GCSE Biology

Communicable diseases

Infectious (can be transmitted)

Non-communicable disease

Can’t be transmitted

Microbe/Microorganism

very small organism

Pathogen

A disease causing organism

Types of pathgogen

virus bacteria fungi protists

How does bacteria and viruses cause illness

they divide rapidly and release harmful toxins or they invade the cells and reproduce in it causing the cell to burst and die

how can a pathogen spread

water contact water droplets in air

Size of bacteria

1-5 micro metres (µm)

1 micro metre = 0.001

Size of viruses

0.02-0.3 micro metres

Size of Fungi

50+ micro metres

Size of protists

1+ micro metres

How they cause disease bacteria

multiply rapidly and release toxins

How they cause disease Viruses

by invading and killing cells

How they cause disease Fungi

They stop plants from photosynthesising

How they cause disease Protists

bites of infected insects

Examples of bacteria

Salmonella

cholera

Gonorrhoea

Examples of viruses

flu

covid

HIV/AIDS

Examples of fungi

rose black spot, ringworm

Examples of protists

maleria

Plasmodium

protists that causes malaria

A parasite

an organism that lives on another organism and cause harm.

Vector

An organism that carries a pathogen to another organism

Physical barriers

Skin

Nose

Trachea

Stomach acid

Lymphocytes

produce antibodies/antitoxins

Phagocytes

engulf pathogens

Role of white blood cells

producing antitoxins, ingesting microbes (non-specific response), producing antibodies

how vaccines work

pathogen enters body

causes immune system to respond

microbe had been made harmless

Lymphocytes produce antibodies

White blood cells remember antibodies

if body attacked by pathogen again it can make antibodies faster.

detecting plant diseases

growths, malformed stems leaves roots, areas of decay, visible pests

Identifying plant diseases

dna analysis

compare symptoms

test kits

plant defences Physical

Physically stops pathogens form getting in

eg bark , waxy cuticle

plant defences Chemical

Chemicals that the plant can secrete

these can be used in medicine

plant defences Mechanical

Ways the plant defends its self from being eaten

hairy stems thorns leaves that drop when touched.

Difference between virus and bacteria

virus- nonliving cannot be treated by antibiotics no cell wall smaller

bacteria- can be affected by antibiotics dont need host to reproduce can live outside a host

How does bacteria reproduce

1 cell splits into 2

how do viruses reproduce

replicate itself 1000s of times

What causes symptoms of disease

its the bodies way of trying to get rid of the pathogen

life cycle of plasmodium

Mosquito sucks blood containing the protists and passes it on the other people when it sucks their blood.

why are antibodies specific to one pathogen

each pathogen has antigens with unique shape so antibodies need to fit the same shape.

herd imuntiy

when the majority of the population is immune to a disease so there are less people who can transmit it meaning less people who are not immune get sick

how do aphids affect pkant growth

aphids suck the sap of plants from the phloem affecting the growth rate and killing the,

measles symptoms

fever red rash

cause brain damage and blindness

hiv and aids symptoms

flu like symptoms

HIV attacks the immune system until they cant fight certain diseases such as cancer

TMV symptoms

Mosaic pattern of plants

virus destroys cells

Measles transmission

inhalation form coughs and sneezes

HIV and AIDS transmission

blood saliva std

TMV transmission

contact between plants

Salmonella transmission

raw eggs meat poultry

risk factors for cardiovascular diseases

smoking excessive drinking no exercise poor diet

photosynthisis equation

co2+water → glucose+o2

Lactic acid

makes muscles hurt is toxic, oxygen is used to get rid of it

AEROBIC 1

releases lots of energy, uses o2, produces co2 and h2o, long time, low intensity, C6H12O6+O2→CO2+H20,

ANAEROBIC

Releases less energy, short time, high intensity, glucose to lactic acid, happens in muscle cells

ALVIOLI ADAPTATIONS

THIN CELL WALLS, LARGE SURFACE AREA

OXYGEN DEBT

The amount of oxygen required to remove the lactic acid, and replace the body's reserves of oxygen

LIMITING FACTORS

A FACTOR THAT LIMITS PHOTOSYNTHESIS

PRODUCTS OF RESPIRATION

water and co2

What are enzymes

Enzymes are catalysts. They speed up useful chemical reactions in the body.

Enzymes need a specific pH and temperature to work. If they are not in this environment they will

denature. this means that the active site changes and it no longer fits the substrate

Starch is broken down into

sugars

Protiens is broken down into

amino acids

Lipids are broken down into

glycerol and fatty acids

Lipids is broken down by

Lipase

Proteins is broken down by

Protease

Starch is broken down by

Amylase

Where is bile produced

in the liver

where is bile stored

in the gallbladder

Where is bile released

in the small intestine

what does bile do

It neutralises the stomach acid acid emulsifies fats

Salivary glands

Produce amylase in saliva

Oesophagus

Muscle that transports food to stomach

Liver

Bile is produced here

Stomach

Pummels food

Produced protease

Produced hydrochloric acid-To kill bacteria and give right pH for protease

Gallbladder

Bile is stored

Pancreas

Makes Protease, amylase, lipase

Large intestine

excess water is absorbed

small intestine

digested food is absorbed into the blood

Test for sugars

Benedict’s test Positive-Blue to green to yellow to red

Test for starch

iodine Positive- Orange to black or blue

Test for Proteins

biuret Positive- Blue to purple

Test for lipids

Sudan 3 Positive- Red layer

Animal cell

Plant cell

magnification

image size/ real size

How to prepare slide

add drop of water to slide, cut onion, separate the layers epidermal tissue, place tissue into water, add drop of iodine, place cover slip,

Order of size

cell, tissue, organ, organ system, organism

Diffusion

is the spreading out of particles from an area of higher concentration to an area of lower concentration

Diffusion happens in

gasses and solutions

Osmosis

is the movement of water molecules across a semi permeable membrane from high to low concentration

Potato osmosis experiment

cut up potato into cylinders, measure mass of potatoes, put potatoes in varying sugar solutions, leave for 24 hours, measure mass, drawn water in by osmosis = bigger mass, water drawn out by osmosis = smaller mass, calculate percentage change.

percentage change

Final value - Original/ original x 100

Active transport

When substances are absorbed against the concentration gradient from low to high concentration

surface area to volume ratios

volume= length x width x height, area = length x width, put into ratio, simplify

how gills work

water enters fish through mouth, passes out through gills, o2 diffues from water into blood, co2 diffues from blood into water, each gill has gill filaments, have large surface area, lot of cappileries,

curculatory system

Heart

Arteires carry

blood away from the heart

Cappileries are involved

with the exchange of materials

Viens carry

blood to the heart

Arteries info

high pressure, walls are strong and elastic, thick walls,