iGCSE biology ALL

everything for igcse biology!

Name organelles in animal cell

Cell membrane, cytoplasm, mitochondria, nucleus

Name organelles in a plant cell.

Permanent vacuole, cell membrane, cell wall, mitochondria, chloroplasts which are full of chlorophyll, cytoplasm, nucleus

What is their role of the nucleus?

Controls the activity of the cells

What is the role of the cell membrane?

controls what goes in and out of the cell

What is the role of mitochondria?

respiration

What is the role of the cell wall?

structure

What is the role of cytoplasm?

chemical reactions

What is the role of chloroplasts?

photosynthesis

What is an enzyme?

Biological catalyst which speeds up a reaction without being used up itself

What can energy be used for?

muscle cells to produce movement

active transport of ions and minerals,

building large molecules such as proteins

cell division

What is the word and symbol equation for aerobic respiration?

Glucose + Oxygen --> Carbon Dioxide + Water

C6H12O6 + 6O2 --> 6CO2 + 6H2O

What is anaerobic respiration?

respiration without oxygen

Anaerobic respiration word equation (yeast & plants)

Glucose --> Ethanol + Carbon Dioxide

Anaerobic respiration work equation (animals)

Glucose --> Lactic acid

What is oxygen debt?

The volume of oxygen needed to completely oxidize the lactic acid that builds up in the body during anaerobic respiration

Define diffusion

Movement of molecules from a high to low concentration

What can speed up the rate of diffusion?

Larger concentration gradient

Higher temperature

Decreased distance

Surface area increased

Describe the term 'active transport'

Movement of molecules from low to high concentration

Using energy (ATP)

Describe the term 'osmosis'

Diffusion of water molecules

from high water potential to a low water potential

through a partially permeable membrane.

Name some specialised cells?

1. Nerve cell (neurone)

2. Villi cell

3. Xylem vessel from the plant stem

4. Guard cells from surface of a leaf

5. Leaf palisade cell

6. Sperm cell / egg cell

7. Cilia cell

8. Red blood cell

What does xylem transport?

Water and mineral ions

How is a leaf palisade cell specialised?

It is full of chloroplasts for photosynthesis

How is a sperm cell specialised?

It has a tail for swimming and its head contains genes from the father

What is a tissue?

Cells grouped together which have a similar function

What is an organ?

A collection of several tissues carrying out a particular function

Name three organs

Heart, lungs, stomach, intestine, ovaries +testes, bladder, liver, pancreas, skin, kidneys, trachea, oesophagus and brain

What is an organ system?

Several different organs working together

Name an organ systems in the human body

Digestive, respiratory, circulatory, endocrine, directory, nervous, reproductive

What is the circulatory system?

Includes the heart and blood vessels which transport materials around the body

What is the nervous system?

Consists of the brain, spinal chord and nerves which coordinate the body's actions

What is the endocrine system?

Include glands which secrete hormones that act as chemical messengers

Name organelles in fungi

A cell wall made of Chitin, cell membrane, cytoplasm, vacuole and nucleus

Is yeast unicellular or multicellular?

Unicellular

What are hyphae?

Thread like filaments (fungi)

What is a mycelium?

A network of hyphae (fungi)

What is saprotrophic nutrition?

Digestion using enzymes that takes place outside of the organism

What are extracellular enzymes?

Enzymes that are secreted out of cells

What are protoctists?

They are a mixed group of organisms that don't fit into the plants, animals or fungi and most are single-celled microscopic organisms.

What are the protoctists called that have chloroplasts and carry out photosynthesis?

Algae

What does a bacteria cell consist of?

Circular DNA, cell wall, cell membrane, flagellum, plasmids, capsule (slime layer)

What is the purpose of the slime capsule?

Gives the bacterium extra protection

What is the purpose of the flagellum?

Movement

What are plasmids?

Small circular rings of DNA

What are pathogens?

An microorganism which causes disease

How do virus cells reproduce?

They can only reproduce inside other living cells (the host cell) by taking over their genetics to make more virus particles.

What joins ribs together?

Intercostal muscles

What is the purpose of the diaphragm?

It separates the contents of the thorax from the abdomen

What is the purpose of the cartilage in the trachea?

They support the airway and keep them open when we breathe in. Without the the trachea would squash flat when you breathe in

Which cells line the trachea?

Cilia and mucus cells

What happens to your thorax when you inhale?

• Ribs go up

• Intercoastal muscles contract

• Diaphragm flattens

• Volume increases

• Pressure decreases

• Air moves in

What happens to your thorax when you exhale?

• Ribs go down

• Intercoastal muscles relax

• Diaphragm relaxes (curves)

• Volume decreases

• Pressure increases

• Air moves out

Where does gas exchange happen in the lungs?

alveoli

How are alveoli adapted to be good at diffusion?

Large surface area

Thin cell wall - less distance

Lots of capillaries - maintains a constant concentration gradient

Why does breathing rate need to rise during exercise?

Muscles need more oxygen when working as they require more energy which they will get from respiring

What are 4 ways in which smoking can affect your lungs?

Bronchitis

Emphysema

Lung Cancer

Intake of carbon monoxide

How does Emphysema affect your lungs?

Alveoli fuse together and surface area decreases - gas exchange decreases

What are the 7 key elements of a balanced diet?

Carbohydrates, lipids, protein, mineral, vitamins, water and fibre

What is the importance of carbohydrates?

Respiration and long term store of energy

Where is lactose found?

In milk

Where is sucrose found?

Plants

What is starch?

Starch is a complex carbohydrate which is an insoluble molecule.

What is glycogen?

Complex carbohydrate in animals (long term store)

What is cellulose?

Complex carbohydrate in plants (long term store) - plant cell walls made of it

What are the three elements that make up lipids?

Hydrogen, carbon and oxygen

What are lipids made of?

Glycerol joined to three fatty acids.

What is the role of fat in the body?

Insulation, energy store, protection,

Why do we need protein?

Growth and repair of tissues. Many compounds in the body are made from protein, including enzymes, hormones, antibodies

What do proteins consist of?

Many amino acids