Intro to cell/Physiology lecture 4 Flashcards
Most cells have a nucleus that is surrounded by a membrane and contains…
..a copy of our DNA/chromosomes (half from mom/half from dad) and nucleolus (site of very active DNA).
What makes up the wall of the nucleus?
2 phospholipid bilayers
Nuclear pores
Easy for things to leave the nucleus through pores.
Difficult for things to come into the nucleus.
Why is it difficult to get things into the nucleus?
You don’t want something coming in (ex: virus) and re-writing or inhibiting DNA
Nucleoplasm
Fluid inside nucleus
Cytoplasm
Fluid outside nucleus
Endoplasmic Reticulum (E.R.)
Double walled structure surrounding nucleus
(looks like coral or sponge)
Stores Ca++ inside
Function of E.R.
Protect nucleus and DNA
“Make things”
2 types of E.R.:
Agranular E.R. (smooth)
Granular E.R. (rough)
Agranular E.R.
Smooth
lipid formation
Granular E.R.
Rough
Protein formation
Ribosomes site on surface
Ribosomes
The machines that create protein
Steps of protein formation (gene to protein)
- Gene must be read (transcription)
- Message must be created (RNA) (transcription)
- RNA sent to granular E.R.
- Message decoded by ribosomes (translation)
- Amino acids are used to make protein
Transcription
The process of reading DNA and forming RNA
Translation
The process ribosomes use to turn RNA message into protein
Amino acids used to from protein:
Alanine Cysteine Histidine Phenylalanine Serine Proline
Intracellular concentration of AA:
Higher than outside cell
Golgi Apparatus
Place where protein modification occurs
Transport vesicles
Transport proteins from E.R. to golgi apparatus
Secretory vesicles
Transport proteins from golgi apparatus to where they need to be
Lysosomes
Use hydrolysis to break things up (unneeded lipids, dysfunctional proteins)
Hydrolysis
Enzyme splits H2O and puts the H+ on one molecule, then puts OH on another molecule, breaking apart the structure (see lecture 4 at 0:42:50)
Lysosomes need what kind of pH to operate?
Acidic
Where do Lysosomes originate from?
Golgi apparatus
Peroxisome
Use oxidation to break things up (dysfunctional structures, structures in excess, bacteria/virus)
Oxidation
Uses H2O2
Catalase
Enzyme found in peroxisomes. It controls the rate of production/loss of H2O2
Hydrolase
Enzyme found in Lysosomes
Mitocondria
Produces ATP (requires oxygen)
For every 1 molecule of glucose the cell takes in, what is the net total of ATP produced?
38 ATP
Glycolysis produces..
2 ATP and 2 pyruvic acid (doesn’t require oxygen)
Pyruvic acid can be turned into..
Acetyl- CoA
Acetyl- CoA
Used to build stuff (ex: cholesterol) and is an important energy compound
Citric acid cycle
Uses Acetyl-CoA to produce multiple things including 2 ATP. (requires oxygen)
Where do mitochondria and peroxisomes come from?
They are capable of self replicating
What determines the number of mitochondria in a cell?
The metabolic requirements of the cell. (more if cell is very active, less if cell is dormant)
DNA in mitocondria
Have their own set
about 30 DNA
all comes from mother
Free floating ribosomes
About 10% of ribosomes are floating in cytoplasm. They can produce proteins but are not the main source.
HIV
HIV uses an enzyme called “reverse transcriptase” to work backwards. It uses RNA to rewrite DNA
Insulin example of protein making precess
Proinsulin gene –> golgi apparatus –> CPeptide and Insulin
The carbs on the outside of cells attract..
cations, which contribute to the positive gradient outside and negative gradient inside cell (electrogenic)
How does Na+K+ pumps function as a “cell diuretic”
If the pump slows down Na+ isn’t being pumped from cell as quickly causing increase in Na+. This causes an increase in osmolarity and more water comes into the cell to try and dilute the Na+
VMax
Transporter proteins in facilitated diffusion are saturated and transporting as fast as possible
