Eukaryotic Cell: structure and function Flashcards
Facilitated transport can be differentiated from active transport, because active transport requires –
an energy source
The cell is the basic unit of function and reproduction, because sub cellular components cannot –
regenerate whole cells
Dialysis is based on a – membrane that mimics the cell membrane and has physical pores of a specified size and resembles the function of the cell membrane
semipermeable
glucose is a relatively large molecule and cannot freely diffuse through the plasma membrane but requires a – embedded in the membrane
transporter protein
diabetes results from the inhibited release of – to facilitate the uptake of glucose by the cell
insulin
T/F: water, small hydrophobic molecules, small ions, and neutral gas molecules can freely diffuse through the semipermeable membrane
true
A protein that has several regions that contain 20-25 hydrophobic amino acids would most likely be a – protein
integral
A membrane bound vesicle that contains hydrolytic enzymes is most likely a –
lysosome
lysosome is the digestive region of the cell and is a membrane bound organelle with a low pH around – that stores hydrolytic enzymes
5
vacuoles and vesicles are membrane bound sacs involved in the transport and – of materials that are ingested, secreted, processed or digested by cells
storage
chloroplasts are the site of photosynthesis and are found only in – and plant cell
algae
vacuoles are – than vesicles and are more likely to be found in plant cells
larger
chloroplasts contain their own – and – and may have evolved via endosymbiosis in like mitochondria
DNA and ribosomes
– are vesicles involved in the transport and storages of materials that are ingested by the cell through phagocytosis. The vesicles are formed by the fusion of the cell membrane around the particle
phagosomes
a phagosome is a cellular compartment in which – can be digested
pathogenic microorganisms
phagosomes fuse with lysosomes in their maturation process to form –
phagolysosomes
A DNA damage checkpoint arrests cells in – transition
G1/S
DNA damage checkpoint is a signal transduction pathway that blocks cell cycle progression in G1, G2, and metaphase and slows down the rate of – progression when DNA is damaged
S phase
G-C base pairs are linked by – hydrogen bonds
3
A-T base pairs are linked by – hydrogen bonds
2
Because of complimentary base-pairing, double-stranded DNA has equal quantities of G = C (and T = A)
Chargaff’s rule
Phospholipids contain a – backbone, a phosphate group and a simple organic molecule (choline)
glycerol
phospholipid tails are forced to aggregate via –
hydrophobic forces
phospholipid hydrophilic heads = glycerol and –
negatively charged phosphate group
phospholipid hydrophobic tails usually consists of 2 long – (saturated or unsaturated) hydrocarbon chains
fatty acid
– is embedded within the lipid bilayer in animals but absent in plant cell membranes
cholesterol
the overall shape of a cell is determined by its –
cytoskeleton
– is determined by the total concentration of dissolved particles in solution
osmolarity
compounds that dissociate into ions increase the concentration of particles and produce a – osmolarity
increase
to determine which molecule (after dissociation into ions) generates the highest osmolarity, determine the number of – each molecule dissociates into when dissolved in water
individual ions
the two ribosomal subunits are produced in the –
nucleolus
– are the site of protein production
ribosomes
prokaryotic ribosomes subunits
30S and 50S = 70S
eukaryotic ribosomes subunits
40S and 60S = 80S
Golgi apparatus ia a membrane-bound organelle that modifies (glycosylation), sorts, and – proteins
packages
rough ER is a portion of the endomembrane system that extends from the –
nuclear envelope
rough ER is the site of production and – of proteins
folding
misfolded proteins exit the rough ER and are sent to the – for degradation
proteosome
– are phosphorylated proteins responsible for specific events during cell division, such as microtubule formation and chromatin remodeling
cyclins
cyclins can be divided into four classes based on their behavior in the cell cycle: G1/S, S, – and G1 cyclins
M
p53 is a – gene
tumor suppressor
p53 or guardian of the genome plays a big role in conserving stability by preventing –
genome mutation
a codon is a 3-nt segment of an – that hybridizes (via complementary base pairing) with the appropriate anticodon on the tRNA to encode for one amino acid in a polypeptide chain during protein synthesis
mRNA
tRNA only interacts with the mRNA – the mRNA is bound to the ribosomal complex
after
operon regulates the – of genes into mRNA and is not involved in the translation of mRNA into proteins
transcription
peroxisomes are organelles found in most – cells
eukaryotic
peroxisome breaks down very long chain fatty acids through –
beta-oxidation
in animal cels, the peroxisome converts the very long fatty acids into medium chain fatty acids, which are subsequently shuttled to the – where they are eventually broken down via oxidation into CO2 and H2O
mitochondria
T/F: RNA can be found in nucleus, mitochondria, prokaryotic cells, and ribosomes
true
A vacuole is a membrane-bound organelle which is present in all – and – cells and some protist, animal, and bacterial cells
plant and fungal
vacuoles are enclosed compartments filled with water and contain inorganic and organic molecules (including enzymes in solution) and may contain – that have been engulfed
solids
the – and significance of vacuoles varies greatly according to the type of cell with greater prominence in plant cells
function
phosphotransferase is needed to form the mannose-6-phosphate tag that targets hydrolase enzymes to their lysosomal destination. Defective phosphotransferase causes I-cell disease. Which defective organelle gives rise to this condition?
