Cells, Tissues, and Organs

Question 1

What can cells only be seen with?

Answer 1

A microscope

Question 2

What are the different types of microscopes and where are they used?

Answer 2

Light microscopes are used in schools

Electron microscopes are much more powerful. They can magnify things thousands of times more. They are used in research and industry

Question 3

What structures do most cells have in common?

Answer 3

• Nucleus - controls cell
• Cytoplasm - where chemical reactions take place
• Cell membrane - controls the movement of materials in/out
• Mitocondria - the powerhouse! Energy is released here due to aerobic respiration
• Ribosomes - where protein synthesis takes place

Question 4

What is an algal cell?

Answer 4

The cell of algae, single celled, or simple multicellular organisms that can photosynthesis but are not plants

Question 5

What do plant and algal cells also have in common?

Answer 5

• Rigid cell wall made of cellulose for support
• Chloroplasts containing chlorophyll for photosynthesis
• Permanent vacuole containing cell sap

Question 6

What is yeast?

Answer 6

A single-celled organism

Question 7

Draw and label a diagram of a yeast cell

Answer 7

Question 8

Draw and label a diagram of a bacterium cell

Answer 8

Bacteria are enclosed in a slime capsule

Question 9

When can bacteria be seen with the naked eye?

Answer 9

When they have multiplied to form colonies

Question 10

What happens as a cell matures?

Answer 10

It specialises/develops into a particular type of cell that performs a specific function

This is called differentiation (when cells differentiate)

Question 11

Give some examples of how the structure of a cell is linked to its function

Answer 11

• Lots of mitocondria - needs lots of energy (e.g. muscle, sperm)
• Lots of ribosomes - makes lots of proteins (e.g. gland cells which produce enzymes)
• Tails/flagella - needs to move (e.g. sperm)
• Receptor cells have special structures allowing them to detect stimuli (e.g. cone cells in the eye are light sensitive)
• Neurones are specialised to carry impulses from receptors to the CNS
• Lots of chloroplasts - lots of photosynthesising (e.g. mesophyll cells in the leaf)
• Root hair cells increase surface area so more water + mineral ions can be absorbed

Question 12

What is diffusion?

Answer 12

The spreading out of the particles of a gas or of any substance in solution

Question 13

What does the net movement into or out of cells depend upon?

Answer 13

The concentration of the particles on either side of the cell membrane

Question 14

What is concentration gradient?

Answer 14

The difference in concentration between two areas (of a cell)

Question 15

What increases the rate of diffusion?

Answer 15

A greater difference in concentration

(Steeper concentration gradient)

Question 16

Why do particles diffuse from an area of high concentration to one of low concentration?

Answer 16

Because the particles move randomly

Question 17

Give some examples of where diffusion occurs

Answer 17

• Oxygen into the cells of the body from the bloodstream as cells are respiring
• Carbon dioxide into actively photosynthesising plant cells
• Simple sugars and amino acids from the gut through cell membranes

Question 18

What is a tissue?

Answer 18

A group of cells with similar structures and function

Question 19

Give some examples of animal tissue

Answer 19

• Muscle tissue - can contract to bring about movement
• Glandular tissue - produces substances such as enzymes or hormones
• Epithelial tissue - covers some parts of the body

Question 20

Give some examples of plant tissue

Answer 20

• Epidermal tissue - covers the plant
• Mesophyll - can photosynthesise
• Xylem and phloem - transport substances around the plant

Question 21

What are organs?

Answer 21

Parts of the body made up of tissues that work together to carry out a task

Question 22

What is the stomach made of?

Answer 22

• Muscle tissue to churn its contents
• Glandular tissue to produce digestive juices
• Epithelial tissue to cover the outside and inside

Question 23

Give some examples of plant organs and what they contain

Answer 23

The leaf, stem, and root.

They contain epidermal tissue, mesophyll, xylem, and phloem

Question 24

What are organ systems?

Answer 24

Groups of organs that work together to perfom/carry out a particular function

Question 25

Draw a diagram showing the levels of complexity in a multicelled organism

Answer 25

Cell

Tissue

Organ

Organ system

Whole body

Question 26

What needs to happen to the food you eat and why?

Answer 26

Needs to be changed from insoluble molecules into soluble ones.

Only then can the soluble molecules be absorbed into the blood

Question 27

List and describe the functions of the organs that make up the digestive system

Answer 27

• Glands (e.g. pancreas and salivary gland) - produce digestive juices
• Stomach + small intestine - digestion occurs here
• Liver - produces bile
• Small intestine - absorbs soluble food
• Large intestine - water is absorbed from undigested food, producing faeces/shit