffuses out of the plant which causes water to be drawn into the plant from the roots

Things that increase transpiration rate:

  • warm temps

  • high light intensity

  • good air flow

  • low humidity