cellular Flashcards
the cell can divided into how many parts and what are they called
3 parts
plasma (Cell) membrane, or plasmalemma
cytoplasm - cytosol and organelles
nucleus - chromosomes and genes
what is the plasma membrane
The plasma membrane (plasmalemma) is a flexible yet sturdy
barrier that surrounds and contains the cytoplasm of the cell
what are the 2 types of membrane proteins
Integral (also called transmembrane) proteins
2. Peripheral proteins
list the membrane proteins and their type
ion channel - integral
carrier - integral
receptor - integral
enzyme - integral and peripheral
linker - integral and peripheral
cell identity marker - glycoprotein
are membranes fluid structures and why
yes because most of the lipids and the proteins move easily in the bilayer
Membrane lipids and proteins are mobile in their own
half of the bilayer
what does cholesterol do in the membrane
Cholesterol serves to stabilize the membrane and
reduce membrane fluidity
what is permeability of the membrane
selective
what is the plasma membrane permeable to
The lipid bilayer is always permeable to small,
nonpolar, uncharged molecules
what increases the permeability of the membrane
Transmembrane proteins that act as channels or
transporters
how can macromolecules pass through the plasma membrane
vesicular transport
what is a concentration gradient
the difference in the
concentration of a chemical between one side of the
plasma membrane and the other
what kind of gradient is the difference in concentration of
ions between one side of the plasma membrane and the
other
electrical gradient
what are the 2 gradients make up
electrochemical gradient
what are the transport processes that move substances across the cell membrane
Passive processes
o Simple diffusion
o Facilitated diffusion
o Osmosis
Active processes
o Primary and secondary transport
o Vesicular transport
passive transport processes always move chemicals where
down their concentration gradient
active transport uses what and moves chemicals where
energy in ATP molecules to move chemicals up their concentration gradients
what can diffuse through the phospholipid bilayer and why
gases and some molecules can diffuse because they are small or non-polar (eg. O2 CO2 H2O)
how can ions diffuse through
they go through membrane pores or gated channels via membrane proteins
are pores always open?
yes
what determines more ions to diffuse
more pores allow more ions
are gated channels always open?
no
how is glucose diffused and what type of diffusion
faciliatated diffusion and diffuses with a transporter protein
what increases glucose diffusion
insulin because it increases transporters which means more glucose to pass through
how does water pass through membrane and which way does it go in terms of concentration
osmosis and it moves down its concentration gradient from a high concentration to a low concentration
more ions results in what water concentration in a solution
lower water concentration
less ions results in what water concentration in a solution
higher water concentration
what happens to water osmosis when there is an isotonic solution which is an equal amount of ions in both solutions
water moves in equal amounts in both directions
hypertonic is what and where will water go
has a lower concentration of water so water will from outside to inside
hypotonic is what and where will water go
has a high concentration of water so water will from inside to outside
in a hypotonic solution, where is the solute concentration higher?
where is the water concentration higher?
so what would happen to the cell
inside the cell
outside the cell
it may burst cause of water going in
in a hypertonic solution, where is the solute concentration higher?
where is the water concentration higher?
