Cell Ultrastructure (Prokaryotes And Eukaryotes) Flashcards
What do prokaryotes and eukaryotes have in common?
Plasma membrane, ribosomes, DNA, RNA, cytoplasm
Differentiate between prokaryotes and eukaryotes
Prokaryotes have no-
1. Centrioles
2. Nucleus
3. Membrane bound cell organelles.
Prokaryotes have got-
1. Peptidoglycan cell wall
2. Smaller ribosomes
3. Naked loop of DNA
4. plasmids
what is the structure and function of the centrioles?
it is present only in animals.
1. two bundles of microtubules at right angles.
2. used as an anchor point to seperate chromosomes during cell division.
3. they form the basis of the cilia.
what is the structure and function of the rough ER?
- it is a system of fluid filled membranes studded with ribosomes.
- It is continuous with the nuclear membrane.
3, its large surface area formed by lots of folding enables protein synthesis on a larger scale.
4, proteins pinched of in vesicles are transported to the golgi apparatus.
what are the main structures of all eukaryotic cells?
nucleus; nucleolus; cytoskeleton; cytop1lasm; plasma membrane; golgi apparatus; rough ER; smooth ER; ribosomes; mitochondria
what is the structure and function of the golgi apparatus?
- it is a stack of membrane bound sacs
- vesicles from the RER join at the cis face.
- here they are modified to form glycolipids and glycoproteins by adding lipids and proteins.
- it folds proteins into their 3D shape.
- modified proteins are pinched off from the trans face and transported through transport vesicles.
what is the structure and function of the flagella?
it has 9 pairs of microtubules surrounding two lone microtubules. it is covered by a membrane.
it is used to move unicellular organisms around.
what is the structure and function of the cytoskeleton?
it has microfilaments made of actin- allow cell movement and cytokinesis
microtubules made of scaffold like structures to give cell shape
intermediate fibres give mechanical strength, maintaining integrity
What structures are involved in the production of proteins?
Nucleus, RER, transport vesicles, golgi apparatus
How do prokaryotes divide
Binary fission
How do prokaryotes divide
Binary fission
What is the structure and function of the cell wall?
It is present in plants and fungi only. It is made up of cellulose in plants and chitin in fungi. it provides structure and support to the cell, maintaining the cells shape. It prevents the cell from bursting when turgid. It is permeable to allow solutions through.
What is the structure and function of the plasma membrane?
It is made up of the phospholipid bilayer, cholesterol, proteins, glycoproteins, lipids, glycolipids.
It seperates cell contents from the external environment. Controls what enters and leaves the cell. It acts as a receptor for various chemicals; site of chemical reactions.
Structure and function of the chloroplasts
It is double membrane bound, the inner membrane forms flat discs filled with chlorophyll called thylakoids, in stacks called granum.
These are surrounded by a fluid matrix called the stroma. It contains its own DNA and 70s ribosomes. It is the site of photosynthesis.
Structure and function of the nucleus
It is surrounded by a double membrane/ nuclear envelope. Contains chromatin (DNA wound around histones). It stores the genome and controls the cell by providing instructions for protein synthesis.
