UNIT 2 - B 2.2 - Organelles and Compartmentalization Flashcards
What is cell compartmentalization?
The isolation of reactions so they don’t interfere with one another
What is the result of cell compartmentalization?
cells work much more efficiently
What is reductionism?
Studying cells by breaking them down into individual components
What does fractionation refer to in biochemical fractionation?
the separation and isolation of spedivid chemicals/structures so detailed research can be carried out
What is another word for cell fractionation?
Centrifugation
What does centrifugation allow?
the extraction of organelles from the cell
What is the process of cell fractionation?
cells are mixed in a tube with substances that break down the cell membranes, the sample is spun in an ultracentrifuge to isolate the different components, larger/heavier components go to the bottom of the tube and seperate at lower speeds
What technique is effective in isolating pure substances such as amino acids, proteins, carbohydrates, and plant pigmants?
chromatography
What is the process of chromatography?
A mixture of molecules is placed in a separating medium, and the molecules seperate depending on size and speed they travel through the medium
How does gel electrophoresis separate molecules?
by passing them through a gel using an electric charge
What are molecules separated based on with gel electrophoresis?
size and charge
Why are barriers around organelles important?
It allows the chemical reactions in an organelle to not be interfered with from the rest of the cell
What components of cells are not organelles?
cell wall, cytoskeleton, and cytoplasm
What components of cells are considered organelles?
nucleus, vesicles, ribosomes, plasma membrane, cilia/flagella, golgi apparatus, mitochondria, chloroplasts, and lysosomes
What are the processes responsible for the production of proteins called?
transcription and translation
What is involved in transcription?
a DNA strand acts as a template for the formation of mRNA
What is involved in translation?
Ribosomes use the code from the mRNA to produce polypeptide chains
Where does transcription occur?
the nucleus of eukaryotic cells
Where does translation occur?
in the cytoplasm
What does the seperation of transcription and translation allow?
post-transcriptional modifications of mRNA to occur in the nucleus before translation occurs in the cytoplasm
How does the transcription/translation process differ in prokayotic cells?
The two processes are not isolated so mRNA can come into contact with ribosomes and start translation immediately without any modifications
What does the number and size of organelles depend on?
the overall function of the cell in which they occur
What do acinar cells specialize in?
The secretion of digestive enzymes
Which organelles are greatly enlarged in acinar cells?
the ER, golgi apparatus and granule storage compartments
What does keeping reactions separate in different parts of the cell result in?
The metabolites and enzymes for each process and be concentrated in a particular area
What does the metabolites and enzymes being concentrated in a particular area allow?
That pathways run smoothly, can be easily controlled, and do not interfere with one another
What do lysosomes help do?
breakdown wastes and cellular components that need to be replaced
What would happen if the enzymes involved with the waste breakdown in lysosomes weren’t isolated by a membrane?
They could cause severe damage to the cell
What is often the result of endocytosis?
a phagocytic vacuole
What happens after the phagocytic vacuole comes into contact with a lysosome?
inactivation and digestion of the threatening contents of the vacuole
What does phagocytosis help defend the cell against?
invading phathogens
What must happen due to the cell having organelles carrying out one specific function?
They have to develop a means of integrating each separate function
How are some of the separate functions integrated?
Some organelles are connected in a functional series allowing chemical pathways to take place
Why have membrane pumps and carriers evolved?
So that the products of one organelle can enter another and important cell reactions can occur
What is cell respiration?
The process by which glucose is used to produce ATP which then provides energy needed for cell reactions
Where does respiration (the complex chemical reactions) mostly occur?
In the mitochondrion
Why do all organisms carry out respiration?
All organisms must be able to produce ATP for energy
What is the outer mitochondrial membrane?
A membrane that separates the contents of the mitochondrion from the rest of the cell
What is the matrix of the mitochondrion?
a cytoplasm-like substance inside the mitochondrion that contains enzymes for the first stages of respiration to take place in the mitochondrion
What is the cristae of the mitochondrion?
Tubular regions around the membrane the increases surface area for reactions to take place towards the end of respiration
What is the inner mitochondrial membrane?
A membrane containing the carriers and enzymes for the final stages of respiration
What is the space between the inner and outer membranes of the mitochondrion?
A reservoir for hydrogen ions/protons allowing for a high concentration of protons
What may mitochondrial defects in children lead to?
Muscle weakness and it could affect mental development
Where do all the steps in photosynthesis occur?
Inside the chloroplast
Where does chloroplasts occur?
Mostly in leaves, some plants have them in the cells of other organs
Why are chemical bonds made in photosynthesis?
to produce carbon compounds
What are the raw materials of photosynthesis?
carbon dioxide and water, light providing energy
What are involved in photosynthesis to enable the formation of glucose, more water, and oxygen?
enzymes
What is photosynthesis essentially the reverse of?
