Cambridge IGCSE Biology Chapters 1–4 Revision flashcards

What does MRS GREN stand for?

Movement Respiration Sensitivity Growth Reproduction Excretion and Nutrition

What is movement?

An action by an organism or part of an organism that changes position

What is respiration?

The chemical reactions in cells that break down nutrient molecules and release energy

What is sensitivity?

The ability to detect and respond to changes in the environment

What is growth?

A permanent increase in size and dry mass

What is reproduction?

The processes that make more individuals of the same species

What is excretion?

The removal of toxic materials and substances in excess of requirements

What is nutrition?

Taking in materials for energy and growth

What are the five kingdoms?

Animals Plants Fungi Prokaryotes and Protoctists

What are the characteristics of animals?

Multicellular organisms that feed on other organisms and have no cell walls

What are the characteristics of plants?

Multicellular organisms that photosynthesise and have cellulose cell walls

What are the characteristics of fungi?

Organisms with chitin cell walls that feed by saprotrophic nutrition

What are prokaryotes?

Single-celled organisms without a nucleus

What are protoctists?

Mostly single-celled organisms with a nucleus

What is a vertebrate?

An animal with a backbone

What are the five vertebrate groups?

Mammals Birds Reptiles Amphibians and Fish

What are the characteristics of mammals?

Hair or fur and females produce milk

What are the characteristics of birds?

Feathers beaks and wings

What are the characteristics of reptiles?

Dry scaly skin and lungs

What are the characteristics of amphibians?

Moist skin and usually a life cycle involving water

What are the characteristics of fish?

Gills fins and scales

What are the main arthropod groups?

Insects Arachnids Crustaceans and Myriapods

How many legs do insects have?

Six

How many legs do arachnids have?

Eight

How many legs do crustaceans usually have?

Ten or more

What is a species?

A group of organisms that can reproduce to produce fertile offspring

What is binomial nomenclature?

The two-part scientific naming system using genus and species

What is a genus?

A group of closely related species

What is evolution?

The change in inherited characteristics of populations over generations

What is a dichotomous key?

A tool that identifies organisms using pairs of contrasting statements

What is DNA?

The molecule that carries genetic information

What is a cell?

The basic structural and functional unit of life

What does the nucleus do?

Controls cell activities and contains genetic material

What does the cytoplasm do?

Where most chemical reactions take place

What does the cell membrane do?

Controls movement of substances into and out of the cell

What do mitochondria do?

They are the site of aerobic respiration

What do ribosomes do?

They are the site of protein synthesis

What is the function of a cell wall?

It supports and strengthens the plant cell

What is the plant cell wall made of?

Cellulose

What is the function of a chloroplast?

It absorbs light for photosynthesis

What is chlorophyll?

The green pigment that absorbs light energy

What does the permanent vacuole contain?

Cell sap

What is a prokaryotic cell?

A cell without a nucleus

Where is bacterial DNA found?

In the cytoplasm

What is a plasmid?

A small circular piece of bacterial DNA

What is a root hair cell adapted for?

Absorbing water and mineral ions

What is a red blood cell adapted for?

Transporting oxygen

What is a sperm cell adapted for?

Swimming to and fertilising an egg

What is the function of cilia?

Moving substances across cell surfaces

What is a palisade cell adapted for?

Photosynthesis

What is the function of a neurone?

Transmitting electrical impulses

What is a tissue?

A group of similar cells working together

What is an organ?

A structure made of different tissues working together

What is an organ system?

A group of organs working together

What is an organism?

A living individual

What is the magnification formula?

Magnification = image size ÷ actual size

How do you calculate actual size?

Actual size = image size ÷ magnification

How do you calculate image size?

Image size = actual size × magnification

How many millimetres are in one metre?

1000

How many micrometres are in one millimetre?

1000

How many micrometres are in one metre?

1 000 000

What is diffusion?

The net movement of particles from higher to lower concentration

What is osmosis?

The net movement of water molecules through a partially permeable membrane from higher to lower water potential

What is active transport?

The movement of particles against a concentration gradient using energy

What is a concentration gradient?

A difference in concentration between two areas

What is a partially permeable membrane?

A membrane that allows some substances through but not others

Which process requires energy?

Active transport

Which processes are passive?

Diffusion and osmosis

What energy source is used in active transport?

Energy released by respiration

What happens to diffusion when temperature increases?

Particles move faster and diffusion becomes faster

What happens to diffusion when surface area increases?

Diffusion becomes faster

What happens to diffusion when the concentration gradient increases?

Diffusion becomes faster

How does diffusion help gas exchange?

Oxygen and carbon dioxide move down their concentration gradients

How do root hair cells absorb mineral ions?

By active transport when necessary

What happens to a plant cell in a dilute solution?

Water enters and the cell becomes turgid

What happens to a plant cell in a concentrated solution?

Water leaves and the cell may become plasmolysed

What happens to an animal cell in a dilute solution?

Water enters and the cell may burst

What happens to an animal cell in a concentrated solution?

Water leaves and the cell shrinks

What does turgid mean?

Firm and swollen due to water entering the cell

What does flaccid mean?

Limp because the cell has lost some water

What does plasmolysed mean?

The cell membrane pulls away from the cell wall after water loss

How do you calculate magnification?

Image size ÷ actual size

How do you calculate actual size?

Image size ÷ magnification

How do you calculate image size?

Actual size × magnification

How do you calculate percentage?

Part ÷ whole × 100

How do you calculate concentration?

Mass of solute ÷ volume of solution

How do you convert cm³ to dm³?

Divide by 1000

How do you convert dm³ to cm³?

Multiply by 1000