1.2 Cell structure Flashcards
What is the cytoskeleton? What makes it?
interconnected network of fibrous and tubular proteins, linked together in chains like an internal skeleton 3 types: Microfilaments Intermediate Filaments Microtubules
What is a centrosome?
central cytoskeleton organization centers, where microtubules originate
located next to nucleus
microtubules
What is a centriole?
short, cylindrical microtubule structures
located IN centrosome, next to nucleus
used in cell division to hold onto and move DNA/chromosomes
microtubules
What is a lysosome?
Lysosomes are “digestive garbage cans”
Structure:
membrane enclosed, spherical shape, filled with harsh, degradative, digesting enzymes
Molecular breakdown:
engulf worn out cellular material and pathogens via phagocytosis
about 40 different hydrolytic enzymes break down cell debris, organic molecules, bacteria, pathogens
What is a peroxisome?
Peroxisomes are cell detoxifiers
Structure:
membrane enclosed, spherical shape, filled with oxidative enzymes
Antioxidant Detoxification:
concentrate and break down fatty acids and other molecules, breakdown hydrogen peroxide (H2O2 “free radicals”) to prevent cell damage
uses oxidative enzymes to breakdown other harmful molecules such as alcohol, toxins
What is a proteasome?
Proteasomes are protein breakdown and digesting centers, also digestive “garbage cans”, but smaller
Structure:
ring-like stack of enzymes that takes in proteins and breaks them down
Protein Clean Up:
uses enzymes to concentrate and break down denatured, old, abnormal, or damaged proteins
important in immune response to break down viral proteins in infected cells
What happens if there is insufficient O2 for cellular respiration?
Oxygen deprivation to cells: this is the important reaction. Without oxygen, mitochondria cannot do cellular respiration.
Ischemia—> 1st, no cellular respiration —> ATP production ceases —> badness
What is the pathophys of lysosomes?
high levels in macrophages for pathogen and cellular debris breakdown
Autolysis, important role in cell death, lysosome membrane broken down, releases digestive enzymes into the cytoplasm
protective to remove damaged cells
part of development to prune and modify tissues and structures
pathological response to oxygen deprivation, etc.
What happens with lysosomal storage diseases? What is an example?
altered function can lead to accumulation of cellular metabolites
ex: Tay Sach’s Disease: neurological disease due to accumulation of lipid gangliosides- seizures, vision loss, paralysis, intellectual disability, death in early childhood
What is the pathophys of mitochondria?
sensitive to oxidative stress and nutrient depletion
can trigger lysosome-mediated autolysis
multiple classes of genetically linked mitochondrial diseases, maternal inheritence, includes some neurodegenerative, cardiovascular, movement and sensation disorders
What is the pathophys of DNA damage? Where can this damage occur?
within the nucleus or within mitochondria
errors in DNA replication
generation of free radicals
UV Radiation
genotoxic agents: multiple types of DNA damaging molecules
can lead to cancer if cell death pathway is not responsive
explains some genetic links to cancer due to mutations in DNA repair pathways
What is the structure of the plasma membrane?
phospholipid bi-layer
proteins
cholesterol- embedded in phospholipids
carbohydrates
What is a glycoprotein? Generally speaking, what do they do?
combination of carbohydrates and proteins on the surface of a cell
cell type and identification markers
used by the immune system to recognize self vs. other
example: blood type markers, cell surface markers on bacteria or other pathogens
What is a cotransporter?
similar to channels, highly selective, but require other molecules as “trade” for the molecule that is being transported (ex: Glucose/Na+ cotransporter, swaps glucose IN for Na+ OUT)
What is secondary active transport? What are the two kinds?
Active transport with a cotransporter. (requires ATP)
Symport- “Piggyback” both molecules go the same way
Antiport- Molecules go opposite ways
