6 - Cell Structures & Function Flashcards
chapter 7
The nuclear envelope, what is it’s purpose? And is it single membrane, or double?
encloses the nucleus
Double membrane
What is stored in the nucleus?
Chromosomes & information storage
Define the nuclear lamina
it is the fibrous protein shell - strengthens the structure and maintains it’s shape
on the interior chromosomes attach to it
What is in the nucleolus?
Where RNA molecules found in ribosomes are made + small and large ribosomal subunits are made
What is the endoplasmic reticulum?
“inside formed network”
it extends from the nuclear envelope into the cytoplasm
What is different between the rough endoplasmic reticulum and the smooth endoplasmic reticulum?
rough ER - purpose is to synthesize proteins
smooth ER - purpose is to catalyze reactions involving lipids
Describe what the rough endoplasmic reticulum does
makes proteins for - plasma membrane, secreted into the cell exterior, or shipped to an organelle
the ribosomes on the exterior manufacture the proteins the then move inside on the lumen to undergo folding
What are the functions of some of the proteins produced by the rough ER?
- carry messages out to other cells
- act as membrane transport proteins or pumps
- enzymes
Rough ER products are packaged up and shipped out
The smooth endoplasmic reticulum - what is the purpose?
- contains enzymes that catalyze reactions w/ lipids
- could break down lipids
- manufacturing site for phospholipids used in plasma membranes
- reservoir for calcium ions that act as signaling
What is the purpose of the cytoskeleton?
to hold the shape
long polymers of globular proteins
What is the most prominent cell in bacteria?
Chromosome
What is the purpose of ribosomes?
to manufacture proteins
Describe a periosome
single membrane originates from the ER contains transporters for macromolecules Function: oxidizes FA (H2O2) Said to contain: catalase
Describe the Golgi apparatus
for folding and finishing of proteins
cis side close to RER, receiver bay for Proteins from RER
trans surface -> plasma membrane, shipping bay
The smooth ER - describe
contains enzymes to catalyze lipids
manufacturing site for phospholipids -> cell membrane
Reservoir for CA ions
has no ribosomes
Describe glyoxysomes
in plants
oxidizes fats for storage
Describe Lysosomes
Single membrane contains protein pump maintains a pH of 5.0 acid hydrolases function: digestion & recycling -> monomers autophagy & phagocytosis
define phagocytosis
“eat cell act”
a membrane surrounded package delivers to the lysosome to breakdown contents
define autophagy
“same eating”
breaking down damaged organelles
Does the mitochondria have a single or double wall?
double
Which organelle carries it’s own chromosomes allowing it to make it’s own genes?
the mitochondria
What is the difference between the Prokaryote cell and a Eukaryote cell?
Procayote are small, not bound organelles, has some genetic material
Eukaryote can be 10-50 times bigger
Compartments allow for greater size
arganelles have various jobs
What is the difference between plants and animal cells?
Plants have a cell wall, not a plasma membrane
Power for plants is found in the chloroplast not the mitochondria
Plants have a vacuole - for storing
Define glycolipids
Lipids that contain a carbohydrate group
What is the neucleus enclosed in?
Nuclear envelope
What is contained within the nucleolus?
the neucleus
What is the main purpose of the ribosomes?
Produce proteins
What are the components of the endomembrane system?
golgi apparatus rough endoplasmic reticulum smooth endoplasmic reticulum Ribosmes lysosomes plasma membrane
define lumen
interior of a sac
What are nuclear pores?
Openings in the nuclear envelope
as well a connection site for the nucleus and cytosol
When proteins are being synthesized by a ribosome where are the three destinations
exported from the cell
to the cell membrane -> plasma membrane
lysosomes
Describe the secretory pathway hypothesis for a protein starting at a ribosome to ejection from the cell
The ribosome attaches to the RER -> proteins enters the lumen of the RER while being synthesised by the ribosome
Protein exits ER -> cis face of Golgi apparatus
Golgi - folds and finishes the protein
packages it up and ships out to plasm membrane
What crosses the nuclear envelope?
mRNA out
proteins in
What are the 5 steps to the signaling hypothesis
1 - Ribosome makes Protein into the Er with a signal sequence on it - PO
2 - Sequence binds to signal recognition particle (SRP) a complex of RNA & Protein
3 - Ribosome + signal sequence + SRP attaches to receptor in ER Membrane (acts as a key) => unlocks it
4 - once unlocked releases SRP
5 - signal sequence removed & protein synthesis complete
How does on know the synthesis of a mambane protein differs from one that will be exported?
it would be directly inserted into the membrane as it is being synthesized instead of fee floating in the lumen
When proteins enter the ER what is added?
glycosylation adds carbohydrate groups to proteins
what side of the Golgi apparatus is facing the RER
-cis
Which side of the Golgi apparatus faces away from the RER?
trans face
define endocytosis
general term for pinching off of the plasma membrane that results in the uptake of material from outside of the cell
Define exocytosis
secretion of intracellular molecules contained within membrane-bound vesicles, to the outside of the cell by fusion of the vesicles to the plasm membrane
contrasing endocytosis
Every protein that comes out of the Golgi has a molecular tag with a destination - Where are those three destinations?
Endoplasmic Reticulum
Plasma membrane
lysosomes
As a protein leaves the golgi and has no sequence with a PO - where does it go?
No where - cytoplasm
