Cells and Tissues Flashcards
What are the 3 parts a cell can be divided into?
- Plasma (cell) membrane forms a boundary between what’s inside and outside of the cell
- Cytoplasm
- Cytosol liquid part
- Organelles functioning machinery that’s embedded within the cell - Nucleus
- Chromosomes/ genes
- Nucleolus
What makes up the Nucleus?
o Chromatin - DNA
o Nuclear pore - allow for the exit of the information from the DNA (mRNA)
o Nuclear envelope - defines the boundary of the nucleus
o Nucleolus - organelle found within the nucleus which helps make ribosome
What makes up the cytoplasm?
o Cytosol
o Organelles (except nucleus)
What is the function of the Rough endoplasmic reticulum (ER)?
o Network
o Has ribosomes on it (produce proteins)
What is the function of membrane bound ribosomes?
Produce proteins
What is the function of the Golgi complex?
Once the protein is produced by the ribosome and processed in the rough endoplasmic reticulum, the protein is further packaged up in the Golgi apparatus (prepares proteins for use in other places inside and outside of the cell)
What is the function of the mitochondrion?
Powerhouse of the cell / the energy used throughout the cell
What is the function of the smooth endoplasmic reticulum?
o Lacks membrane bound ribosomes
o Produces phospholipids (vital molecule required to produce the cell membrane (plasma membrane))
What is the function of the lysosome?
Breaks up debris (dysfunctional proteins/ deformed proteins) within the cell
What is the function of the lysosome?
Breaks up debris (dysfunctional proteins/ deformed proteins) within the cell
What is the function of the plasma membrane?
o Boundary that defines what is within and outside cell
o A flexible yet sturdy barrier that surrounds and contains the cytoplasm of the cell.
o Made up of phospholipid bi-layer
What is the function of the cytoskeleton?
Skeletal framework / shape and structure.
o Microtubules - they traverse the length and breadth of the cell. Highways and pathways in the cell.
o Microfilaments - help in the movement of a cell.
o Intermediate filaments - provide tensile strength to the cells.
What is the function of the microvilli?
Increase surface area. Helps in the absorption of nutrients in the intestines.
What is the function of the flagellum?
Help in the motility of the cell. E.g., sperm cell
What is the function of the cilium?
Moves about itself without the cell moving. Moves things around in the cell. E.g. too much mucus in the cell – cilium will help move the mucus away from the cell membrane
What makes up the plasma membrane?
o Make up of lipid bi-layer - composed of phospholipids
o Cholesterol – gives rigidity to the plasma membrane
o Proteins
- Integral proteins / transmembrane proteins - signal transduction
- Peripheral proteins - enzymatic reactions (in the cell (intracellular) or out of the cell (extracellular))
- Glycoproteins - identity markers (let the immune cells in the body know where the cell belongs / protects cell from being attacked by the immune cells)
What is the membrane permeability of the plasma membrane?
o Plasma membranes are selectively permeable
- Lipid bilayer is always permeable to small, nonpolar, uncharged molecules (e.g. oxygen)
- Transmembrane proteins that act as channels or transporters increase the permeability of the membrane (form the channels that allow molecules to pass through cell membrane e.g. glucose)
- Macromolecules are only able to pass through the plasma membrane by vesicular transport
What are the two gradients across the plasma membrane?
Concentration gradient and Electrical gradient
Together, make up an electrochemical gradient.
What is concentration gradient?
The difference in the concentration of a chemical between one side of the plasma membrane and the other
What is electrical gradient?
The difference in the concentration of ions between one side of the plasma membrane and the other
What are the three passive processes of transport across the plasma membrane?
- Simple diffusion
- Facilitated diffusion
- Osmosis
What are the two active processes of transport across the plasma membrane?
- Active transport
- Vesicular transport
What is simple diffusion?
o Doesn’t require the use of energy (ATP)
o Influenced by factors:
- Steepness of the concentration gradient
- Temperature
- Mass of diffusion substance
- Surface area
- Diffusion distance
What is facilitated diffusion?
o Molecules move from a region of high concentration to low concentration
o Facilitated by a channel (aquaporins)
