Carla - The Cell Flashcards
List the ten most important organelles in the cell
Nucleus
Nucleolus
Chromatin
Golgi Apparatus
Endoplasmic Recticulum
Ribosomes
Vacuoles
Lysosomes
Mitochondrion
Cytoplasm
How does mRNA leave the nucleus?
Through the nuclear pores
What happens after mRNA leaves the nucleas?
It moves to the ribosome where it forms a chain of amino acids
List the eight structural components of a mitochondrion
Outer membrane
Inner membrane
Intermembrane space
Cristae
Matrix
Granules
Ribosomes
DNA
What does the mitochondrion do?
Performs cellular respiration
What is cellular respiration?
The breakdown of food into energy the body can use (ATP)
What is the main theory on the origin of the mitochondrion?
They are believe to have been prokaryotes that formed a symbiotic relationship with humans
Why is it theorised that mitochondria were once prokaryotes?
They have their own DNA and can undergo some processes on its own
What are the cristae of a mitochondrion?
Folds in the inner membrane
What are the two types of endoplasmic recticulum?
Smooth and rough
What is the main differnce between smooth and rough ER?
Rough ER has a lot of ribosomes while smooth ER has very little
Why does rough ER have so many ribosomes?
Rough ER is where many proteins are made
What is the main function of smooth ER?
It packages up newly synthesised proteins (from the rough ER) and ships them off to the Golgi apparatus
What is the main function of ribosomes?
This is where translation occurs
What is the Golgi Apparatus often called?
The protein delivery centre
What happens to proteins in the GA?
Modifications to proteins can be made here e.g. groups can be added on e.g. phosphorylation
What happens to proteins after they have been modified in the GA?
They are transported through the vesicles in the GA and then floated out into the cytoplasm
What happens to proteins after they have left the GA?
They are either used within the cell or they undergo exocytosis
What is exocytosis?
This is where molecules such as proteins contained within a vesicle are spat out of the cell
Where in the cell is the GA located?
Usually found beside or close by the ER in order to organise proteins efficiently
What are the two faces of the GA
The cis and trans face
What does the CIS face of the GA do?
It accepts proteins from the ER and organises them
What does the trans face of the ER do?
It ships proteins out to where they are needed in vesicles
How does the GA form vesicles?
By pinching off parts of it’s membrane
What is found inside the lysosome?
Hydrolytic enzymes
What is found on the outside of the lysosome?
Transport proteins
What is the lysosome often called in relation to it’s function in the cell?
The stomach of the cell
List some of the functinos of the lysosome
Help destroy invading pathogens
Apoptosis
What is the pH inside the lysosome?
pH 5
What is the pH inside the cell?
pH 7
Why do the enzymes found inside the lysosome only work at pH 5?
This is a safety mechanism to prevent unintentional damage to the cell
How are lysosomes used to treat cancer?
Lysosomes are involved in apoptosis - trying to find a way of triggering this in cancer cells
What is the plasma membrane made up of?
A phospholipid bilayer (phosphate head and hydrophobic tail)
Describe the structure of the phospholipd bilayer
The hydrophobic tails hide away in the middle
The hydrophilic heads face the inside of the cell and the extracellular liquid
What is meant be the fluid mosaic model
The bilayer can be squished and pressed in a way that resembles a liquid mosaic
List some of the different plamsa membrane proteins
(4)
Intrinsic proteins
Extrinsic proteins
Channel proteins
Ion channel proteins
How do intrinsic and extrinsic proteins differ from one another?
Intrinsic proteins run from one side to the other
Extrinsic proteins don’t run from one side completely to the other
What is a ligand?
A message
How does cell signalling work?
There is constant cross talk between cells
A ligan is picked up by a receptor on a cell
The ligand binds to the receptor, causing a conformational change in the receptor and activating it
A chain reaction then occurs in the cell for the response to occur
Why is it dangerous for a cell to pick up an irrelevant ligand?
If a cell picks up a growth ligand meant for another cell this can result in the growth of a tumour (cancer)
What is signal transduction?
The signal is converted from one physical form to another
What are the five types of cell signalling?
Endocrine
Paracrine
Neuronal
Contact-dependent
Autocrine
Write a note on endocrine cell signalling?
(4)
They utilise hormones
They work over long distances
Endocrine cell produces a hormone which enters the bloodstream to reach a target cell where it binds to a receptor
e.g. growth hormone
Write a note on paracrine cell signalling
(5)
Work in a local vicinity
A signalling cell targets a nearby cell (target cell)
Local coordination
Ligands diffuse between the cells through the extracellular fluid
Very important in development
Write a note on neuronal cell signal
(5)
Neuronal-synaptic signalling
Work over very short distances
Nerve cell signals
Synapse-neurotransmitters
quickly degraded or taken back in to reset (to prevent incorrect firing such as in epilepsy)
Write a note on contact-dependent cell signalling
(4)
Cell-cell contact signalling
Neighbouring cells
Gap junctions (tiny channels that fit in between cells with extracellular fluid found between)
Intracellular mediators
Write a note on autocrine signalling
Note to self
Important in development
Helps cells take on their identity and keep it
Give four responses to signals
Survive
Divide
Differentiate
Die
