4.1.1.1 Eukaryotes and Prokaryotes Flashcards
Are animal and plant cells eukaryotic or prokaryotic cells?
Eukaryotic Cells
Prokaryotic Cells
- Genetic material is not enclosed in the nucleus and it doesn’t have membrane bound organelle it is also smaller in comparison to a eukaryotic cell
- Much smaller in comparison to eukaryotic cells
- Have a cytoplasm and a cell membrane which is surrounded by a cell wall
- The cell wall isn’t made of cellulose like a plant cell wall, it is made of peptidoglycan which means it isn’t was rigid
- Genetic material isn’t enclosed in the nucleus, it is a single DNA loop found in the cytoplasm
- There may be one or more small rings of DNA called plasmids
- Bacteria cells are prokaryotic cells
What type of organisms are bacteria cells?
- single celled (unicellular) organisms
- prokaryotic cells
What are bacteria cells made up of?
- cytoplasm
- cell membrane
- cell wall
- genetic info is not enclosed in a nucleus - it is a single looped chromosome found free in the cytoplasm
- plasmids
- ribosomes
- flagella
- capsule(most bacteria)
- pili
Function of Flagella:
- a tail for movement
- found on sperm cells as well
Function of Capsule (most bacteria):
- For protection from damage
- For sticking prokaryotic cells together
Function of Pili:
- For directional movement
- For sticking to surfaces e.g. bacteria may stick to a body of cells to begin causing diseases
Eukaryotic Cell:
- type of cell which contains its genetic material (DNA) enclosed in its nucleus, and has other membrane bound organelle like mitochondria
- has a cell membrane and a cytoplasm
Function of Plasmids:
- in bacteria cells
- extra circular bits of DNA
- unlike chromosomal DNA, plasmid DNA can move from one bacterium to another
- transfers genetic material from one cell to another
- genes in the plasmid can be for anti-biotic resistance
- some produce toxins
What was the classification system like pre-1970?
- Living things were classified into 5 kingdoms
- They were classified based on observable characteristics
- Bacteria and archaea were grouped together
Archaea:
uni-cellular organisms that are extremophiles (love extreme places) as they live in extreme places e.g. under water volcanoes
What was the classification system like post-1970?
A 3 domain system was developed that separated bacteria and archaea
Why were archaea and bacteria separated in the post-1970 classification system?
- Although the size and structure of archaea ribosomes are the same as bacteria (which is why they were put in the same kingdom pre – 1970) the nucleic acid in the archaea ribosomes were more like eukaryotes whereas bacteria are prokaryotes.
- DNA sequencing showed archaea DNA was nothing like bacteria DNA – unlike ‘anything we’ve ever seen’.
How do you calculate cell magnification from an image?
Magnification = Image Size/Actual Size
How do you calculate order of magnitude?
- Convert to same unit
- Put in standard form
- Find difference between powers
