Cell Structure Flashcards
How do proteins know where they are supposed to go in the cell?
They have built in postal codes within their amino acid sequence
Hydrophobic amino acids go to?
The endomembrane
Charged amino acids go to?
The mitochondria
No signalling sequence amino acids go to?
The cytosol
The path from signal in the amino acid to protein
The signal sequence gets recognized by another protein, which guides the ribosome to the rough ER. The protein will then be made through the RER membrane into the ER lumen
The endomembrane system is comprised of? (NEGLVVP)
- Nuclear envelope
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Vesicles and vacuoles
- Plasma membrane
What are the functions of the endomembrane system? (STMMD)
- Protein synthesis
- Protein transport
- Metabolism
- Mouvement of lipids
- Detoxifying the cell
What is the endoplasmic reticulum?
The flattened membrane sacks called cisternae
What is the ER lumen?
The space between ER membranes
What is the rough ER studded with?
Ribosomes
What does the rough ER produce?
Glycoproteins, phospholipids, and other proteins
What does the rough ER do?
Separates and transports proteins out by transport vesicles
The smooth ER lacks?
Ribosomes
What does the smooth ER produce?
Lipids
What does the smooth ER do?
- Detoxyfies the cell - adds hydroxyl groups to drugs
- Storage of calcium ions -triggers muscle contractions
- Metabolises carbs
What is the Golgi Apparatus?
A series of flattened sacs called cisternae
What side of the golgi does the Cis side face?
The rough ER (the receiving end)
What side of the golgi does the trans side face?
Points out towards the rest of the cell (shipping end)
Vesicles bring material from the (blank) to the (blank), fusing with the Golgi membrane
(rough ER), (Cis face)
Vesicles pinch off of the (blank) and head to their final destination within or outside of the cell
Trans face
What is the lysosome made up of?
Membranous sac of hydrolytic enzymes
What does the lysosome do?
Breaks down macromolecules into monomers
Why aren’t the contents of a lysosome digested if it ruptures?
Because the cytosol pH is too high for the enzymes
What are the types of intracellular digestion?
Phagocytosis
Autophagy
How do white blood cells use phagocytosis?
To kill bacteria and other invadors
What is autophagy? (“self eating”)
Damaged organelles get surrounded by a magic double membrane
It merges with a lysosome which digests the materials
Monomers and molecules are recycled by the cell
What is phagocytosis?
Happens in amoebas and other unicellular eukaryotes.
When a food vacuole merges with a lysosome. Digestive enzymes break down the food molecules into monomers
Lacking lysosomal enzymes can result in rare genetic disorders such as?
Tay-Sachs disease: the brain becomes impaired due to too much lipids in the cells
What is the vacuole made from?
The rough ER and Golgi apparatus
What types of vacuoles are there? (FCPC)
Food and digestive
Contractile vacuole- pumps out excess water from freshwater
Plant vacuole- storage for small molecules, some hydrolosis of molecules
Large central vacuole- contains inorganic ions and swells up due to osmosis
How does turgor pressure affect plants?
It allows plants to stand upright against gravity, which is essential for plant growth
What does the mitochondria do?
The site of cellular respiration - energy is converted to ATP, energy is stored in high energy P-P bonds
Does the mitochondria have its own DNA?
Yes
Can the mitochondria self replicate?
Yes
Chloroplasts are a type of?
Plastid
Chloroplasts are only found in?
Plants and Algae
Chloroplasts absorbs (blank) from (blank) and converts (blank) into (blank)
(energy, photons, energy, ATP)
What are Heterotrophs?
An organism that obtains its energy through consuming material
What are Autotrophs?
Organisms that obtain their energy by themselves
What are Anaerobes?
Organisms that can’t survive in O2 and can’t usr O2 to extract energy from molecules
What are Aerobes?
Organisms that can survive in O2 and that can use O2 to extract energy from molecules
What does the endosymbiont theory describe?
How mitochondria arose
What is the endosymbiont theory?
A eukaryotic cell engulfed an aerobic heterotrophic prokaryotic cell that could use oxygen. The prokaryote was retained and became the mitochondria
What evidence supports the endosymbiont theory?
Mitochondria are double membraned
Contain their own set of DNA and ribosomes
Able to grow and reproduce in the cell
What’s the advantage for having both chloroplasts and mitochondria?
Chloroplasts convert light energy into chemical energy, and mitochondria consume the chemical energy to produce ATP
Essential for plant growth!!!
What is the mitochondria made of?
Two membranes
an intermembrane space in between
When the inner membrane folds, it makes?
Cristae
What does cristae do?
Increase the surface area of the mitochondrial membrane.
What does the inner membrane of the mitochondria contain?
DNA and ribosomes
What is the function of the mitochondria?
Cellular respiration
What is the mitochondria size range?
1-10um
What does the chloroplast consist of?
Two membranes with intermembrane space in between
Where is DNA and ribosomes contained in the chloroplast?
The stroma
What is the function of a chloroplast?
Photosynthesis (creation of energy)
When the inner membrane of the chloroplast folds, it makes?
Thylakoids which are stacked to form grana
What are peroxisomes?
A specialized metabolic organelle that produces hydrogen peroxide
Chloroplast size?
3-6um
What does chloroplast contain other than DNA and ribosomes?
Chlorophyll (makes plants green)
What do peroxisomes contain?
Enzymes that produce hydrogen peroxide
The peroxides can be used to do what?
Use oxygen to break down fatty acids, or transport to the mitochondrion
Used in fuel during cellular respiration
Detoxifies alcohols in the liver
Plants have a specialized peroxisome called?
Glyoxysome (converts fatty acids to sugars during seed germinaton)
