Human Bio unit 1

phospholipid molecule

phosphate head (hydrophilic) and fatty acid tails (hydrophobic)

cell membrane made out of

phospholipid bilayer and associated proteins

functions of cell membrane

physical barrier, regulates passage of materials, sensitive to change, supports the cell

differentially permeable

allow certain molecules to pass through but restrict others

integral proteins of cell membrane

channel protein and carrier protein

processes of cellular transport

simple diffusion, facilitated transport, vesicular transport

simple diffusion

oxygen and carbon dioxide diffuse through bilayer following concentration gradient, passive process

osmosis

diffusion of water to balance the concentration of another substance

facilitated transport

transport by proteins in cell membrane by passive or active transport

protein channels

provide a pathway for small water-soluble molecules to travel through to avoid hydrophobic tails (passive transport)

characteristics of carrier-medicated transport

are specific- will only bind to a particular molecule, can become saturated, regulated by hormones

carrier-mediated facilitated diffusion

along concentration gradient (passive process)

carrier proteins process

only open on one side of membrane at a time, when molecule attaches it will change shape and open on other side

active transport via carrier proteins

transported against concentration gradient (uses energy in form of ATP)

vesicular transport

movement of substances across cell membrane in membranous sacs called vesicles (active process)

endocytosis process

taking liquids or solids into the cell by vesicular transport. cell membrane folds around particle, vesicle pinches off and suspended in cytoplasm

pinocytosis

taking liquids in by endocytosis

phagocytosis

taking solid particles in by endocytosis

exocytosis process

contents of vesicle inside cell pushed out. vesicle fuses with cell membrane and contents pushed into extracellular fluid

cytoplasm

thick fluid (cytosol) with organelles suspended in it

centrioles

cylindrical structures involved in cell division

endoplasmic reticulum (ER)

pairs of parallel membranes. provides a surface where chemical reactions can occur. channels between used for storage/transport

types of endoplasmic reticulum

rough ER (ribosomes attached), smooth ER (no ribosomes attached)

ribosomes

site of protein synthesis- joins amino acids to make proteins

cytoskeleton

consists of microfilaments and microtubules, gives shape and assists movement

lysosomes

break down materials taken into cell

nucleus

contains DNA. has nuclear membrane (double layers), which has nuclear pores- allow large molecules to pass through

nucleolus

composed of RNA

mitochondria

has double membrane (outer and folded inner), site of cellular respiration to produce energy for the cell

golgi body

modify and package proteins in vesicles for secretion from the cell

cell membrane

outer boundary of cell

vesicle

membrane-bound sac that transports materials in/out/within cell

epithelial tissue

lining tissue, cells are very close together

connective tissue

provides support and holds body parts together, cells are separated by non-cellular matrix

muscular tissue

cells (muscle fibres) are long and can contract

nervous tissue

made up of nerve cells called neurons

validity

extent to which an experiments tests what it is supposed to test

reliability

how similar the results of multiple trials are

accuracy

how correct the measurements are

human error

error due to limitations of human ability

random error

error due to limits in precision of measurements

systematic error

error due to way experiment was designed

metabolism

chemical reactions taken place in cells

catabolism

large molecules broken down to smaller ones (digestion)

anabolism

small molecules built up to larger ones (protein synthesis)

nutrients + types

substance in food used for growth, repair and maintaining body. water, carbohydrates, lipids, proteins, minerals, vitamins

nutrients- organic compound

have a carbon chain: carbohydrates, polysaccharides, lipids, proteins

nutrients- inorganic compound

do not contain carbon chain: water, minerals, vitamins

lock and key model

enzyme (key) is always complementary to shape of substate (lock)

enzyme

organic catalyst (made of proteins) increases reaction rate without being altered or destroyed

factors affecting enzyme activity

concentration of enzyme + substrate, products of reaction being removed, temperature (30-40), pH sensitive

enzyme cofactors

change shape of active site so it can combine with enzyme

enzyme inhibitors

slow or stop enzyme activity

cellular respiration equation

glucose + oxygen = carbon dioxide + water + energy (ATP and heat)

cellular respiration

chemical process that provides energy for cell

glycolysis

first phase of breakdown of glucose, does not need oxygen, occurs in cytoplasm, produces 2 ATP and 2 pyruvate

anaerobic respiration

no oxygen available, occurs in cytosol, no ATP produced

process of anaerobic respiration

pyruvate converted to lactic acid, accumulation in muscles may cause pain. lactic acid taken by blood to liver, recombine with oxygen to form glucose, then glycogen

