Human Biology - Unit 1 - ATAR

atp is used for..

• anabolic reactions

• cell division and growth

• movement of the whole cell

• active transport

cell wall

A rigid structure that surrounds the cell membrane and provides support to the cell

cytoplasm

- contents of the cell, not including the nucleus

cytosol

- fluid part of cytoplasm

cytoskeleton

- mechanical support, help move substances, anchor organelles

cilla + flagella

- provide mobility

- cilla: short external features

- flagella: sperm cells, whip-like extensions.

centrioles

- pairs of microtubular structures

- play role in cell division

membranous organelles

- functional components within cytoplasm

- bound by membranes

nucleus

- control center

- contains DNA and nucleolus

DNA

- hereditary material

- found as long strands called chromatin

- rods of wound up cells: chromosomes

nucleolus

- cells have 2/+

- forms ribosomes for cytoplasm

- direct synthesis of RNA

mitochondria

- site of aerobic respiration

- releases adenosine triphosphate (ATP/energy)

- breaks down glucose molecules

endoplasmic reticulum

- helps move substances within cells

- site of many chemical reactions

rough er

- have ribosomes attached to surface

- manufacture proteins

smooth er

- has enzymes to help build molecules

golgi apparatus

- modifies, packages, and sorts proteins for transport in and out of the cell

lysosomes

- contain digestive enzymes

- aid in cell removal

- digest invaders

- break down old cell parts

vacuoles

- membrane bound storage sacs

- contains food, water, waste

phospholipid bilayer

- structural framework of cell membrane

- semi-permeable

hydrophilic head

- head attracts water

- face outwards

hydrophobic tail

- tail repels water

- face inwards

carbohydrate chains

- allow for cell to cell communication

cholesterol

- embedded in membrane to help bind it together

protein channels

- provide easy access via channel into cell for a number of molecules

protein carriers

- embedded into layers to facilitate transport of different molecules in and out of cell

molecules can enter or exit cell by...

- using transport proteins

- dissolving directly through phospholipid bilayer

selectively permeable

- allows some substances to cross more easily than others

passive transport

- require no atp

- high to low conc

- along conc gradient

active transport

- requires atp

- low to high conc

- against conc gradient

- use transport proteins

hypotonic solution

- net water gain (moves in)

- cell swells (animal bursts)

- high conc outside, low inside

isotonic solution

- no net loss or gain

- equilibrium in and out

hypertonic solution

- net water loss (moves out of cell)

- cell shrinks

- high conc in, low conc out

simple diffusion

- movement of particles from region of high conc to region of low conc, along conc gradient

osmosis

- diffusion of water across semi-permeable membrane from low solute conc to high solute conc, along semi-permeable membrane

facilitated diffusion

- diffusion of molecules across cell membranes with assistance of transport proteins

exocytosis

- expulsion of particles from inside to out of cell using a vesicle

endocytosis

- surrounding and engulfing particles, from outside to inside of a cell using a vesicle

pinocytosis

- cell drinking

- engulfs liquid substance with cell membrane to form vesicle

- takes in fluids - nutrient uptake

- e.g. skin cells

phagocytosis

- cell eating

- engulfs solid substance with cell membrane to form vesicle

- nutrient uptake

- e.g. wbcs and viruses/bacteria

uses of carbohydrates

- atp for cellular resp

- stored in liver+muscle cells as glycogen

uses of lipids

- energy source and storage
- insulation
- protection of organs
- structural functions (myelin sheath, cell membrane)

uses of proteins

- metabolic functions (e.g. enzymes)

- oxygen transport (haemoglobin)

- protection (antibodies and blood clotting)

function of vitamins

- organic substance essential in small quantities for normal health

water soluble vitamins

B and C - easily excreted from body

fat soluble vitamins

A, D, E, K - absorbed in gut with help of lipids

metabolism

total of chem reactions that take place in our body

- anabolic

- catabolic

catabolic reactions

- complex substances broken down into simpler ones

- release energy

- e.g. cellular respiration

aerobic respiration equation

glucose + oxygen -> carbon dioxide + water

anabolic reactions

- build up complex molecules from simpler ones

- uses energy

- e.g. protein synthesis

biological uses of energy

- muscle contraction

- active transport

- cell division

- cellular movement

enzymes

- proteins that allow chemical reactions to occur at a normal body temp. by increasing rate of reaction

enzymes cause...