Golgi
Golgi is part of the endomembrane system and serves as a cellular – center (packages, processes, modifies)
distribution
smooth ER is part of the endomembrane system an dis connected to the nuclear envelope and functions in several – processes
metabolic
smooth ER synthesizes
lipids, phospholipids, steroids
cells that secrete lipids, phospholipids, and steroids such as the testes, ovaries, and skin oil glands have an extensive –
smooth ER
smooth ER carries out metabolism of – and –
carbohydrates and steroids
smooth ER detoxifies –
drugs
smooth ER is responsible for the attachment of – on cell membrane proteins
receptors
mitochondria and chloroplasts are unusual organelles because they contain – encoded proteins
nuclear and organelle encoded proteins
the enzyme cytochrome c oxidase is a large – complex found in bacteria and mitochondrion of eukaryotes
transmembrane protein
– is the last enzymes in the electron transport chain of mitochondria (or bacteria) located in the mitochondrial (or bacterial) membrane
cytochrome c oxidase
cytochrome c oxidase receives an electron from each of four cytochrome c molecules and transfers the electrons to an O2 molecule, converting molecular oxygen to two molecules of –
H2O
cytoskeleton is integral in proper cell division because it forms the – and is responsible for separating sister chromatids during cell division
mitotic spindle
cytoskeleton is composed of – and –
microtubules and microfilaments
cytoskeleton gives the cell mechanical support, maintains its shape and functions in cell –
motility
mitochondria divide – to produce daughter mitochondria that incorporate some new nonradioactive and also inherit radioactive from the parent via semi conservation replication
autonomously
T/F: post-translational import of proteins involve the Golgi complex
true
width of animal cell
20 micrometers
ribosomes are composed of specific rRNA molecules and –
associated proteins
ribosomes are identified by the – coefficients (Svedberg units)
sedimentation
peroxisomes contain the enzyme – that decomposed H2O2 into H2O and O2
catalase
osmosis is a special type of diffusion involving water and is a form of – transport
passive
high solute and low solvent concentrations
hypertonic
low solute and high solvent concentrations
hypotonic
solvents always flow spontaneously from an area of –
high solvent to low solvent concentration
during osmosis, water flows rom a – to – environment
hypotonic to hypertonic
after chromosome disjunction, cyclin B is marked for destruction by the –
anaphase promoting complex
complex of Cdk and cyclin B is called a maturation or – promoting factor
mitosis
– is necessary for the progression of the cells into and out of M phase
cyclin B
mitochondria have their own DNA genetic material and – to manufacture their own RNAs and proteins
machinery
T/F: all organisms that reproduce sexually inherit mitochondrial organelle from their mother
true
mitochondrial genes cannot be – because all mitochondria are inherited from the mother
recessive
– is involved in the synthesis of phosphatidylcholine
smooth ER
examples of plastids
chloroplast and chromoplast
– are site of manufacturing and storage of important chemical compounds used by the cell and often contain pigments used in photosynthesis
plastids
plastids like prokaryotes contain a – double-stranded DNA molecule
circular
mitochondrial mutations are often limited to one – type
tissue
thyroid gland synthesizes – in response to high blood calcium levels
calcitonin
calcitonin acts to reduce blood calcium, opposing the effects of –
parathyroid hormone
calcitonin lowers blood Ca2+ by inhibiting the absorption of Ca2+ by –
intestines
calcitonin lowers blood Ca2+ by inhibition of – activity in bones
osteoclast
calcitonin lowers blood Ca2+ by inhibition of renal tubular reabsorption of Ca2+, allowing it to be –
excreted in urine
kidneys are essential in the urinary system and serve homeostatic functions such as the regulation of – , maintenance of pH balance, and regulation of blood pressure (via salt and water balance)
electrolyes
kidneys secrete – (involved in blood pressure regulation) that induces the release of aldosterone from the adrenal cortex
renin
secretion of renin – blood pressure via sodium reabsorption
increases
PTH – blood calcium
increase
high levels of Ca2+ in bone and kidney involves – receptor
PTH 1
high levels of Ca2+ in CNS, pancreas, testes, and placenta involves – receptor
PTH 2
largest organ
liver
T/F: liver function includes detoxification, protein synthesis, and production of biomolecules necessary for digestion
true
liver synthesizes – which emulsifies lilies in the small intestine
bile
rough ER is involved in the synthesis of – proteins
