Cell Biology

Question 1

What are Eukaryotic cells

Answer 1

Found in plants animals fungi and protists
They are 10-100micro metres in size
A eukaryote is made up of eukaryotic cells
Larger than a prokaryote

Question 2

What is a prokaryote

Answer 2

Bacteria
Contain small rings of DNA called plasmids - can replicate and move between cells so frenetic information is shared
Don’t have a nucleus
Does not have mitochondria - can’t respire
No chloroplast - no photosynthesis

Question 3

What does the nucleus do

Answer 3

Controls what comes in and out of the cell

Contains chromosomes - the genetic material of the cell

Question 4

What does mitochondria do

Answer 4

Where aerobic respiration happens - sugar and oxygen releases energy

Question 5

Cytoplasm

Answer 5

Where most of cells chemical reactions take place

Question 6

What is in a plant cell

Answer 6

Permanent vacuole - fluid filled sac that stores water , enclosed in a membrane and can make 99% of cells volume
Chloroplast
Cell wall

Question 7

Differentiation in plants

Answer 7

Can differentiate throughout their lives

Therefore can always make new tissues

Question 8

Animals differentiation

Answer 8

Early on in their development
In mature animals cells mostly divide once and replace and repair tissue
New tissues are rarely made by cell differentiation

Question 9

What does bacteria contain

Answer 9

Cell wall 
Cell membrane
Cytoplasm
Some bacteria have flagella for movement
Plasmids which are small rings of DNA

Question 10

Where is DNA stored in prokaryotic cells

Answer 10

In the cytoplasm

Question 11

What size are eukaryotic cells

Answer 11

10 - 100 micrometers

Question 12

What is cell differentiation

Answer 12

The process where a cell develops new sub-cellular structures to let it perform a specific function.

Question 13

Differentiation in embryos

Answer 13

Happens during organisms development
Starts as one cell
Cell divide to form embryo that differentiates (specialises) to produce cells that can perform all of the body’s functions

Question 14

Differentiation in plants

Answer 14

Many plants keep their ability to differentiate throughout their life
Always able to create new tissues

Question 15

Differentiation in adult animals

Answer 15

Rare
Cells mostly divide in order to replace cells and repair tissue
New tissues are rarely created

Question 16

Structure of sperm cell

Answer 16

Middle section is filled with mitochondria to provide sperm energy it need to travel to reach the egg
Head caries nucleus which carries one half or organisms genetic material (haploid cell)
Across me at tip of head, contains digestive enzymes needed to penetrate into egg cell
Flagellum used for cells motion

Question 17

What does the sperm do with the egg

Answer 17

Fuses with egg, sharing it’s genetic information to make a complete genome

Question 18

What’s in a nerve cell

Answer 18

Axon - part of cell that electrical signals travel along
Nerve cells have a long axon. Which increases the distance that electrical signals can travel
Myelin sheath stops electrical signals leaking out the nerve cell and increases speed on transmissions
Dendrites are branches of nerve cells that transfer electrical messages to other neutrons and electrical messages between neutrons at synapses

Question 19

What do muscle cells have

Answer 19

Mitochondria to generate energy for motion

Protein fibres within cell can contract allowing the muscle to move

Question 20

Root hair cell structure

Answer 20

No chloroplast because they are located underground

Long projections which increase SA that plant used to absorb water and minerals

Question 21

Xylem cell structure

Answer 21

Open ended cells
Made up of a series of connected dead xylem cells
The end walls of the dead cells are broken to allow water to move through
Longing strengthens the cell walls of xylem cells

Question 22

Phloem structure

Answer 22

Transports food products to parts of plant that are needed. Made up of columns of living cells
End walls contain small holes to allow food products to move up and down the phloem vessel throughout the plant

Question 23

What is resolution

Answer 23

The ability to distinguish between two or more objects that are close together

Question 24

Equation for magnification

Answer 24

Image size / actual size

Question 25

Light microscopes

Answer 25

Passes light through specimen and creates a magnified image using lenses
First light microscope was made using two lenses towards the end of 16th century and had a better resolution than the eye

Question 26

Electron microscope

Answer 26

First used in 1933
Electrons are passed through specimen instead of light
Can resolve distances of 1 nm with magnifications of x500,000

Question 27

Light microscope experiment

Answer 27

Put thin sample of tissue (onion epidermis ) on microscope slide
Add few drops of a suitable stain/dye
Place a coverslip on top of the tissue and place the slide onto the microscope stage
Use objective lens with lowest magnification and focus on sample
Increase magnification and refocus to see different features of cells

Question 28

Equation for calculating the population of bacteria is….

Answer 28

Future pop = current pop x 2 time passed / mean division time

Question 29

Describe process of binary fission

Answer 29

Prokaryotic cell
Genetic material is replicated
Cell grows
Two large circular strands move to opposite sides of cell
Plasmids are randomly spaced out
Starts to divide
New membrane and cell wall formed around 2 new cells

Question 30

optimum Conditions for bacteria to reproduce rapidly

Answer 30

Warm environment

Plenty of nutrients

Question 31

What is mitosis

Answer 31

The process that produces two genetically identical cells

Question 32

Where are plant stem cells found

Answer 32

Meristem tissue

Question 33

Where are stem cells in humans found

Answer 33

In bone marrow and other tissues and organisms

Embryos

Question 34

What are antigens

Answer 34

Proteins found on the surface of cells

Wbc can detect foreign antigens on the surface of the skin and produce protein molecules called antibodies