oxygen debt

from anaerobic respiration, the extra oxygen needed after vigorous exercise (recovery oxygen)

aerobic respiration

breakdown of glucose to carbon dioxide and water in presence of oxygen, occurs in mitochondria, produces up to 38 ATP per glucose molecule

stages of aerobic respiration

pyruvate enters mitochondria, citric acid cycle, electron transport system

aerobic stage- pyruvate enters mitochondria

pyruvate converted to acetyl CoA, no ATP produced

aerobic stage- citric acid cycle

for every acetyl CoA that enters cycle, one ATP produced- 2 ATP produced per glucose

aerobic stage- electron transport system

uses oxygen. electrons passed between molecules, oxygen forms water. produces 34 ATP

uses of energy in cell

building molecules, cell division + growth, movement of cell + organelles, active transport

nasal cavity

warm + humidifies air, lined by mucous membranes + hair, that trap debris

structures of respiratory system

nasal cavity, pharynx, epiglottis, larynx, trachea, bronchi, bronchioles, alveoli

epiglottis

flap of tissue; covers oesophagus when inhaling, covers trachea when swallowing

trachea

made of C-shaped cartilage, epithelial lining produces mucus to trap dust + debris, cilia on lining move in waves to push it up to be swallowed/coughed

bronchi

primary, secondary, tertiary; C-shaped cartilage, gets smaller- smooth muscle + elastin, cilia + mucus trap and remove debris

bronchioles

smooth muscle + elastin- can expand when more oxygen needed, cilia + mucus trap and remove debris

alveoli

air sacs, the functional units of the lungs

inspiration process

decreasing pressure in lungs by increasing volume; diaphragm + intercostal muscles contract, rib cage moves upwards + outwards, lungs expands with expanding chest cavity

expiration process

diaphragm and intercostal muscles relax, diaphragm pushes up into chest cavity, rib cage moves downwards. air pressure greater in lungs than outside, air flows out until equalised

structure of lungs suited to gas exchange

large surface area of alveoli, surrounded by capillary network, membrane one cell wall thick. lungs positioned deep to prevent fluid evaporation, lung volume can be changed

emphysema

irritating particles cause damage to alveoli; lose elasticity, replaced with fibrous tissue, reduced surface area

lung cancer

irritate mucous membranes of air passages, more production of mucus, cannot be removed, trapped mucus ruptures alveoli- is emphysema

asthma

during attack, bronchioles constrict, secretion of excessive mucus, air flow is reduced

what blood is composed of

plasma (55%), formed elements (45%)

erythrocytes

red blood cells, biconcave shape, no nucleus, transport oxygen, 40-45% of blood (haematocrit number)

leucocytes

white blood cells, protect body from infections

thrombocytes

platelets, help in blood clotting

plasma

water and dissolved substances. transport components of blood: nutrients, wastes, hormones, proteins, antibodies

transport of oxygen

3% in suspended in plasma. 97% combines with haemoglobin on erythrocytes to become oxyhaemoglobin

transport of carbon dioxide

little amount is suspended in plasma, some combines with haemoglobin to become carbaminohaemoglobin, most carried in plasma as bicarbonate ions

transport of nutrients + waste

dissolved in plasma

blood clotting stages

vasoconstriction, platelet plug, coagulation

blood clotting- vasoconstriction

injured arteries constrict to reduce blood flow and blood loss

blood clotting- platelet plug

platelets stick to rough surface of damaged vessel, attract others + forms plug. plug reduces blood loss + release vasoconstrictors (enhance + prolong constriction)

blood clotting- coagulation

serious injuries. clotting factors in plasma produce fibrin. fibrin forms mesh that traps blood cells, platelets + plasma- forms clot

arteries

carry blood away from heart. contain thick smooth muscle + elastic fibres (can stretch to accommodate extra blood flow). muscle can contract to reduce blood flow to organ (vasoconstriction), or relax to increase (vasodilation)

types of blood vessels

arteries, capillaries, veins

veins

carry blood towards heart. thin wall. low pressure, requires valves

systole

period when heart muscle contracts, pumping phase

diastole

period when heart muscle relaxes, filling phase

atrial systole

contraction of atria forces blood to ventricles

ventricular systole

atria relaxes + refills. ventricles contract, force blood to arteries

lymphatic system functions

collect + return fluid that escapes from capillaries after being forced out due to high pressure. fighting infections

features of lymphatic system

one-way system, moves lymph through vessels by smooth muscle, skeletal muscle + valves

lymph node

acts as filters, contain white blood cells to fight infections