Wk 2 Flashcards
Cell Function: Organelles and Cellular Processes
What are the components of the plasma membrane?
- Phospholipids
- Proteins
- Carbohydrates
- Cholesterol
What are the functions of the plasma membrane?
- Barrier separating the inside and outside of the cell
- Controls the passage of materials between the inside & outside of the cell.
- Allows the cell to be identified to other cells
- Involved in intracellular signalling
What are the types of membrane transport?
Passive (no energy required - moves down conc. gradient)
Primary Active (energy required - moves up conc. gradient)
Secondary Active (energy required - moves up conc. gradient)
What are the types of passive transport?
Simple Diffusion: moves through the lipid bilayer of membrane.
Facilitated Diffusion (proteins helping move molecule through):
- Channel mediated diffusion; solute moves down conc. gradient through channel
- Carrier mediated diffusion; solute binds to carrier to be transported
- Osmosis diffusion; water moves from high conc. to lower conc.
What is primary active transport?
Na+/K+ Pump:
- Energy is obtained by hydrolysis of ATP to ADP
- Changes the shape of a carrier protein
- “Pumps” a substance across the membrane
What is secondary active transport?
- Involves two molecules passing through simultaneously
- Energy is taken from the ions that passively leaking back through the cell
- Energy is released allowing other substances to pass through the membrane against their own concentration gradient at the same time
What are symporters?
Move TWO substance across the membrane in the same direction.
What are Antiporters?
Move TWO substance across the membrane in different directions.
What is a nucleus?
- Controls the cellular structure
- Produces ribosomes in nucleoli
- Directs cellular activities
- Houses genetic information
What are the types of endoplasmic reticulum (ER)?
Rough Endoplasmic Reticulum (RER)
- Producing, transporting and storing proteins to be exported to the outside of the cell
Smooth Endoplasmic Reticulum
- Carbohydrate or lipid or steroid synthesis
-Enzymatic degradation (detoxification)
- Special role in muscles
What are ribosomes?
- Responsible for protein synthesis: translation (make proteins)
What is the golgi appartus?
- Modifies, sorts, packages and transports proteins from ER
What are lysosomes?
- Formed from the golgi apparatus
- Contain powerful digestive enzymes
Autophagy – digestion of organelles
Autolysis – destroy the cell
What is mitochondria?
- Generate ATP with aerobic cellular respiration
- Powerhouse of the cell
What is endocytosis?
Cell acquires material from extracellular space/fluid (move things into cell).
What is exocytosis?
Materials move out of cell into the extracellular space (eliminate things from cell).
What are the stages of the cell cycle?
Interphase - cell maintains and carries out normal metabolic functions preparing for division.
Mitotic phase - cell divides in two.
What are the enzymes that assist in DNA replication?
Cyclin Dependent Protein Kinases (CDKs) - initiation and regulation of the DNA replication.
Cyclins (cellular protein) - responsible for turning CDKs on.
What are the stages of Interphase?
G1 Phase
- Growth
S Phase (synthesis)
- Growth
- DNA replication
G2 Phase (makes more organelles)
- Growth
*Centrioles split and separate.
What are the stages of Mitosis (somatic cells)?
- Prophase (spindle fibres form from centriole, chromosomes form)
- Metaphase (chromosomes line up down the middle)
- Anaphase (chromosome pulled to opposite ends)
- Telophase (spindle fibres break)
- Cytokinesis (2 separate cells are formed)
*46 chromosomes, Diploid cells (2n)
What are the stages of Meiosis I?
- Prophase I
- synapsis occurs which allows for genetic variation (maternal/paternal replicated chromosomes pair up)
- Four sister chromatids (tetrad)
- Crossing over occurs (to mix up genes) - Metaphase I
- chromosomes line up in pairs
- spindle fibres attach to centromeres (different to mitosis) - Anaphase I
- Pairs separated and pulled to opposite ends of cell - Telophase I/Cytokinesis
- Produces 2 new cells
*23 replicated chromosomes, 2 haploid cells (n)
What are the stages of Meiosis II?
Prophase II
- Spindle fibres form from centromere
- NO crossing over
Metaphase II
- Align the replicated chromosomes along the equator
Anaphase II
- Sister chromatids pulled apart to opposite ends of cell
Telophase II/Cytokinesis
- 4 new genetically different daughter cells are created
*23 chromosomes only, 4 haploid cells (n)
What are stem cells?
Stem cells are cells that can turn into other cell types.
- can replace cells and tissues that have been lost/damaged to disease.
What are the types of stem cells?
Pluripotent - can turn into any cell
Multipotent - can turn into specific cell types
Totipotent - can form an entire organism
