life @ cellular level - cells & molecules Flashcards
(29 cards)
What are stem cells?
Cells that can differentiate into many cells types (multipotent) or any cell type (pluripotent) of the body.
what is apoptosis?
Apoptosis is controlled, programmed cell death. It is a normal process
What is Necrosis?
Necrosis is the untimely death of cells in response to injury or infection. It is not a normal process.
What is cancer?
Cancer is uncontrollable cell division and proliferation which fails to coordinate with normal cells and fails to differentiate into specialized cells.
what is a nucleus?
contains DNA, associated with RER
site of ribosomal RNA synthesis and assembly
what is the cell membrane?
phosphlipid layer
selectively permeable barrier
embedded proteins act as receptors to detect chemicals and signalling molecules in ECF
what is a cytoskeleton?
maintains cell shape
microfilaments - actin (7nm)
intermediate filaments - keratin (8-12nm)
microtubules - tubulin (25nm)
what are cilia (supported by cytoskeleton)?
short hair-like projections that move with stiff power stroke and flexible recovery stroke
made of microtubules
what are flagella (supported by cytoskeleton)?
long whip-like protein structures that permit snake-like movement
made of 9 pairs of microtubules surrounding a central pair like cilia
what are RER and SER?
RER - has ribosomes which synthesis proteins and modifies them
SER - no ribosomes, produces lipids and steroid hormones. Metabolises toxins
what is the golgi apparatus?
packages proteins for transport
what is mitochondria?
has phospholipid bilayer
outer membrane has pores
inner membrane has cristae (folds)
matrix holds enzymes needed for metabolising food
has own circular DNA and synthesises own ribosomes
can self replicate
what are lysosomes?
membrane bound vesicles containing enzymes
used in autophagy (digestion of cells own material) and digestion of engulfed particles
what are peroxisomes?
enzymes that degrade long fatty acid chains
generate toxic hydrogen peroxide and breaks it to protect cell
what is chemical polarity?
unequal electron distribution
difference in electronegativity (atom’s attraction for the electrons in a bond)
what are 2 configurations of carbon molecules?
asymmetrical (chiral)
L- (laevo) - amino acids
D- (dextro) - monosaccharides
symmetrical (achiral)
give an example of why configuration is biologically important (rhodopsin)
Rhodopsin is a protein embedded in the retina of the eye.
light exposure causes the configuration of rhodopsin to alter stimulating nerve cells in the optic nerve
send messages to the brain where we see.
what is oxidation and reduction?
oxidisation - chemical reaction where electrons are lost, gain of +’ve charge
reduction - chemical reaction where electrons are gained, -
-‘ve charge
what is a oxidising and reducing agent?
oxidising agent - becomes reduced itself as it oxidises
reducing agent - becomes oxidies itself as it reduces
what is the oxidising and reducing agent in redox reaction of glucose into lactate?
NAD+ is being reduced to NADH (it has gained electrons) thus it is the oxidizing agent, it oxidizes other compounds, takes electrons from them.
NADH is being oxidized to NAD+ (it has lost electrons) thus it is the reducing agent, it reduces other compounds, it gives them electrons.
what is a dehydrogenation reaction?
A chemical reaction where hydrogen atoms are transferred from one molecule to another
what is a condensation reaction?
A reaction where two smaller molecules combine to form a larger molecules
releases water (or other small molecules e.g. methanol)
which of the 5 bases are pyrimidines and purines?
pyrimidines - CTU
purines - AG
what is a hydrolysis reaction?
A reaction that adds water to a molecule, and simultaneously breaking down a larger molecule into smaller units
