Y9 Biology

EVERYTHING expanded (no shortcuts) Full MRS GREN breakdown All cell structures + functions All processes in detail FULL nutrition (with deficiencies) EXTRA “trap” flashcards teachers love

What does MRS GREN stand for?

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition

Define movement (biology)

The ability of an organism to change position or move parts of its body

Define respiration

The chemical reactions in cells that break down glucose to release energy

Define sensitivity

The ability to detect and respond to stimuli in the environment

Define growth

Permanent increase in size and dry mass

Define reproduction

The process of producing offspring

Define excretion

The removal of metabolic waste products

Define nutrition

The intake of materials for energy, growth and development

What is homeostasis?

The regulation of internal conditions to maintain a stable environment

What is a cell?

The basic unit of life

Function of nucleus

Controls cell activities and contains genetic material (DNA)

Function of cytoplasm

Site of chemical reactions

Function of cell membrane

Controls movement of substances in and out

Function of mitochondria

Site of aerobic respiration

Function of ribosomes

Site of protein synthesis

What is a plant cell?

A eukaryotic cell with chloroplasts and a cell wall

Function of cell wall

Provides strength and support

What is the cell wall made of?

Cellulose

Function of chloroplast

Site of photosynthesis, contains chlorophyll

Function of vacuole

Contains cell sap and maintains turgor pressure

What is an animal cell?

A eukaryotic cell without cell wall or chloroplasts

Do animal cells have chloroplasts?

No

Do animal cells have a cell wall?

No

State 3 similarities between plant and animal cells

Nucleus, cytoplasm, cell membrane

State 3 differences between plant and animal cells

Plant: cell wall, chloroplasts, large vacuole; Animal: none of these

Define diffusion

Movement of particles from high to low concentration

Is diffusion active or passive?

Passive

Define osmosis

Diffusion of water across a partially permeable membrane

Direction of osmosis

From high water concentration to low water concentration

Define active transport

Movement of substances against concentration gradient using energy

Source of energy for active transport

Respiration (ATP)

Effect of temperature on diffusion

Increases rate

Effect of surface area on diffusion

Increases rate

Effect of distance on diffusion

Decreases rate when distance increases

Effect of concentration gradient on diffusion

Steeper gradient increases rate

Why are unicellular organisms efficient?

High surface area to volume ratio allows diffusion

Why do multicellular organisms need transport systems?

Diffusion is too slow over large distances

Structure of trachea

Tube supported by cartilage rings

Function of bronchi

Carry air into lungs

Function of bronchioles

Distribute air within lungs

Function of alveoli

Site of gas exchange

Adaptation: alveoli large surface area

Increases diffusion rate

Adaptation: thin walls

Short diffusion distance

Adaptation: good blood supply

Maintains concentration gradient

Adaptation: moist surface

Gases dissolve easily

What happens during inhalation?

Diaphragm contracts, ribs move up and out, volume increases

What happens during exhalation?

Diaphragm relaxes, ribs move down and in, volume decreases

What is an enzyme?

A biological catalyst that speeds up reactions

What is the active site?

The region where substrate binds

What is the lock and key model?

Substrate fits exactly into enzyme active site

What is denaturation?

Permanent change in enzyme shape

Effect of high temperature on enzymes

Denatures enzyme

Effect of low temperature on enzymes

Slows reaction

Effect of pH on enzymes

Extreme pH denatures enzyme

Test for starch

Iodine solution turns blue-black

Test for glucose

Benedict’s solution + heat turns brick-red

Test for protein

Biuret turns purple

Test for lipids

Ethanol emulsion test turns milky

What is a balanced diet?

A diet with correct proportions of nutrients

Function of carbohydrates

Provide energy

Sources of carbohydrates

Bread, rice, pasta

Deficiency of carbohydrates

Lack of energy

Function of proteins

Growth and repair

Sources of proteins

Meat, eggs, beans

Deficiency of protein

Kwashiorkor, poor growth

Function of lipids

Energy storage and insulation

Sources of lipids

Butter, oils

Deficiency of lipids

Weight loss, lack of energy

Function of vitamin A

Vision in low light

Source of vitamin A

Carrots, liver

Deficiency of vitamin A

Night blindness

Function of vitamin C

Healthy skin and gums

Source of vitamin C

Citrus fruits

Deficiency of vitamin C

Scurvy

Function of vitamin D

Calcium absorption for bones

Source of vitamin D

Sunlight, fish

Deficiency of vitamin D

Rickets

Function of calcium

Strong bones and teeth

Source of calcium

Dairy products