3.1 - 3.4 : Prokaryotic and Eukaryotic Cells Flashcards
What are all living organisms are made up of ?
all living organisms are made of one or more cells, sharing some common
features.
What common features do cells share ?
The cells of all living organisms share some common features
- Cell surface membrane
- Cytoplasm
- DNA
- Ribosomes
Name the 3 points of the cell theory
- All living organisms are made of cells.
- The cell is the building block of life in all living things.
- All cells are produced by the division of pre-existing cells.
There are two fundamentally different types of cell:
Prokaryotic and Eukaryotic
Example of Prokaryotic cells (Prokaryotes)
Bacteria and Archaea - They are unicellular meaning they are single-celled organisms.
Examples of Eukaryotic cells (Eukarya)
Protist, Plant, Animal, Fungi - They can be Unicellular or Multicellular
- Eukaryotic means ‘true nucleus’
REMEMBER - EUKARYOTIC = YOU = ANIMAL
Prokaryotic cell features
- No nucleus or chromosomes
- DNA is not associated with any histone proteins and lies free in the cytoplasm
- Peptidoglycan cell wall always present
- No membrane bound organelles e.g. mitochondria
- Vast in number
- Extremely small (0.5-5µm) - much smaller than eukaryotic cells
- Cytoplasm
- Mesosme
- Cell wall
- 70s ribosmoes
Similarites of Prokaryotic cells and Eukaryotic cells
- Both have DNA (genetic material)
- Both have ribosomes (small organelles that make protien)
- Both have cytoplasm (jelly fluid within cells)
Name all the parts of the ultra structure of eukaryotic cells.
nucleus, nucleolus,
ribosomes, rough and smooth endoplasmic reticulum (RER and SER) , mitochondria, centrioles,
lysosomes, and Golgi apparatus
Name all the parts of the ultra structure of prokaryotic cells.
cell wall, capsule,
plasmid, flagellum, pili, ribosomes, mesosomes and circular DNA.
The nucleus functions.
- Only eukaryotic cells have a nucleus.
-
Functions :
- Production of mRNA for protein synthesis
- Retain the genetic material of the cell in the form of
DNA - Manufacture ribosomes
- To start the process of cell division.
Name all the parts in the nucleus
-
Endoplasmic reticulum :
- rough and smooth - Nucleolus
- Chromatin
- Nucleoplasm - think of cytoplasm
- Nuclear pore
- Nuclear envelope
- Ribosome
RER
Rough Endoplasmic Reticulum (RER)
The MS ANSER FOR RER IS - Where the protiens or polypetide is folded.
RER is formed from folds of membrane continuous with the nuclear envelope (it’s an extenstion of the nuclear envelope)
The surface of RER is covered in ribosomes
It facilitates protein synthesis by providing a large surface area for ribosomes. It then transports the newly synthesised proteins to the Golgi apparatus for modification.
Smooth endoplasmic reticulum (SER)
- SER is also formed from folds of membrane but its function is distinct from the RER, it synthesises lipids including cholesterol and steroid hormones (such as oestrogen).
- SER does not have ribosomes on its surface
Nucleolus
- The nucleolus is the largest nuclear organelle.
- The function is to produce and assemble the cell’s ribosomes. The nucleolus is also where ribosomal RNA genes are transcribed.
Chromatin
- Chromatin is composed of nucleosomes, which are a complex of DNA and proteins.
- Chromatin is a thin and long fibre
- Found throughout the cell cycle.
- The main function of chromatin is to package DNA into a unit capable of fitting within the tight space of a nucleus.
Nucleoplasm
- The fluidlike substance in the nucleus of a cell in which the nucleolus and chromatin are suspended.
- The principal function of the nucleoplasm is to program as a suspension substance for the organelles inside the nucleus.
Nuclear pore
- Nuclear pores are tiny openings present in the nuclear membrane of the nucleus. They are formed by the fusion of two nuclear membranes.
- Function : allows small molecules and ions to freely pass, or diffuse, into or out of the nucleus.
Ribosome
A ribosome is an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell. The ribosome reads the messenger RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins.
The Golgi apparatus
- A group of fluid filled membrane-bound flattened sacs surrounded by vesicles.
- Modify + package proteins and lipids
- Package them into secretory vesicles for transport
- They also make lysosomes ( a special type of Golgi vesicles) the site of lysosome synthesis.
Golgi vesicles
- Made by Golgi apparatus
- Store and transport proteins and lipids
- Can transport proteins and lipids out of the cell
Lysosomes
- Special type of Golgi vesicles
- They contain digestive enzymes
- ( they go around hydrolysing thing especially pathogens and old cell organelles - called lysosomal enzymes)