Unit 2: Cellular Physiology Flashcards
What are the three main components of the cell?
-A plasma membrane, nucleus and cytoplasm
What is the purpose of the Plasma Membrane?
Oily layer that separates the ICF from the ECF.
-Allows for selective permeability of substances
What constitutes the Nucleus?
- Double membrane layer that has nuclear pores which allow for selective materials in and out of the nucleus
- Contains DNA for protein synthesis & to hold genetic information
What is mRNA?
Delivers the coded message to ribosomes which “read” mRNA templates and translate it into a proper amino acid sequence
What is rRNA?
-An essential component of ribosomes.
What is tRNA?
-Transfers the appropriate amino acids within the cytoplasm to their designated site in the synthesizing protein.
What is the cytosol?
Semi-fluid medium in which many biochemical events occur within. Contains all the macromolecules.
What is the cytoskeleton?
- Protein network that gives the cell its shape, provides internal organization and regulates its various movements.
- ->Consists of microfilaments, intermediate filaments and microtubules.
What are organelles?
Compartments within the cells that carry out specific tasks. There are 6 organelles:
ER, golgi, lysosomes, peroxisomes, mitochondria and vaults.
Components of the RER?
- Studded with ribosomes, so it undergoes protein synthesis.
- Proteins can be transported within the cell or secreted elsewhere throughout the golgi.
Components of the SER?
-Does not contain ribosomes.
Primarily serves as a central packaging and discharge site for molecules to be transported to the ER.
-Sends molecules to transport vesicles where they can be distributed.
What are vesicles?
Cargo containers
What is the main purpose of the SER?
Lipid Synthesis
What is the SER in muscle cells?
The Sarcoplasmic Reticulum which stores calcium.
What is the Golgi complex?
The golgi complex is composed of stacks that bind with vesicles, sort and transport molecules appropriately.
–>Raw materials are turned into finished products and sorted accordingly. Each product is marked with a docking marker to ensure it gets sorted correctly.
Define exocytosis?
The mechanism of extruding substances to the cell’s exterior.
“Secretion of contents”
Where do secretory vesicles bind to cells?
ONLY to the plasma membrane and not into the actual cells internal membrane.
What are v-snares & t-snares?
After vesicles shed coating proteins, docking markers are exposed, which can bind with protein markers on the target membrane.
What are lysosomes?
Membrane enclosed sacs that contain powerful hydrolytic enzymes, capable of lysing and destroying cells.
- Form in the Golgi Complex
- Like a cell’s miniature digestive system
What is Phagocytosis?
- A type of endocytosis
- In taking of material by the cell by engulfing the foreign matter.
- ->Most commonly occurs in WBC’s.
What is Pinocytosis?
“Cell Drinking”
- A small droplet of extracellular fluid is internalized.
- The plasma membrane drips inward, which seals at the surface around the ECF contents.
What is the name of the protein responsible for pinching off Endocytotic vesicles?
Dynamin
Explain Receptor- Mediated Endocytosis?
- Intake of material by receptor- protein binding.
- Membrane sinks and seals at the surface.
- Highly selective, but allows intake of large molecules from the environment.
What are psuedopods?
- “False Feet”
- Surround the material to be engulfed and trap it within an internalized vesicle.
- ->Lysosomes then bind with the vesicle and break down the foreign matter.
What is the name of Selective Digestion?
-Autophagy
What is Tay-Saach’s Disease?
-Abnormal accumulation of of complex molecules formed in nerve cells.
What are peroxisomes?
- House oxidative enzymes
- ->Use oxygen to strip hydrogen
- ->help detoxify waste within cells.
- Major product is H202.
What does catalase do?
-Turns harmful H2O2 into H20 and CO2 from the oxidative enzymes.
Mitochondria Recap.
“Powerhouse of the Cell”
Produces 90% of the cell’s energy
-Contains both a smooth outer membrane and a folded inner membrane (cristae), with a fluid matrix.
*Cristae contains proteins that turns food into useable energy (metabolism)
–>Majority of metabolic processes occur in the matrix!
