Cell Structure and Function Flashcards
What is the structure that allows molecules to move into and out of the nucleus? What is it embedded in?
Nuclear pores which are embedded in the nuclear envelope
Where is the ER located?
Right up to the nuclear envelope with the rough ER pressing closest against it and the smooth after.
Where can ribosomes be found?
Free - floating (in the cytosol) or membrane bound (bond to the rough ER)
Where do ribosomes made by the rough ER function?
Outside of cells or in the membrane
Where do proteins made by free floating ribosomes function?
Within the cell
What are the functions of the rough ER?
Make proteins and membranes - the factory
Function of the smooth ER. Anything to note?
Dependent on the specific cell. Some functions are liver/kidney detoxification, steroid-based hormones and Ca for muscle contractions.
What does the cytoplasm contain?
Cytosol, mostly membrane-bound organelles, inclusions such as chemical substances and nutrients, melanin
What is the function of the Golgi apparatus?
Accepts transport vesicles from the ER for further processing.
Mainly sorts, might modify, and packages proteins into another vesicle before “shipping” them off to their final destination.
What are lysosomes and peroxisomes? What is their function and where can they be found?
Membrane bound vesicles (organelles) which contain enzymes.
Lysosomes break down organic material inside of them
Peroxisomes degrade toxic molecules inside of them
Can be found floating throughout the cytoplasm, as they bud off the ER and Golgi apparatus
What does mitochondria carry out?
Aerobic respiration.
How is the energy released by aerobic respiration stored? How does this molecule release energy?
As Adenosine Triphosphate. The three phosphates are negatively charged so the repulsion supplies a lot of potential energy in the bonds. The breakage of the terminal phosphate releases energy.
(BTW adenosine is just adenine and ribose)
Summarise the protein synthesis pathway.
DNA copied into mRNA which travels to the ribosomes either in the rough ER or free floating ones. tRNA, codons matched with the conjugate amino acids, joined by peptide bonds to make a protein. Protein packed into a vesicle travels to the Golgi where it is sorted, possibly modified and shipped off to its destination (in cell/membrane, out of cell, or into an organelle like the lysosome/peroxisome).
Functions of the plasma (cell) membrane
Mechanical barrier between intracellular fluid (ICF) and extracellular fluid (ECF).
Selectively permeable
Electrochemical gradient
Communication and cell signalling
Membrane proteins functions
- Transport of molecules between ICF and ECF
- cell communication
- attaching to extracellular environment or other cells
- cell to cell recognition
- enzymes activity