plasma membrane
active protein involves a – and uses energy to move a substance across a membrane agains (up) a concentration gradient
carrier protein
refers to how some ionic species can pass through the barrier while others cannot
Donnan equilibrium
the presence of a different charged substance that is unable to pass through a membrane creates an –; the electrical potential arising between the solution is the Donnan potential
uneven electrical charge
overexpression of cyclin D promotes an unschedules entry into –
S phase
synthesis of cyclin D is initiated during – and drives the G1/S phase transition
G phase
biochemical events lead to characteristic cell changes (morphology) and death which include – (irregular bulge in plasma membrane), cell shrinkage, chromatin condensation, nuclear fragmentation and chromosomal DNA fragmentation
blebbing
programmed cell death
apoptosis
traumatic cell death that results from acute cellular injury, whereas apoptosis conferees advantages during an organism’s life cycle
necrosis
unlike necrosis, apoptosis produces cell fragments called – that phagocytic cells are able to engulf and quickly remove before the contents of the cell can spill out onto surrounding cells and cause damage
apoptotic bodies
a failure in which stage of spermatogenesis produces nondisjunction that results in a male having a XXY?
anaphase I
During meiosis anaphaseI, – separate
homologous chromosomes
During meiosis anaphase II, – separate
sister chromatids (identical copies, except for recombination)
In sperm, X and Y would be “homologous chromosomes” and would normally separate during meiosis I; failure to do so would create a sperm containing both X and Y which causes –
Klinefelter syndrome
Anaphase is when the – splits and the homologous chromosomes/sister chromatids are drawn away (via spindle fibers) from each other toward opposite sides
centromere
– is observed in females due to a single X karyotype (single X chromosome and lacking a Y)
Turner’s syndrome
protein targeting occurs during the synthesis of which type of proteins?
secreting proteins
most proteins that are secretory, membrane-bound, or targeted to an organelle use the – sequence of the protein to target the protein
N-terminal signal sequence (5-30 amino acids)
the signal sequence of the polypeptide is recognized by a – while the protein is still being synthesized on the ribosome
signal recognition particle (SRP)
protein synthesis pauses while the – is transferred to an SRP receptor on the ER (in eukaryotes) or to the plasma membrane (in prokaryotes) before translation of the polypeptide resumes
ribosome-protein complex
free ribosomes produce proteins in the –
cytosol
attached ribosomes produce proteins that are inserted into the –
ER lumen
the concentration of growth hormone receptors will significantly reduce after selective destruction of –
plasma membrane
all anterior pituitary hormones including GH are – hormones
peptide hormones
peptide hormones are hydrophilic and cannot pass across the hydrophobic phospholipid bilayer, and therefore peptide hormones bind to receptors on the –
plasma membrane
urea, a byproduct of amino acid metabolism, is a small uncharged molecule and therefore crosses the cell membrane by –
simple diffusion
export of Na+ from a neuron is coupled with the import of –
K+
the sodium-potassium-ATPase pump (ATP dependent process) is necessary for the maintenance of a – across the neuron membrane
voltage potential
movement of Ca2+ into a muscle cell occurs against the concentration gradient and Ca2+ enters by – which requires ATP
active transport
synaptic vesicles contain – and their exocytosis at a nerve terminus is an ATP-dependent process that is triggered by an action potential propagating along the neuron
neurotransmitters
p53 is a tumor suppressor protein that regulates the cell cycle and prevents –
cancer
– is 1/2 the mass of carbon and is a unit of convention for expressing the molecular mass of proteins
Dalton
newly synthesized secretory protein: …. –> exterior of cell via exocytosis
rough ER, Golgi, secretory vesicles
cholesterol is normally found dispersed in varying amounts throughout animal cell membranes in the irregular spaces between the – of the membrane
hydrophobic tails
cholesterol – fluidity of the membrane because it confers stiffening and strengthening effects on the membrane
decreases
proteins targeted to the Golgi from the rough ER have three destinations: –, transported into organelles or targeted to the plasma membrane as a receptor, channel or pore
secreted out of the cell
the presence of – differentiates a protein from a carbohydrate molecule
nitrogen
most abundant plasma protein
