Cell Structure

Question 1

What are cells?

Answer 1

The basic units of all forms of life

Cells come together to form communities

Question 2

What are eukaryotes and what do they contain?

Answer 2

Eukaryotic cells have cytoplasm, cell membrane, nucleus with genetic material
Plant and animal cells are eukaryotes
Eukaryotes evolved from prokaryotes perhaps 1.5-2 billion years ago

Question 3

What are prokaryotes and what do they contain?

Answer 3

Bacterial cells are prokaryotic
Smaller in comparison 1000-10000 times smaller
Cytoplasm and membrane surrounded by a cell wall
Genetic material not enclosed in a nucleus
It is a singe DNA loop and maybe more DNA rings called plasmids

Question 4

What do most animal cells contain?

Answer 4

Nucleus
Cytoplasm 
Cell membrane 
Mitochondria 
Ribosomes

Question 5

What do plant cells also contain?

Answer 5

Chloroplasts
Permanent vacuole filled with cell sap
A cell wall made of cellulose strengthening the cell

Question 6

What are the common specialised animal cells?

Answer 6

Sperm
Nerve
Muscle

Question 7

What are the common specialised cells in plants?

Answer 7

Root hair cells
Xylem
Phloem

Question 8

What is cell differentiation?

Answer 8

As an organism develops cells differentiate to form different types of cells
Most types of animal cells differentiate at an early stage
Many types of plant cells retain ability to differentiate throughout life

Question 9

Why do cells differentiate?

Answer 9

To perform specialised functions
In mature animals cell division is mainly retracted to repair and replacement
A differentiated cell acquires different sub cellular structures so it can carry out specific functions

Question 10

Explain the purpose of the root hair cell?

Answer 10

Close to the tips of growing roots

Plants take in water through them, large surface area and thin walls

Question 11

Explain photosynthetic cells?

Answer 11

Contain chloroplasts
Continuous layers in leaves or stem to absorb sunlight
Large vacuole keeps cell rigid through osmosis

Question 12

Explain xylem cells?

Answer 12

Transports water or mineral ions from roots to leaves
Cells fill with lignin and die making hollow tubes
Spirals of lignin make cell wall strong

Question 13

Explain phloem cells?

Answer 13

Transport tissues carrying food
Spiral cells
Cell walls break down to make sieve plates
Supported by other cells

Question 14

Explain sperm cells?

Answer 14

Long tail full of mitochondria to make tail work
Acrosome stores enzymes
Large nucleus with genetic information

Question 15

Explain nerve cells?

Answer 15

Carry electrical impulses
Lots of dendrites to join with the nerve cells
Axon carries nerve impulse along body and has lots of mitochondria

Question 16

Explain muscle cells?

Answer 16

Straightened cells contract and relax in pairs
Contains special protein that contracts
Many mitochondria for energy transfer 
Stores glycogen 
Used in cellular respiration

Question 17

What does a vacuole contain?

Answer 17

Cell sap

Question 18

What does cellulose do?

Answer 18

Forms cell walls and keeps cells in rigid shape

Question 19

What do chloroplasts contain and what do they do?

Answer 19

Contain chlorophyll

Make food through photosynthesis

Question 20

What is the role of a cell membrane?

Answer 20

Holds cell together

Controls what goes in and out of the cell

Question 21

What does cytoplasm contain?

Answer 21

Enzymes - cytoplasm is where chemical reactions happen

Question 22

What controls the cell and what is the exception in animal cells?

Answer 22

Nucleus

Red blood cells

Question 23

What is different about bacteria cell?

Answer 23

Prokaryotes cells - means before nucleus
1000-10000 times smaller than eukaryotes 
Much simpler
Has genetic material 
Plasmids
Cytoplasm
Cell membrane 
Cell wall
Flagella
Slime capsules

Question 24

How are leaves adapted for photosynthesis?

Answer 24

Waxy cuticle - prevents water loss
Spongy mesophyll - not tightly packed together but allows CO2 and has irregular cells
Guard cell and stomata are specialised doors so CO2 and O2 can’t diffuse into leaf - on bottom of the leaf to limit water loss
Xylem and phloem - move water/solutes and food from leaves to plant
Palisade - lots of chloroplasts, block shaped, catch sunlight for photosynthesis, packed into layers

Question 25

What is the function of nucleus

Answer 25

Controls all activities of cell

Surrounded by nuclear membrane

Question 26

What is the function of mitochondria

Answer 26

They are structures in cytoplasm where aerobic respiration takes place releasing energy from the cell

Question 27

What is the function of ribosomes

Answer 27

Where protein synthesis makes all proteins needed in a cell