Glycolysis Recap.
- Turns glucose into 2 pyruvate
- Happens in the cytosol.
- Takes 10 reactions to do so.
- ->Produces 2 ATP/ glucose.
TCA Recap.
- Pyruvate is converted into 2 Acetyl CoA by the Pyruvate Dehydrogenase complex.
- Produces energy rich molecules ATP, NADH (2 ATP) and FADH2 (1 ATP)
Electron Transport Chain Recap
High energy electrons are extracted from NADH and FADH2.
–> Move along the assembly line, and produce cumulatively 30 ATP.
Oxidative Phosphorylation
-Occurs when oxygen is present.
–>Produces 36 ATP.
Starts in cytosol and ends in the matrix.
Substrate-Level Phosphorylation
- Occurs when no oxygen is present.
- ->Produces 2 ATP/ glucose (Less effective)
- Can’t proceed beyond glycolysis.
- Pyruvic acid is turned into lactic acid.
What are vaults?
-Shaped like octagonal barrels
-Hollow interior
Function: MIGHT be used to transport mRNA
-Nucleus to cytoplasm transporters of RNA
What is Cytosol?
55% of cell volume
- ->Gel like fluid
- Surrounds organelles
What is inclusions?
-Non-permanent storage houses for fat, glycogen and secretory vesicles in the cytosol.
What are the 2 houses for Fat storage?
Adipose tissue (fat droplets) and glycogen (liver and muscle)
What are Microtubules?
- Hollow tubules composed of protein TUBULIN.
- Determine cell shape and function
- Important for spindle formation during mitosis!
- ->Make up cilia and flagella.
What is Mitotic Spindle?
-Assembled from microtubules only during cell division, and are assembled from centrioles.
What are Microfilaments?
- Smallest elements of the cytoskeleton
- –>Composed of ACTIN.
- Vital for contractile systems.
- Important in motility, especially for pseudopods “false feet” in amoebas.
What are Intermediate Filaments?
- “Middle size”
- Form tough, durable fibres.
- Resist mechanical forces/ strain.
What makes up DNA?
-A deoxyribose sugar, a nucleotide base and a negative phosphate backbone.
A-T C-G
2 Main Functions of DNA
- amino acid synthesis
- synthesizing polypeptides
What is a gene?
- A stretch of DNA that codes for the synthesis of a particular protein
- -Found in chromosomes.
How many chromosomes do somatic cells contain?
-46 (23 pairs)
How many chromosomes do germ cells (gamates) contain?
Only 1 member of each homologous pair (23)
What is the function of histone proteins?
-Key role in packaging DNA into chromosomal structure.
What is the function of non-histone proteins?
-Gene regulation.
What makes up condensed chromatin?
-Histones + DNA + Non-Histones
DNA Replication Recap.
-Double stranded DNA unzips by helicase, and complimentary base pairing occurs on these strands. Creates new templates.
Semi Conservative Process
(One old, one new)
Transcription/ Translation Recap.
RNA serves as a “go-between” for DNA sequenced in the nucleus and protein synthesis in ribosomes.
- RNA is produced in the nucleus, and exits through nuclear pores into the cytosol where ribosomes are present as mRNA!
- mRNA carries the blueprint message.
- Once on the ribosome, tRNA puts the nucleotides into amino acid chains.
- DNA–> RNA–> Protein
Mitosis Recap.
-Daughter cells receive an identical, double strand of DNA.
*In multi cellular organisms, mitosis is used for growth and development.
Includes interphase, metaphase, anaphase, telophase (cytokinesis)
Meiosis Recap.
-Cell division of the gonads.
-Produces 4 gamates (daughter cells)
Each gamate contains a single strand of DNA.
–>2 cell divisions in meiosis
-Meiosis 1 includes chromosomal crossing over, which leads to genetic variation.
-In meiosis 2, the 23 chromosomes line up and and separate at the end of the spindles.
–>Sperms and Eggs are haploid.
