Human Cellular Structure Flashcards
Function of the plasma membrane?
Controls material that enters exits the cell.
Function of the nucleus?
Contains DNA for protein synthesis.
Function of the nucleolus?
Found in nucleus & makes ribosomes.
Function of the nuclear envelope?
A double membrane surrounding the nucleus with pores allowing mRNA to leave the nucleus.
Function of the smooth ER (endoplasmic reticulum)?
Synthesis of lipids and carbohydrates
Function of the rough ER (endoplasmic reticulum)?
Ribosomes on the surface of the R - ER for protein synthesis.
Function of the Golgi apparatus?
Packages membranes into membrane sacs for transport around the cell.
Function of the mitchocondria?
Site of aerobic respiration for the synthesis of ATP.
Factors that affect the rate of transport of substances across a cell membrane?
- Concentration gradient
- temperature
- surface area of the membrane
- size of molecules
- membrane thickness
Define diffusion:
Net movement of molecules from a higher concentration to an area of lower concentration
( down concentration gradient) = until equilibrium is reached.
= passive = doesn’t require ATP
Define osmosis:
The net movement of water molecules from an area of high water potential to an area of lower water potential, across a permeable membrane.
Passive process= no ATP
Osmosis happens until water potential is equal on both sides.
Define facilitated diffusion:
Passive movement of specific molecules or ions across a cell membrane ( channel or carrier proteins)from a were of high concentration to low concentration.
( down concentration gradient)
Define active transport:
Movement of molecules or ions from an area of lower concentration to an area of high concentration
(Against concentration gradient)
=Uses energy from ATP & carrier proteins
E.g= allows cells to absorb substances even when they are in lower concentration outside the cell rather than inside= mineral ions absorbed by root hair cells