Respiration
What kind of process is respiration?
catabolic
What kind of process is photosynthesis?
anabolic
What are the organisms called in which photosynthesis occurs?
autotrophs
What are autotrophs?
An organism that can produce their own food
What allows for the anabolic reactions to happen efficiently (photosynthesis)?
The structure of chloroplasts
What does the extensive membrane surface area of the thylakoids in chloroplasts allow for?
Greater absorption of light by photosynthesis
What do the small space (lumen) and low volume of fluid within the thylakoids in chloroplasts allow for?
Faster accumulation of protons to create a concentration gradient
What does the stroma region (similar to cytoplasm) in chloroplasts allow for?
it provided a region where the enzymes for the Calvin cycle can work
What does the chloroplasts’ double membrane allow for?
isolating the working parts and enzymes of the chloroplast from the surrounding cytoplasm
What does the nuclear envelope provide?
an area where DNA can carry out its functions without being affected by processes occuring in other parts of the cell
What do the pores through the nuclear envelope allow?
Ions and small molecules to diffuse between the nucleoplasm and the cytoplasm
What is the nucleoplasm?
nuclear material
What do the pores in the nucleus control the passage of?
mRNA, proteins, and RNA-protein complexes into and out of the nucleus
Where are ribosomes produced?
in the nucleolus
What must mRNA do to be transcribed?
leave the nucleus
What is continuous with the outer membrane of the nuclear envelope?
The ER of the cytoplasm
What are some similarities between the outer membrane of the nuclear envelope and the ER?
ribosomes are seen attached toboth and they can also both form vesicles
What does the inner membrane of the nuclear envelope interact with?
chromatin
What happens early in both mitosis and meiosis allowing for the movement of the DNA structures?
the nuclear membrane breaks down
What does the nuclear membrane become after breaking down for mitosis/meiosis?
vesicles circulating in the cytoplasm
What happens with the vesicles at the end of mitosis and meiosis?
they attach to the surface of the condensed chromosomes and eventually reform the nuclear envelope
What are ribosomes made out of?
proteins and rRNA
What do the specialized attachment sites on ribosomes’ two subunits allow?
multiple amino acids to be bonded into highly specific proteins
Where may ribosomes be found in eukaryotic cells?
on the rough ER or free floating in the cytoplasm
What kind of proteins do free ribosomes produce?
proteins that are used within the cell such as in the cytoskeleton
Where are the proteins produced by ribosomes on the rough ER used?
in the nucleus, mitochondria, and in others
What happens with proteins produced by ribosomes bound to membranes?
they are transported through the ER and are often exported from the cell
What are secretory proteins produced by?
membrane-bound ribosomes
What happens with secretory proteins?
They are sent to the golgi apparatus where they are packaged for cellular exit
What are two examples of secretory proteins?
hormones and enzymes
Which kind of cells typically have numerous sacs for the golgi apparatus?
Cells involved in producing and secreting substances
What are the stacks of flattened sacs in the golgia apparatus called?
cisternae
Which side of the golgi apparatus is the cis side?
the side close to the ER
Which side of the golgi apparatus is the trans side?
the side directed towards the plasma membrane
Which side of the golgi apparatus are protein or lipid-filled transport vesicles recieved on?
the cis side
Why are the proteins or lipids modified as they move through the golgi apparatus?
so that they can carry out the specific function needed at that time
When is the modified protein or lipid sent to the trans side of the golgi apparatus?
After they are packaged into vesicles
What is often attached to the substance in the modification process in the golgi apparatus?
a signal chemical that directs the destination of the product
After moving through the trans side of the golgi apparatus, what are some examples of what happens with the vesicles?
they may become lysosomes, they may return to the ER and they may leave the cell through exocytosis
What are examples of vesicles?
peroxisomes, lysosomes, transport vesicles, and secretory vesicles
What is contained in peroxisomes?
enzymes used to break down fatty acids
What are contained in lysosomes?
enzymes for cellular digestion and for destroying defective/damaged organelles
What do transport vesicles do?
move molecules within the cell
What do secretory vesicles contain?
materials to be excreted from the cell such as neurotransmitters and hormones
What are clathrins?
proteins in the cell membrane that anchor certain proteins to specific sites
Where do clathrin proteins especially occur?
on the exterior plasma membrane in receptor-mediated endocytosis
Why does clathrin proteins line coated pits?
to allow receptors to bind to specific molecules
What happens when an appropriate collection of molecules occurs in the clathrin-lined pit?
The pit deepens and will eventually seal off forming a vesicle
