Biology all Y9 Notes & Flashcards [end of years revision]

Cells & pathogens, Biomolecules, Cellular respiration & Transport, Alveoli in lungs

Magnification

how much bigger than real life an image is

worked out with a microscope by multiplying the two lenses together

Resolution

smallest distance between two points where they can still be seen as separate

Field of view

circular area in a microscope’s view

Scale bars

on the sides of images, used to estimate sizes

Magnification equation

image / actual

Electron microscope

type of microscope that uses beams of electrons as a source of illumination and is much more powerful than a light microscope

How many millimetres (mm) in a metre?

1,000

How many micrometers (μm) in a metre?

1,000,000

How many nanometers (nm) in a meter?

1,000,000,000

How many picometers (pm) in a meter?

1,000,000,000,000

Eukaryotic cell

a cell with a nucleus

Cell membrane

thin bag, controls what enters/leaves

Cytoplasm

watery jelly, where cell’s activities occur

Mitochondria

where aerobic respiration occurs

Nucleus

controls cell, contains chromosomes & DNA

Ribosome

makes new protiens

Cell wall

(plant cell only) supports the cell, made of cellulose

Chloroplast

contains chlorophyll, used for photosynthesis

Vacuole

stores cell sap that keeps cell firm and rigid

Specialised cells

cells that have a function - their sub-cellular structures have adapted to their function

Specialised cells for digestion

have membranes with tiny folds (microvilli) which increase the surface area, allowing for faster absorption

Specialised cells for reproduction (sperm cells)

• streamlined shape

• lots of mitochondria for energy

• tail for swimming

• acrosome (helps them burrow into the egg cell)

• only one set of chromosomes

Specialised cells for reproduction (egg cells)

• nutrients in cytoplasm

• changes to cell membrane after fertilisation to stop more sperms coming in

• only one set of chromosomes

Diploid cells

cells with two sets of chromosomes

Haploid cells

cells with one set of chromosomes

Flagellum

spins round to move a cell (bacteria)

What do bacteria not have that other cells do?

nucleus, chromosomes, mitochondria, chloroplasts

What do bacteria have in place of things like the nucleus?

chromosomal DNA - controls cell’s activities

Slime coat (on bacteria)

for protection (not on all bacteria)

Flexible cell wall (on bacteria)

for support (not made of cellulose)

Plasmid & chromosomal DNA (in bacteria)

controls the cell’s activities in place of the nucleus

Pathogens

disease causing organisms. they produce toxins that damage cells, or invade them and change their functions

Why aren’t viruses true organisms

they don’t have a cellular structure

How do viruses cause disease

they infect a cell and take over its DNA & processes to make new viruses

Oral route

when a pathogen enters the body through the mouth

Capsids

strands of genetic material with a protein coat

Lysis

complete breakdown of a cell

Lytic cycle definition

life cycle of a virus that causes lysis

Lysogenic cycle definition

life cycle of a virus that inserts genetic material into a cell

Lytic cycle steps

1. virus attaches to cell & inserts genetic material

2. new genetic material & proteins created and assembled

3. cell lyses, releasing viruses

4. repeat

Lysogenic cycle steps

1. genetic material of virus inserts into chromosome

2. bacteria reproduces, replicating virus material too

3. virus material separates from chromosome

4. repeat

This doesn’t cause lysis

Test for starch

Iodine, turns blue-black for positive

Test for reducing sugar

benedict’s, red for positive, orange/yellow/green for less

Test for protein

biuret, purple for positive, lighter for less

Test for lipids (aka fats)

ethanol (emulsion test), cloudy/milky for positive

Health

a state of complete physical, mental and social well being and not just the absence of disease

Symptoms

things that give you cues as to which cells/organs are infected

Treatments

things that target diseased cells to try to help them get better

Non-communicable diseases

diseases that can’t be spread from one person to another e.g. heart attacks

Communicable diseases

diseases that are caused by pathogens

Four groups of pathogens

viruses, bacteria, fungi, protists

Cell

The smallest unit of life, carry out all life processes, all organisms are made of them

Cholera

Bacteria

Causes diarrhoea

Spread through water

Prevent by washing hands, cooking food, drinking clean water

Tuberculosis

Bacteria

Causes lung damage

Spread in air

Prevented by wearing masks, having good ventalation

Chalara ash dieback

Fungus

Causes leaf loss, bark lesions

Spread in air

Prevented by destroying plants

Malaria

Virus

Causes damage to blood and liver

Spread through animal vectors

Prevented with insect repellent

HIV

Virus

Causes destroyed white blood cells, leading to weakened immune system and onset of AIDS

Spread from body fluids

Prevented by having safe sex, getting tested

Helicobacter Pylori

Virus

Causes stomach ulcers

Spread through oral transmission

Prevented by cooking food

Ebola

Virus

Causes haemorrhagic fever

Spread from body fluids

Prevented by not touching bodies and isolated

Chlamydia

Bacteria

Causes pain while peeing, unusual discharge

Spread through unprotected sex

Prevented by getting tested & treated

Monomer

building block of a substance

Monomer of carbohydrates

Sugars

Monomer of lipids (fats)

fatty acids & glycerol

Monomer of proteins

amino acids

Function of carbohydrates

energy

Function of lipids (fats)

insulation, energy, cell membranes

Function of proteins

muscles, immune systems, enzymes

Enzymes

things that speed up processes without being used up

Denature

when a protein changes shape from extreme temp/pH and can’t work

Active site

where the enzyme and substrate join together

Specificity

one type of enzyme for one type of substrate

Product

the result(s) of the reaction

Enzyme-substrate complex

structure formed when enzyme and substrate come together

Catalyst

something that speeds up a reaction without being used up (e.g. an enzyme)

Catalyses

speeds up

Substrate that amylase breaks down

starch

Enzyme that is broken down by starch

amylase

Substrate that lipase breaks down

lipids

Enzyme that is broken down by lipids

lipase

Substrate that protease breaks down

protein

Enzyme that is broken down by protein

protease

Ending of all names of enzymes

ase

Optimum

the temp/pH where the enzyme is working the best/most

How enzymes work

1. The substrate binds to the enzyme forming an enzyme-substrate complex

2. Stress is placed on the bonds in the substrate and they break

3. Products are released and the enzyme can bind other substances

Rate of reaction definition

relative speed at which reaction takes place

Units of rate

s^-1

What goes on the y axis of a rate graph

rate

What goes on the x axis of a graph

what you’re changing e.g. temperature

Dependent variable

what you measure, on the y axis

Independent variable

what you change, on x axis

What binds with A

T

What binds with D

G

What do you need in a nucleotide

base, sugar, phospahte

Name of the shape DNA

double helix

Gene

section of a DNA molecule

Genome

Name for all genes in a cell

Where in the cell’s DNA found

in the nucleus

Extracting DNA practical

1. Break the cells open to get to the DNA (by mashing it)

2. Filter the debris e.g. the cell walls out and collect the nuclei

3. Add soapy water to dissolve the cell membranes and the nuclear membrane, which are made of lipids

4. Use ice cold ethanol to extract the DNA, you will get some slimy stuff which is the DNA

Cellular respiration

A series of chemical reactions that take place continually in all cells. Glucose is broken down releasing energy. It is an exothermic reaction so the heat produced keeps animals warm.

ATP

short term storage molecule for metabolism