CELL BIOCHEMISTRY Flashcards
smallest unit that is capable of performing life functions
cell
cell theory states that:
All living things are made up of cells.
- All cells come from pre-existing cells through
cell division
basic types of cells (2)
prokaryotes
eukaryotes
cells without a nucleus or membranebound organelles.
- Includes bacteria and archaebacteria
prokaryotes
cells with nucleus and membrane-bound
organelles.
- Includes cells from plants, animals, fungi, and
protists
eukaryotes
common cellular structures of prokaryotes
plasma membrane
cytoplasm
ribosomes
nucleoid
The genetic material in bacteria
nucleoid
genophore
bacterial DNA
irregular aggregate of genophore or
bacterial DNA and nucleoid-associated proteins
nucleoid
___ is made-up of circular, doublestranded piece of DNA.
bacterial DNA
small circular,
double-stranded DNA that is physically separate from
the nucleoid
plasmids
replicated independently of
the genophore and may contain genes that enhance the survival of bacteria such as antibiotic resistance genes
plasmids
bacterial cell wall is made up of
peptidoglycan
these are polysaccharides and protein aggregates
peptidoglycan
made-up of phospholipid
bilayer with embedded proteins which delineates and protects the cell as well as regulating the passage of materials into and out of the cell
plasma membrane
large polysaccharide structure that forms the outermost envelope and contains water which prevents the bacteria from drying out. It may also serve as protection from phagocytosis or being eaten by immune cell
thereby increasing the virulence or disease-causing ability of such bacteria
capsule
Many bacteria have _____ which helps in environmental interaction such as pili, fimbriae,
and flagellum
proteinaceous appendages
hair-like in appearance and utilized for surface
attachment or DNA exchange of DNA with another bacterium
pili
also hair-like but are
shorter and more numerous
fimbriae
whip-like structure
that can propel a bacterium for movement.
flagellum
chromosomes in prokaryotes are usually ___ rather than linear
circular
bacteria reproduce through ___
binary fission
larger cells five times the size of a prokaryotic cell with an average size of about 50
micrometers
eukaryotic cells
have membrane-bound nucleus and other
membrane-bound organelles unlike prokaryotic cells
eukaryotes
Plant cells are unique from animal cells due to the presence of ____ and __ cell wall.
chloroplast
cellulosic
Fungi cells also have cell walls but are made up of ___
chitin
N-acetylated form of cellulose
chitin
made up of cellulose, a
homopolysaccharide of the simple sugar glucose
cell wall
plant’s cell wall which is made up of ____ that are
cross-linked with ___
cellulose microfibrils
pectin
pectin is a heteropolysaccharide of the sugars ____ and ____
galactose
galacturonic acid
has gel-like characteristics which binds the cellulose microfibrils together.
pectin
During ___, the cell membrane loses water and
its contents shrink up into a ball, while the outer cell
wall remains intact
plasmolysis
Shrubs and trees have a thickened secondary cell wall
which contains ___
lignin
a brown phenolic polymer that
imparts great strength and hardness to wood
lignin
provides structural support to plant cells and prevents the plant cells from bursting under high
turgor pressure
cell wall
who cretted the fluid mosaic model
singer
nicolson
describes the structure of the
plasma membrane as composed of a phospholipid bilayer with embedded proteins
fluid mosaic model
are complex of polar phosphate head and non-polar hydrocarbon (lipid) tails which is amphipathic in nature
phospholipids
has dual polarity
amphiphatic
proteins that are embedded in the phospholipid layer can be
integral membrane protein
peripheral membrane protein
proteins that are embedded through the bilayer
IMP
proteins that are embedded only at one side of the bilayer
PMP
___ are IMP with associated sugar moieties or chain that serve as cell surface receptors for cell
recognition, membrane transport, or cell communication
glycoproteins
___ are lipid with sugar moieties that function more for cell recognition
glycolipids
organelles with phospholipid bilayer (some)
vacuoles
nucelus
mitochondria
chloroplasts
delineates the cell from its
environment, protects the cell, and regulates the passage of materials into and out of the cell.
