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
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)
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.
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.
4.1.1.1 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.
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
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
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.
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