MODULE 1 Flashcards
What common features do prokaryotes and eukaryotes share?
They both have DNA (pro=circular, euk=linear), ribosomes, cytoplasm and a cell membrane
What is a prokaryote?
Prokaryotes aren’t membrane bound and don’t have any membrane-bound organelles. Prokaryotes have a cell membrane, a cytoplasm, ribosomes and genetic material. It doesn’t have a nucleus and have one circular chromosome. They are usually apart of unicellular organisms, either bacteria or archaea.
What is a eukaryote?
Eukaryotic cells are much more complex than prokaryotes, and are also larger in size. They have membrane bound organelles, multiple linear chromosomes and a nucleus.
Organelles are structured and carry out processes such as respiration and photosynthesis.
What are light microscopes?
- Limited in magnification
- Resolution of around 0.2 micrometres or 200 nm
- Observed living cells
- They pass light through a specimen
- Lenses magnify the specimen
What is a TEM?
- 2 dimensional image
- No living specimens can be observed
- Passes electrons through a specimen, witha strong magnetic field that acts as a lens to produce a very high definition cross section.
- High quality, high resoltion
What is an SEM?
- Has a large depth of field so it can be used to examine the surface structure of specimens
- It bombards solid specimens with a beam of electrons with causes secondary electrons to be emitted from the specimen.
- Electrons bounce off surfaces
- It is 3 Dimensional
- No living specimens can be observed.
What is the ER? How does structure relate to function?
-Networks of flattened, interconnected membranes, channels hat run through the cytoplasm, If something has to move throughout the cell, it is done through the ER
-Provides a connection of pathways between the nucleus and the cell’s environment, allowing for intracellular transport.
The main function of ER is transport, and also plays a role in processing cell products.
What is the difference between the smooth ER and the rough ER?
The rough ER processes proteins made by the cell and can synthesise lipids
Smooth ER is the main site of lipid production
What is the nucleus? How does structure relate to function?
Large organelle bound by a double membrane
-This membrane has tiny pores that regulate the passage of substances between the nucleus and the cytoplasm.
Controls the activity of the cell
-The tiny pores allow communication from the nucleus and the cytoplasm.
What is the mitochondrion? How does structure relate to function?
-The inner membrane (cristae) is heavily folded and has an increased surface area.
The increased surface area allows for the attachment of enzymes responsible for energy production within the cell. Therefore, more surface area equals more energy production.
What are lysosomes? How does structure relate to function?
-Lysosomes contain digestive enzymes that are responsible for splitting compound chemical compounds into simpler ones.
The simple compounds created by the digestive enzymes are used as building blocks for new compounds and organelles (recycling)
-The membrane ruptures, releasing the enzymes inside which then digest the cell, killing it in the process.
What are chloroplasts? How does structure relate to function?
-Liquid part of the chloroplast named the stroma
-Layered membranes
Contains membrane stacks called thylakoids. Chlorophyll is found in thylakoids.
-Layering of thylakoids increases the surface area over which chlorophyll occurs, meaning more sunlight can be absorbed for photosynthesis.
What is the golgi body? How does structure relate to function?
-Flat membranes, flattened sacs that bud off into vesicles
The vesicles are the secretory function of the golgi
-Modifies proteins and packages them for cell export, and also determining where they will go, it can be transported into the cell or out.
What is a ribosome?
Ribosomes are the site of protein synthesis within the cell. Ribosomes are made of RNA and protein, and they are the machinery that carries out genetic instructions of DNA to produce any proteins that are needed for cell functioning and structure.
What is the fluid mosaic model?
The membrane is composed of a bi layer of phospholipids in which proteins and other molecules are suspended. The materials needed by the cell or any waste are able to cross the membrane via trans membrane proteins.
What is a selectively permeable membrane?
Allows certain molecules to pass through the microscopic pores. For example, it will let water (solvent) out but may stop dissolved particles (solute) from passing through.
15.What are the structures in the cell membrane that are responsible for flexibility, the movement of ions into cells and the ability to bind hormones.
- Lipid component- flexibility and self repair
- Membrane proteins suspended in the bi-layer- act as pores or form active carrier systems for transport- allow the exchange of substances between the cell and the cell environment. Ions use these channels to engage in facilitation diffusion into the cells.
receptor proteins- ause the cells to respond to certain stimuli and signals.
Why is it called the fluid mosaic model?
The fluid component of the model is the phospholipid bilayer. It is not rigid in structure, but very fluid. It has the ability to flow and change shape. The phospholipid bilayer is referred to as a mosaic as there are various molecules and proteins that aer embedded into the lipid bilayer, like a mosaic. The floating proteins are the mosaic.