plasma membrane
Ions pass through the plasma membrane via ____ by ___ and ____
which requires ___
carrier molecules
active transport
facilitated diffusion
ATP
made up of various protein
scaffolds inside the cytoplasm which provides structural
support to the cell and aid in cellular movement
cytoskeleton
(3) classifications of cytoskeleton
microtubules
intermediate filaments
microfilaments
thickest of the cytoskeleton
structures with an average diameter of 25 nanometer
microtubules
are rigid hollow cylinders which are polymers of ___ and ____
alpha
beta tubulin protein
The two forms of tubulin form ___ or ___ which come together to form the hollow cylinders which is the characteristic form of the microtubules
pairs
dimers
They maintain cell shape and hold organelles in place and allow them to move around inside the cell. They
prominently form the ____ during cell division
which moves the chromosomes
microtubules
mitotic spindle
microtubules are also the protein component of the cell appendages such as
cilia
flagella
numerous hair-like cell surface projections
cilia
longer whip-like structure for locomotion
flagella
have an average diameter of 10
nanometer and have different composition depending
on the cell type
intermediate filament
example of intermediate filaments
keratin
vimentin
desmin
neurofilment
lamin
provide support and
mechanical strength to the associated cellular parts and
components
intermediate filament
are the thinnest of the cytoskeleton
with an average diameter of 7 nanometer
microfilaments
microfilament is made of
two thin actin chains that are twisted around one
another to form a ___
helical configuration
___ and __ are responsible for muscular contraction
actin
myosin
Microfilaments also form ____
cytoplasmic extension
cytoplasmic extension;
numerous microscopic fingerlike projections of the small intestine which increases its
surface area for nutrient absorption
microvilli
cytoplasmic extensions
temporary arm-like extension of the plasma membrane
for movement of certain cells or organisms
pseudopods
(2) cytoplasmic extension
microvilli
pseudopods
gel-like aqueous region
between the cell membrane and nuclear membrane
cytoplasm
polar solutes that are dissolvved in the cytoplasm
sugars
amino acids
peptides
ions
insoluble cellular inclusions
responsible for production of
adenosine triphosphate (ATP), the energy currency of
the cell
mitochondria
shape of mitochondria
ovoid
elongated
The ___ of mitochondria is convoluted to increase its
surface area for ATP production by electron transport chain and oxidative phosphorylation (ETC-OP).
inner membrane
mitochondria have their own small genome which is ___ inherited
maternally
organelle that consists of an interconnected network of flattened
membranous sacs, called ____
endoplasmic reticulum
cisternae
made up of tubular sacs without studded ribosomes
sER
ER that is involved in lipid and carbohydrate biosynthesis
sER
also involved in the storage and release of calcium ions in cells and in the detoxification of drugs
and toxicants such as in the liver cells (hepatocytes)
sER
is studded with ribosomes and have a flattened appearance
rER
involved in the manufacture of various proteins in the cell on the ribosomes that studs its
surface. (ER)
rER
rER also modifies proteins by ____ or attachment of sugar moieties and in the ____ of proteins into its proper shape or conformation
glycosylation
proper folding
are ribonucleoproteins (RNA +
protein) particles that serve as the site for protein synthesis in the cell in the process called ____
ribosomes
translation
ribosomes may appear in clusters called ____
polyribosomes
Ribosomes may appear in clusters, or as single free-floating miniscule body in the cytoplasm or attached at the cytoplasmic side of
the plasma membrane, rER, or the nucleus. (t/f)
true
ribosomes are made up of ___
two subunits
ribosomal large subunit
60S eukaryotes
50S prokaryotes
ribosomal small subunit
40S eukaryotes
30S prokaryotes
modifies, packages, and “tags” proteinsthat were received from the rER for transportation to
their destined location in the cells.
golgi apparatus
GA is made up of highly-folded flattened sacs called
cisternae
Present mostly in animal cells and largely absent in plant cells and acts as the cell’s “garbage
disposal organelle.”
lysosomes
lysosomes contain various ____ that break proteins, polysaccharides, lipids, nucleic acids, and even
worn-out cellular organelles
acidic hydrolytic enzymes
These enzymes are active at ___ the cytoplasm (lysosomes)
pH below
enzymes in the lysosomes are are ____ in the lysosomes to protect the other cell parts from degradation by these digesting enzymes
compartmentalized
are small, spherical organelles
enclosed by single membrane layer instead of a double layer for most organelles.
peroxisomes
peroxisomes carry out ___ reactions
redox
redox reactions in peroxisomes
oxidative breakdown of fatty acids and amino acids
are also crucial in degrading toxic substances inside the cell such as hydrogen peroxide, H2O2, which
would be damaging to cells as it triggers free radical
damage
peroxisomes
Hydrogen peroxide is broken down by the enzyme called ___ which facilitates its conversion to oxygen
gas and water.
catalase
specialized peroxisomes in plants which converts stored
fatty acids into sugars particularly in germinating seeds
glyoxysomes
membrane-bound
sacs for storage and transport of materials within the
cell. (2)
vacuoles
vesicles
larger than vesicles and they do
not fuse with the membranes of other cell organelles
vacuoles
Plants cells typically have ___ that can occupy as much as 80% of the cell’s volume. They serve to maintain water balance in plants and also for the storage and degradation of polar waste products.
