Biology Revision

What is the function of the nucleus

Contains genetic material and controls cell activities

What structure controls what enters and leaves the cell

Cell membrane

What is the function of mitochondria

Site of aerobic respiration

What is the function of ribosomes

Protein synthesis

What structure strengthens plant cells

Cell wall

What structures are found in plant cells but not animal cells

Cell wall chloroplast permanent vacuole

What is cell differentiation

Process where cells become specialised

When does most cell differentiation occur in animals

Early development

Why are sperm cells specialised

Tail for movement and many mitochondria

Why are root hair cells specialised

Large surface area for water and mineral absorption

What is magnification

Image size divided by actual size

How do you calculate actual size

Image size divided by magnification

What unit is cell size usually measured in

Micrometres

What is diffusion

Movement of particles from high to low concentration

What factors affect diffusion rate

Temperature surface area concentration gradient

What is osmosis

Movement of water from high to low water potential through a partially permeable membrane

What happens to an animal cell in pure water

It bursts

What happens to a plant cell in pure water

It becomes turgid

What is active transport

Movement against a concentration gradient using energy

Give an example of active transport in humans

Glucose absorption in the small intestine

What is the role of enzymes

Speed up chemical reactions

What is the active site

Region where substrate binds

What happens when an enzyme denatures

Active site changes shape

Why does high temperature denature enzymes

Bonds break changing shape

Why does low temperature reduce enzyme activity

Fewer successful collisions

What does pH affect in enzymes

Shape of the active site

What required practical involves enzymes

Effect of pH on amylase

Why is a control used in experiments

To compare results

What is aerobic respiration

Release of energy from glucose using oxygen

What is the word equation for aerobic respiration

Glucose plus oxygen produces carbon dioxide and water

What is anaerobic respiration in muscles

Glucose produces lactic acid

Why is anaerobic respiration less efficient

Less energy released

What is oxygen debt

Oxygen needed to remove lactic acid

What is photosynthesis

Process plants use to make glucose

What is the word equation for photosynthesis

Carbon dioxide plus water produces glucose and oxygen

What factors limit photosynthesis

Light intensity carbon dioxide temperature

What happens when light is limiting

Increasing light increases rate

What is the role of chlorophyll

Absorbs light energy

What is the function of stomata

Gas exchange

What tissue transports water in plants

Xylem

What tissue transports sugars in plants

Phloem

What is transpiration

Loss of water vapour from leaves

What increases transpiration rate

Light wind temperature

Why do leaves have a large surface area

Maximise photosynthesis

What are arteries

Blood vessels carrying blood away from the heart

Why do arteries have thick walls

To withstand high pressure

What are veins

Blood vessels carrying blood to the heart

Why do veins have valves

Prevent backflow

What are capillaries

Tiny vessels for exchange

What do red blood cells transport

Oxygen

How are red blood cells adapted

Biconcave shape no nucleus haemoglobin

What is plasma

Liquid part of blood

What do platelets do

Help blood clot

What is coronary heart disease

Blocked coronary arteries

What causes coronary heart disease

Fatty deposits

How does smoking increase heart disease risk

Damages arteries and increases blood pressure

What is a pathogen

Disease causing organism

What types of pathogen exist

Bacteria viruses fungi protists

How do bacteria cause disease

Produce toxins or damage cells

How do viruses cause disease

Invade cells and reproduce

What causes measles

A virus

Why is measles dangerous

Can cause pneumonia or brain damage

What is a vaccine

Dead or inactive pathogen

How do vaccines work

Stimulate antibody production

What is an antibody

Protein that binds to antigens

What is immunity

Ability to resist disease

What is antibiotic resistance

Bacteria survive antibiotics

Why do antibiotics not work on viruses

Viruses reproduce inside cells

What is herd immunity

Reduced spread when most are immune

What is type 1 diabetes

Pancreas does not produce insulin

What is type 2 diabetes

Cells do not respond to insulin

What hormone lowers blood glucose

Insulin

What hormone raises blood glucose

Glucagon

What organ controls blood glucose

Pancreas

What is homeostasis

Maintaining stable internal conditions

What is negative feedback

Reverses a change

What organ regulates water balance

Kidneys

What is urea

Waste from protein breakdown

What happens in the kidneys

Filtration reabsorption excretion

What hormone controls water balance

ADH

What happens when ADH increases

More water reabsorbed

What system gives fast responses

Nervous system

What system gives slow long lasting responses

Endocrine system

What is a hormone

Chemical messenger in blood

What gland produces adrenaline

Adrenal glands

What does adrenaline do

Increases heart rate and breathing

What is a reflex action

Automatic response

Why are reflexes important

Prevent injury

What makes up the central nervous system

Brain and spinal cord

What is DNA

Genetic material

What is a gene

Section of DNA coding for a protein

What is a chromosome

Long DNA molecule

How many chromosomes are in human body cells

46

How many chromosomes are in gametes

23

What is mitosis

Cell division for growth and repair

What is meiosis

Cell division producing gametes

What is variation

Differences between individuals

What causes variation

Genes and environment

What is natural selection

Best adapted survive and reproduce

What is speciation

Formation of new species