4.1.1 CELL STRUCTURE

?
  • Created by: Raheela
  • Created on: 02-01-19 19:19

4.1.1.1 Eukaryotes and Prokaryotes

What are prokaryotes?

Single celled organisms which contain a DNA loop floating freely in their cytoplasm

The mitocondria and the nucleus are missing 

They contain cytoplasm, cell wall (no cellulose), cell membrane, small rings of DNA called PLASMIDS and ribosomes (smaller than in eukaryotes)

What are Eukarotes?

Plant, animal, fungi and protists are examples of eukaryotes

They contain genetic material enclosed in a nucleaus, cytoplasm and cell membrane. These cells contain mitocondria and ribosomes 

1 of 8

4.1.1.1 ANIMAL CELLS

NUCLEUS - controls the activity of the cell. Contains chromosomes which carry genes which are the instructions for making proteins needed to build new cells or organisms

MITOCONDRIA - structures in the cytolpasm where aerobic respiration takes place.

RIBOSOMES - where protein synthesis takes place (making new proteins)

2 of 8

4.1.1.1 PLANT CELLS

CELL WALL - made of cellulose to strengthen the cell wall and give the plant cell support.

PERMANENT VACUOLE - a space in the cytoplasm filled with cell sap which keeps the cell rigid and supports it.

CHLOROPLASTS - contain a green chemical called chlorpophyll which absorbs light so that plants can make food by photosynthesis.

3 of 8

4.1.1.1 BACTERIAL CELL

PLASMID - small rings of DNA which code for features such as antibiotic resistance. These can be passed onto other bacteria and allow them to also become resistant to antibiotics

CYTOPLASM - site where most chemical reactions take place.

GENETIC MATERIAL - single loop of DNA found in the cytoplasm with no nucleaus around it.

4 of 8

4.1.1.1 BACTERIAL CELL 2

CELL MEMBRANE - controls the passage of substances in and out of the cell.

CELL WALL - strengthens the cell but the wall is not made from cellulose as plant cell walls are.

SLIME CAPSULE - protects the cell and stops it from drying out when bacterial cells are in the air.

FLAGELLUM - a long protein strand that lashes about to move the cell when in water. Not all bacterial cells will have these.

Notes: bacterial cells will divide by making copies of themselves and splitting into two cells. This process is called binary fission.

5 of 8

4.1.1.1 Similarities & Differences

Feature               Animal Cells              Plant Cells             Bacterial Cells

Nucleus                     YES                        YES                        NO

Cytoplasm                  YES                        YES                        YES

Cell Membrane           YES                        YES                        YES 

Cell Wall                    NO                          YES                        YES

Ribosomes                 YES                         YES                        YES 

Mitocondria              YES                         YES                        NO

Chlorplasts               NO                           YES                       NO

6 of 8

4.1.1.1 SCALE & SIZE

Metre                       1m                                                        10^0

Centimetre               0.01m                                                   10^-2

Millimetre                0.001m                                                 10^-3

Micrometre             0.000001m                                           10^-6

Nanometre              0.000000001m                                     10^-9

Picometre                0.000000000001m                               10^-12

7 of 8

4.1.1.1 Order of magnitude

Order of magnitude are used make approximate comparisons between numbers or objects.

If a number is 10 times bigger than another number then it has an order of magnitude bigger or 10^1

If a cell is 100 times bigger than another cell then it is two orders of magnitude bigger or 10^2.

eg: 100/10 = 10 therefore 10^1

1000/10 = 100 therfore 10^2

8/2 = 4 therfore they both have the same order of magnitude because the answer if less than 10. 

8 of 8

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cells, tissues and organs resources »