large central vacuole
are smaller in size and can fuse with other vesicles or cell organelles. They can store materials inside or transport them outside the cell
vesicles
pair of cylindrical
proteinaceous organelles just outside the nucleus of
animal cells
centrioles
Each centriole is made up of ___ of microtubules that are arranged in a ___ around a central hollow region (___)
nine triplets
cartwheen fashion
9+0 pattern
The centrioles form the ___ during cell division that move the chromosome across the cell.
spindle fibers
unique plant cell
organelles that carry out photosynthesis through the
green pigments that it contains, the ____
chloroplasts
chlorophhyll
chloroplasts also has its own
DNA and ribosomes and can therefore independently
carry out the replication and expression of its genetic
materials (t/f)
chloroplasts
houses the DNA that directs the synthesis of ribosomes and proteins in the cell
nucleus
is a membranebound distinct organelle which is darkly stained for
microscopic visualization
nucleus
__ is the DNA of the nucleus that is associated with nuclear proteins called ___
chromatin
histones
the ___ has condensed chromatin
and serves as the site for ribosome synthesis in the process called ____
nucleolus
transcription
the boundary of the nucleus which has a similar stucture to the plasma membrane except for the presence of the ___
nuclear envelope
nuclear pore complex
the nuclear pore complex (NPC) which allows the passage of relatively large molecules such as
__ and __ across the membrane
RNA
proteins
The ___ is continuous with the endoplasmic reticulum where proteins are packaged
and transported.
nuclear membrane
how can you best describe cytoplasm
It is polar, viscous environment
It is delineated by the phospholipid
bilayer of the nucleus and the cell
membrane.
characteristics of the
bacterial appendages
✓ They aid in locomotion, conjugation,
and cell surface attachment
✓ They are made up of amino acids
How does the fluid mosaic model represents the
structure of the plasma membrane?
✓ The primary component is the
phospholipid bilayer with the
hydrophobic hydrocarbon tail at the
core.
✓ The proteins are embedded which can be located at one side of the lipid bilayer or passing through it.
Insulin is a protein produced by the pancreas and released into the bloodstream for lowering
blood glucose level. Which organelles are directly involved in the synthesis and eventual
release of insulin?
✓ Golgi apparatus and vesicles
✓ Ribosomes and rER
What are Gram-positive bacteria?
✓ They retain crystal violet dye and thus are stained purple.
✓ They have a cell wall made-up of a thick layer of peptidoglycan.
If asked about the mitochondria, how will you best describe such organelles?
✓ They metabolize sugars, amino acids, and fatty acids through a series of reactions that yield energy in the form of ATP.
✓ They have two membranes and the inner membrane has distinct infoldings
organelles (2) unique in animal cells
lysosomes
centrioles
cell parts/organelles (2) present in both prokaryotic and eukaryotic cells
ribosomes
plasma membrane
Which organelles are involved in protein synthesis, modification, and/or transport?
✓ Ribosomes and rER
✓ Golgi apparatus and vesicles
Among the given organelles, which ones are present or prominent in plant cells but not in
animal cells?
✓ Vacuoles (central)
✓ Chloroplasts
Among the given statements, which ones do not describe the centrioles?
✓ They are active at all times in the cell
✓ They are prominent in all eukaryotic cells
Which of the following are true for
cytoskeleton?
✓ They are filamentous in shape and function for support and movement
✓ They are made-up of amino acids
polymers
cell organelles (2) that are not enclosed by a phospholipid bilayer
ribosomes
peroxisomes
What distinguishes prokaryotes from eukaryotes?
✓ The absence of membrane-bound organelles
✓ The absence of membrane-bound nucleus
Which cell organelles have “house cleaning” functions in the cell?
✓ Vacuoles and peroxisomes
✓ Lysosomes and sER
Which of the following are not features of the nucleus?
✓ Its nuclear envelope is fundamentally different from the plasma membrane.
✓ It is directly involved in protein
synthesis
Which of the following is wrong about the chloroplasts?
✓ It can release energy in the form of ATP just like mitochondria
✓ The stroma contains the green
photosynthetic pigments
Which of the following are descriptive of the bacterial DNA?
✓ It is made up of circular doublestranded DNA
✓ There is an extrachromosomal DNA in bacteria which replicates independently
Among the given statements, which are characteristics of cell wall?
✓ The plant cell wall is made up of glucose polymers that are cemented by pectin or lignified.
✓ Cell wall is present in bacteria, plants, and fungi
Which of the following are true for bacterial capsules?
✓ They are made up of hydrated
carbohydrate complex
✓ They help the bacteria in evading our immune system