so what would happen to the cell
outside the cell
inside the cell
shrink
which way do molecules go with primary active transport and how
molecules move against their concentration gradient via pumps energized by the hydrolysis of ATP
how does the cell maintain water balance
actively transporting ions
how does secondary active transport work
uses gradients of sodium or hydrogen ions to move other ions
how does low calcium concentration maintain itself in the cytosol
by secondary active transport, which uses antiporters to move calcium out of a cell while sodium flows in
what is an example of secondary active transport involving digestive tract
absorption of nutrients from digestive tract with symporters into intestinal cells (like amino acids and glucose)
what is a vesicular transport that helps with large particles and how does it work
endocytosis uses energy from ATP and helps large particles or macromolecules to enter a cell
a small, round sac called
vesicle formed from the existing membrane and surrounds the particles to be transported
what are the types of endocytosis
phagocytosis, pinocytosis, and receptor-mediated endocytosis, transcytosis
what is phagocytosis
vital defense system to fight and protect from disease to the body
bacteria bind to a receptor so the membrane and cytosol extend to form a pseudopod and it turns to a vesicle called a phagosome
phagosome will fuse with a lysosome and the enzymes will digest the bacteria
if some material isnt digested then it is dumped back into extracellular fluid
what is pinocytosis
process which the cell drinks a tiny droplet of extracellular fluid including its solutes
plasma membrane folds inward to form the vesicle and flows into the cytosol and again fuse with lysosomes for the solutes to be digested
what is receptor-mediated
imports needed materials like certain hormones, antibodies, vitamins and low density lipoproteins into a cell
materials attach to clathrin proteins located on a clathrin coated pit which form a vesicle. The vesicle recycles the clathrin proteins. The uncoated vesicle fuses with an endosome and the receptors are sorted. The vesicle brings the receptors back to the membrane. While the vesicle is transported to a late endosome which binds to a lysosome for digestion of substances
what is transcytosis
carrier vesicles cross the cell and releases into the extracellular fluid on the other side of the cell
what is exocytosis and what kind of transport
vesicular transport, moves large volumes of fluid or chemicals out of the cell
also secretion of neurotransmitters, hormones, and digestive enzymes
the cytoplasm has how many components
- Cytosol - also known as the intracellular fluid portion of
the cytoplasm - Organelles - the specialized structures that have
specific shapes and perform specific functions
cytoplasm
Cellular contents between plasma
membrane and nucleus—cytosol and
organelles.
Site of all intracellular activities
except those occurring in the
nucleus
cytosol
Composed of water, solutes, suspended
particles, lipid droplets, and glycogen
granules.
Fluid in which many of cell’s
metabolic reactions occur.
Cytoskeleton
The cytoskeleton is a network in the
cytoplasm composed of three protein
filaments: microfilaments, intermediate
filaments, and microtubules.
The cytoskeleton maintains shape
and general organization of cellular
contents; responsible for cell
movements.
organelles
Specialized structures with characteristic
shapes.
Each organelle has specific
functions.
centrosome
Pair of centrioles plus pericentriolar
matrix. The pericentriolar matrix contains
tubulins, which are used for growth
of the mitotic spindle and
microtubule formation.
cilia and flagella
Motile cell surface projections that
contain 20 microtubules and a basal
body.
Cilia: move fluids over cell’s surface;
flagella: move entire cell
ribosome
Composed of two subunits containing
ribosomal RNA and proteins; may be free
in cytosol or attached to rough ER.
Protein synthesis.
endoplasmic reticulum ER
Membranous network of
flattened sacs or tubules. Rough
ER is covered by ribosomes and is
attached to the nuclear envelope;
smooth ER lacks ribosomes.
Rough ER: synthesizes glycoproteins and
phospholipids that are transferred to
cellular organelles, inserted into plasma
membrane, or secreted during exocytosis;
smooth ER: synthesizes fatty acids and
steroids, inactivates or detoxifies drugs,
removes phosphate group from glucose-6-
phosphate, and stores and releases calcium
ions in muscle cells
golgi complex
Consists of 3–20 flattened
membranous sacs called saccules;
structurally and functionally
divided into entry (cis) face,
medial saccules, and exit (trans)
face.
Entry (cis) face accepts proteins from rough
ER; medial saccules form glycoproteins,
glycolipids, and lipoproteins; exit (trans)
face modifies molecules further, then sorts
and packages them for transport to their
destinations.
lysosome
Vesicle formed from Golgi
complex; contains digestive
enzymes.
Fuses with and digests contents of
endosomes, phagosomes, and vesicles
formed during bulk-phase endocytosis and
transports final products of digestion into
cytosol; digests worn-out organelles
(autophagy), entire cells (autolysis), and
extracellular materials
peroxisome
Vesicle containing oxidases
(oxidative enzymes) and catalase
(decomposes hydrogen peroxide);
new peroxisomes bud from
preexisting ones.
