Bio - Structure and Functions in living organisms

nucleus

contains DNA

cytoplasm

site of reactions

cell membrane

selectively permeable membrane

controls what goes in and out of cell

cell wall

provides structural support and maintains cell shape

mitochondria

site of aerobic respiration

prduces atp

chloroplasts

site of photosynthesis

light energy to chrmical

ribosomes

site of protein synthesis

vacuole

stores water, nutrients and waste

maintains pressure in plants

cell differenciation

process in which a cell changes to become specialised for its job

cells can develop different organelles and turn into different types of cells to allow them to carry out specific functions.

elements in carbohydrates

carbon

hydrogen

oxygen

elements in lipids

carbon

hydrogen

oxygen

elements in proteins

carbon

hydrogen

oxygen

nitrogen

what are carbohydrates made up of

starch and glycogen

what are lipids made up of

fatty acids and glycerol

what are proteins made up of

amino acids

enzymes

biological catalysts in metabolic reactions (useful to organism)

increases speed of reaction without being used up

photosynthesis equation

6CO2 + 6H2O → C6H12O6 + 6O2

how do light levels affect photosynthesis

chlorophyll uses light energy

if light intensity increases, rate increases steadily

then limiting factors temp and CO2 slow it down

how do CO2 levels affect photosynthesis

one of the raw materials

increasing concentration increases rate up to a point

then graph flattens out, showing that CO2 is no longer limiting factor

how does temp affect photosynthesis

affects enzymes

it increases with rate but up to a point

if temp too high, enzymes denature so rate rapidly decreases

structure of leaf

adaptations of a leaf

flat, broad leaves - larger SA:V

epidermis and mesophyll cell walls very thin - short diffusion distance

many stomata - a lot of entry and exit for gasses

air spaces - gasses can quickly reach places for photosynthesis and respiration

ability to open and close stomata - open when sunny and close to prevent water loss

why do plants need mineral ions

for growth

why are magnesium ions needed in plants

for chlorophyll

why are nitrate ions needed in plants

for amino acids

what does a balanced diet include

carbohydrates

proteins

lipids

vitamins

minerals

water

dietary fibre

why are carbohydrates needed in humans

glucose is used in respiration

(sugars)

why are proteins needed in humans

growth and repair of tissues

production of enzymes

antibodies

examples of proteins

meat / eggs / dairy / nuts + seeds

why are lipids needed in humans

concentrated energy source

part of cell membrane

examples of lipids

dairy / oils / nuts

why is vitamin A needed in humans

vision

immune system

healthy skin

(retinol)

why is vitamin C needed in humans

wound healing

immune system

prevent scurvy

why is vitamin D needed in humans

calcium absorption

why is calcium needed in humans

strong bones/teeth

why is iron needed in humans

needed to make haemoglobin for healthy blood

why do energy requirements vary in humans

due to activity levels, age and pregnancy

peristalsis

movement of food down the alimentary canal

circular muscles contract and make tube narrow

longitudinal muscles contract to make tube wide and short

human alimentary canal

mouth

salivary glands

oesophagus

stomach

small intestine (duodenum, ileum)

large intestine/colon

rectum

anus

what does the pancreas do

produces digestive enzymes to break down food

lipase, protease, amylase

breaking down of starch

starch → maltose → glucose

by amylase(produced in salivary glands and pancreas) then maltase(produced in small intestine)

breaking down of proteins and lipids

proteins → amino acids

by protease

lipids → fatty acids + glycerol

by lipase

bile production and storage

produced in liver and stored in gall bladder

role of bile

emulsifies fats/lipids (so that lipase can work more effectively)

neutralises stomach acids

adaptations of small intestine

very long allowing for sufficient time for complete digestion

folded inner surface to increase SA available for absorption

villi - millions of tiny projections on walls which dramatically increase SA and increase rate of absorption of nutrients

respiration

produces energy in living organisms

aerobic respiration equation

glucose + oxygen → carbon dioxide + water + ATP

C6H1206 + O2 → CO2 + H2O + ATP

anaerobic respiration equations

humans:

glucose → lactic acid + ATP

plants:

glucose → ethanol + CO2 + ATP

aerobic vs anaerobic respiration

requires oxygen - does not

occurs in mitochondria - in cytoplasm

complete breakdown of glucose - incomplete

efficient, much energy produced - small amount

slower - faster

— fermentation in plants + yeast

gas exchange in plants

CO2 required for photosynthesis (to make glucose) (waste product of respiration)

O2 required for respiration (to release energy from glucose) (waste product of photosynthesis)

respiration vs photosynthesis in day

light intensity high, stomata open so CO2 can enter for photosynthesis (hydrogen carbonate indicator is purple)

respiration vs photosynthesis in night

light intensity low, no photosynthesis, no CO2 entering, stomata closed (hydrogen carbonate indicator is yellow)

hydrogencarbonate indicator

yellow → orange → red → pink → purple

yellow: highest conc of CO2 (more respiration than photosynthesis)

purple: lowest conc of CO2 (more photosynthesis then respiration)

structure of thorax

ribs

intercostal muscles

diaphragm

trachea

bronchi

bronchioles

alveoli

pleural membranes

Breathing in

diaphragm contracts and moves downwards

volume of lungs increases and air is sucked in through the nose and mouth

intercostal muscles contract

ribs move up and out

breathing out

diaphragm releases and moves upwards

volume of lungs decreases and air is breathed out of nose and mouth

intercostal muscles relax

ribs move down and in

adaptations of alveloi

700 million alveoli with folded walls to increase SA

alveoli and capillary walls 1 cell thick for short diffusion distance

constant ventilation and good blood supply to maintain sleep concentration gradient

coronary heart disease

Nicotine increases blood pressure

this damages arteries

more fatty deposits into artery walls

blood more likely to clot

increased risk of heart attack and stroke

effects of smoking on respiratory system

carcinogens and tar can lead to uncontrolled cell division → tumours (lung cancer)

cilia damaged, can’t sweep mucus, dust and pathogens out, build up of mucus in air ways (smokers cough)

this can lead to infection and inflammation of bronchi (bronchitis)

smoke chemicals can cause walls of alveoli to break down and merge into larger, irregular spaces, significantly reduce SA for gas exchange (emphysema)