albumin
because albumin is too large to pass from the circulatory system into the interstitial space, it is primarily responsible for the – of the circulatory system
osmotic pressure
osmotic pressure is the force of H2O to flow from an area of – solute to – solute concentration
lower solute to higher solute concentration
capillaries are – to albumin
impermeable
increasing albumin solute concentration in the arteries/capillaries increases the movement of H2O from the interstitial fluid to – the osmotic pressure in the arteries/capillaries
reduce
retinoblastoma protein (pRb or RB1) is a – that is dysfunctional in several major cancers
tumor suppressor protein
one function of RB1 is to prevent – by inhibiting cell cycle progression until a cell is ready to divid
excessive cell growth
RB1 also recruits several – such as methylases and acetylases
chromatin remodeling enzymes
– prevents cells from replicating damaged DNA by preventing its progression along the cell cycle through G1 into S phase
RB1
glycolysis occurs in the –
cytoplasm
oxidation of pyruvate into acetyl-CoA and the Krebs (TCA) cycle occur in the –
mitochondrial matrix
ETC (cytochrome) occurs in the –
inner membrane of the mitochondria
ETC (H+ proton gradient) occurs in the –
inter membrane space of the mitochondria
pyruvate is oxidized to acetyl-CoA as a preliminary step before joining – in the Krebs cycle, which occurs in the mitochondrion
oxaloacetate
most abundant lipid in the body
triglycerides
minerals (potassium, sodium, calcium, magnesium) are essential nutrients because they must be consumed in the diet and act as – (nonorganic components) for enzymes
cofactors
T/F: minerals are digested by lysosomes
false
recycling of organelles within the cell is accomplished through – by the lysosomes
autophagy
albumins are – proteins
globular
T/F: carotenoids and lecithin are lipid derivatives
true
defective attachment of a chromosome to the spindle blocks the activation of the – complex
anaphase promoting
in meiosis II, human cells have a single – copy of the genome
unreplicated
centrioles are cylindrical structures composed mainly of –found in most eukaryotic cells (except flowering plants and fungi)
tubulin
centrioles are involved int eh organization of the mitotic spindle and in the completion of –
cytokinesis
centrioles contribute to the structure of the – and are involved in organizing microtubules in cytoplasm
centrosomes
position of the centriole determines the position of the – and plays a crucial role in the spatial arrangement of the cell
nucleus
– are the organizational sites for microtubules (i.e. spindle fibers) that assemble during cell division
centriole
cAMP is a – triggered when a ligand (peptide hormone or neurotransmitter) binds to a membrane-bound receptor
second messenger
through a G-protein intermediate, the – is activated and converts ATP into cAMP
adenylate cyclase
adenylate cyclase is attached to the inner layer of the –
phospholipid bilayer
placed in a hypertonic solution, erythrocytes will undergo – as osmotic pressure draws water out of the cell and the cell shrivels
crenation
peroxisomes are abundant in the –
liver
– are hollow proteins composed of tubulin monomers
microtubules
microtubules are necessary for the formation of the – that separates chromosomes
spindle
T/F: microtubules are necessary for the synthesis of cilia and flagella
true
T/F: microtubules are necessary for the formation of the cell cytoskeleton within the cytoplasm
true
actin and myosin are – fibers in muscle cells
contractile
actin and myosin are composed of –
microfilaments
a cell division where each of the two daughter cells receives a chromosome complement identical to that of the parent is –
mitosis
– interfere with microtubule formation
colchicine
amoeboid moves using pseudopodia which are bulges of cytoplasm powered but eh elongation of flexible – not microtubules
microfilaments
microtubules are long, hollow cylinders made up of polymerized alpha and beta –
dimers
T/F: apoptosis occurs both in fetal development and during ageing
true
high level of DNA synthesis occur in cells such as – cells that use mitosis for rapid reproduction
skin cells
coat-proteins like – are used to build small vesicles to safely transport molecules within and between cells
clathrin
clathrin is a protein that is collected on the – side of the cell membrane and functions in the coordinated pinching off of membrane into receptor-mediated endocytosis
cytoplasmic
a lipid-soluble toxin that inactivates clathrin results in – delivery of polypeptide hormones to endosomes
reduced
in osmosis, H2O always flows from a region of – osmotic pressure to a region of – osmotic pressure
lower to higher