Oxidizes amino acids and fatty acids;
detoxifies harmful substances, such as
hydrogen peroxide and associated free
radicals.
Copyright
proteasome
Tiny barrel-shaped structure that
contains proteases (proteolytic
enzymes).
Degrades unneeded, damaged, or faulty
proteins by cutting them into small
peptides.
mitochondrion
Consists of an external and an
internal mitochondrial
membrane, mitochondrial cristae,
and mitochondrial matrix; new
mitochondria form from
preexisting ones.
Site of aerobic cellular respiration reactions
that produce most of a cell’s ATP. Plays an
important early role in apoptosis.
nucleus
Consists of a nuclear envelope
with pores, nucleoli, and
chromosomes, which exist as a
tangled mass of chromatin in
interphase cells.
Nuclear pores control the movement of
substances between the nucleus and
cytoplasm, nucleoli produce ribosomes,
and chromosomes consist of genes that
control cellular structure and direct cellular
functions.
what is autophagy
Digestion of worn-out organelles by lysosomal enzymes
* Organelle fuses with lysosome to make autophagosome
what is autolysis
Destruction of entire cell by lysosomal enzymes
what are the steps of protein synthesis
step 1: transcription
step 2: translation
transcription
Transcription occurs in the
nucleus and is the process by
which genetic information
encoded in DNA is copied onto a
strand of RNA to direct protein
synthesis
steps in transcription
Messenger RNA (mRNA) directs protein synthesis
2. Ribosomal RNA (rRNA) joins with ribosomal proteins to
make ribosomes
3. Transfer RNA (tRNA) binds to amino acid and holds it in
place during translation
translation
Translation occurs outside the nucleus and is the process of reading
the mRNA nucleotide sequence to determine the amino acid
sequence of the newly formed protein
DNA is found in
chromatin
the enyzme that bonds RNA nucleotides together
RNA polymerase
what is cell division
Cell division is a process by which cells reproduce themselves
what is in interphase
Period between cell divisions; chromosomes not visible under light
microscope.
what is mitosis and when does it occur
Mitosis results in the distribution of 2 sets of
chromosomes into 2 separate nuclei
Mitosis occurs when the nucleus of a cell divides
what are the steps of mitosis
prophase, metaphase, anaphase, telophase
what happens in prophase
During prophase chromatin condenses into chromosomes and
the nuclear membrane disappears and centrosomes move to
opposite poles
what happens in metaphase
During metaphase centromeres of chromosomes line up at the
metaphase plate
what happens in anaphase
During anaphase centromeres of chromosomes split and sister
chromatids move toward opposite poles of the cell
what happens in telophase
During telophase the mitotic spindle dissolves, chromosomes
regain their chromatin appearance, and a new nuclear
membrane forms
cytokinesis
During cytokinesis a cleavage furrow forms and eventually the
cytoplasm of the parent cell fully splits
G1 phase
Metabolically active cell duplicates most of its organelles and
cytosolic components; replication of chromosomes begins. (Cells
that remain in the G1 phase for a very long time, and possibly never
divide again, are said to be in the G0 phase.
S phase
Replication of DNA and centrosomes.
G2 phase
Cell growth, enzyme and protein synthesis continue; replication of
centrosomes complete.
mitotic phase
Parent cell produces identical cells with identical chromosomes;
chromosomes visible under light microscope
what are the destinies
Remain alive and functioning without dividing
2. Grow and divide
3. Die
mitosis vs meiosis
mitosis is somatic type
meiosis is gamete type
mitosis will make 2 cells and meiosis will make 4
the diploid will be identical to the chromosomes in the starting cell
the haploid represents half of the chromosomes in the starting cell
mitosis is 46 chromosomes or 2 sets of 23
meiosis only one set of 23
types of cell cancers
Types of Cancer
o Melanoma
o Sarcoma
o Osteogenic sarcoma
o Leukemia
o Lymphoma
* Growth and spread
o Angiogenesis