- increase reaction rate

- easier to react

activation energy

- energy needed to start a chemical reaction

(enzymes reduce activation energy needed)

lock and key model

- substrate binds to the active site of the substrate which are complementary to one another

factors effecting enzyme activity

- pH

- temperature

- concentration

- cofactors

- inhibitors

how does enzyme conc affect rate of reaction

- higher enzyme conc, faster rate of reaction

- higher substrate conc, faster rate of reaction until saturation point reached

how does temperature affect rate of reaction

- most enzymes work in limited range

- as temp increases, so does rate of reaction (increases movement of molecules)

- enzymes can become denatured/inactive if not right

how does pH affect rate of reaction

- altering can change shape of active site

- all enzymes have optimum pH where they work best

how does cofactors and coenzymes affect rate of reaction

- many enzymes need presence of certain ions

- changes shape of active site

- enzymes can't react without them

- many co-enzymes are vitamins

how does inhibitors affect rate of reaction

- substances that slow or stop enzyme activity

- used to control reactions

- e.g. many drugs

glycolysis

- 1st stage of anaerobic+aerobic resp.

- breaks down 1 molecule of glucose to 2 molecules of atp

- no atp needed

- in cytoplasm

Krebs Cycle (Citric Acid Cycle)

- pyruvate completely broken down into CO2

- needs O2

- in mitochondria

- releases atp

anaerobic respiration

- occurs in absence of oxygen

- 2 atp produced

- in cytoplasm

- no O2, pyruvic acid -> lactic acid

Why is anaerobic respiration important?

- during vigorous physical activity

- when resp and circ systems unable to supply muscle cells with enough O2 to keep up

lactic acid causes...

- accumulates in muscles and causes muscle pain and fatigue

- toxic to cell

energy cycle

- energy stored in 3rd phosphate so when removed, energy released

- when 3rd added, energy is stored

connective tissue`

holds everything together (e.g. blood cells), composed of cells and matrix

muscular tissue - skeletal

makes up muscles attached to bones, striated, voluntary, muscle to bone - movement by stimulus

cardiac muscle tissue

involuntary, makes up most of heart and contracts to pump blood, e.g. heart

nerve tissue

comprised of neurons, brain and spinal cord, transmits signals

vein

carries blood from body to heart - thin walls, with valves

valves

prevent backflow of blood

artery

carries blood away from heart to body, thick, muscular walls, high pressure

capillary

allows transfer of materials between blood and cells and vice versa, very thin walls of one cell

pericardium membrane

holds heart in place, prevents it from over stretching

right side of heart contains..

deoxygenated blood

left side of heart contains..

oxygenated blood

pulmonary vein

carries oxygenated blood from the lungs to the heart

pulmonary artery

carries deoxygentated blood from the heart to the lungs

aorta

carries oxygenated blood from left ventricle to the body

superior vena cava

deoxygenated blood from upper body to heart

inferior vena cava

deoxygenated blood from lower body to heart

plasma

transport of O2/CO2 (digested food, salts, heat, hormones, waste, etc.)

erthrocytes

• red blood cells

• most abundant cells in blood

• biconcave

• no nucleus

• produced in bone marrow

• transports oxygen

leucocytes

• white blood cells (inc lymphocytes, macrophages)

• fights infections

• produces antibodies

thrombocytes

• platelets

• involved in blood clotting

WBCs

fights infections + foreign substances by phagocytosis, contains nucleus, shape varies so can fit between cells in tissues, colourless, mobile

platelets

irregular shape to help blood clotting, round/oval, colourless, can't move on own

blood plasma

55% - consists of water, dissolved molecules, dissolved plasma proteins

granulocytes

ingests bacteria, in bone marrow

lymphocytes

produces antitoxins and antibodies, found in spleen, bone, and lymph nodes

role of lymphatic system

fluid balance (removes excess fluid and waste),

immune function (removes and destroys waste)

absorption of lipids (absorbs fat + vitamins and delivers nutrients)

lymph

remaining 10% of fluid left in tissues as clear/yellow fluid

arterioles

small arteries in tissue

lymphatic circulation

moves up to neck through lymph nodes, cleansed lymphs move up neck into circulatory system, bacteria trapped in fibres, macrophages destroy them

chambers of heart

left and right atrium, left and right ventricle

vena cavas

inferior = from lower body

superior = from upper body

types of valves

semi-lunar, bicuspid and tricuspid

CO2 transport in blood

8% dissolves in plasma as solution, 22% carbaminohaemoglobbin, in plasma bicarbonate ions as bicarbonate ions (HCO3-) and H+ ions, reacts with water to make carbonic acid (H2CO3) which breaks down ions 70%

oxygen transport in blood

3% dissolves in plasma as solution, 97% oxyhaemoglobin