Cell Structure Flashcards
cluster of atoms held together by chemical bonds
molecule
structure within a cell that performs a specific function
organelle
simplest entity that has all the properties of life; a membrane-bounded unit containing DNA and cytoplasm
cell
a group of similar cells that carry out a particular function
tissue
structures composed of more than one type of tissue
organ
related organs performing a common function
organ system
an individual, independent, living entity
organism
Cells are small to maintain a large – ratio in order to function
surface area to volume
all prokaryotic cells have a plasma membrane, nucleoid, and cytoplasm containing –
ribosomes
outside prokaryotic cells may be a –
cell wall
bacteria’s cell wall contain –
peptidoglycan
prokaryote that photosynthesizes?
cyanobacteria
some prokaryotes swim using
flagella
what is projected from the surface of prokaryotic cells that is involved in mating
pili
eukaryotic cells contain an internal cytoskeleton that maintains – and moves materials
cell shape
plant cell wall is mainly composed of
cellulose
largest organelle; contains most of the cell’s DNA
nucleus
nuclear envelope is made up of two membranes perforated by –
nuclear pores
DNA is combined with protein to form –
chromatin
when the nucleus is about to divided chromatin condenses and coils tightly forming –
chromosomes
each chromosome (“colored body”) contains – which is comprised of many genes
one long molecule of DNA
T or F: the nucleus may contain more than one nucleolus
True
site of ribosome assembly
nucleolus
fluid material within the nuclear envelope
nucleoplasm
a network of proteins which maintains shape of nucleus
nuclear lamina
all cells synthesize proteins on
ribosomes
3 locations of ribosomes in eukaryotes
- free in cytoplasm
- attached to ER
- in energy-producing organelles (mitochondrial matrix, chloroplast stroma)
cells which synthesize proteins for export contain large amounts of –
ER
site for hydrolysis of glycogen
smooth ER
synthesis of steroids
smooth ER
makes proteins
rough ER
site for addition of short sugar chains to proteins (glycoproteins)
rough ER
cis Golgi apparatus lies closer to –
nucleus
trans Golgi apparatus lies closer to –
cell surface
modifies, packages, and sorts proteins
Golgi apparatus
synthesizes some polysaccharides for the cell wall
Golgi apparatus
vesicles from the rough ER fuse with the – region of the Golgi apparatus and secretory vesicles are pinched off the the – region
cis, trans
specific hydrophobic sequence of about 25 amino acids at the beginning of a polypeptide chains directs it into the ER
signal sequence
signal sequence is removed by –
an enzyme
converts energy from food in to ATP
mitochondria
the size of mitochondria is similar to
bacteria
the inner membrane of the mitochondria is highly folded forming –
cristae
part of the mitochondria that contains ribosomes and DNA
matrix
almost all eukaryotes contain mitochondria except those –
living in environments without oxygen
more mitochondria are present if cells are –
very active
plastids are present in –
plants and some proteins
serves for food manufacture or storage
plastids (e.g. chloroplasts carry out photosynthesis)
plastids are surrounded by – membranes
2 unfolded
inner membrane of plastids form a stack of flattened disk-like sacs called
thylakoids
stacks of thylakoids are called
grana
chlorophyll is contained in the
thylakoid membrane
fluid within inner membrane of chloroplast
stroma
contain hydrolytic digestive enzymes
lysosomes
participate in phagocytosis
lysosomes
organelle that break downs and stores in plants and animals
peroxisomes
organelle that break downs and stores in plants only
glyoxysomes
vacuoles are present in plant cells and store – and provide –
waste, turgor
maintains cell shape, facilitates cell movement and certain fibers act as tracks for “motor proteins”
cytoskeleton
organelle involved in support present in plants, fungi, bacteria, and some protists
cell wall
surround animal cells and is composed of protein (collagen, glycoproteins, and proteoglycan)
extracellular matrix
components of cytoskeleton
microfilaments, intermediate filaments, and microtubules
strands of actin
microfilaments
involved in movement during animal division
microfilaments
muscle contraction
microfilaments
tough, fibrous protein molecules twisted into rope-like structures, which stabilize cell structure
intermediate filaments
hollow cylinders made of tubulin
microtubules
involved in structure and function of cilia and flagella, centrioles and movement of cellular organelles
microtubules
motor proteins like – and – use energy from ATP to change their shape and move things
dynein and kinesin
All cells are bounded by a
plasma membrane
A plasma membrane provides a – which has the ability to transport certain molecules
permeability barrier
The plasma membrane plays a key role in the –
response of cells to external stimuli
Plasma membranes are also involved in energy –
transduction
Membranes of composed of —
lipids, proteins, and carbohydrates
– provide physical integrity to membranes
lipids
– perform specific functions for the membranes such as transport
proteins
– serve as recognition sites on the cell surface
carbohydrates
phospholipids spontaneously form bilayer sheets in which the – point inward
hydrophobic tails
as temperatures falls, lipid bilayer changes from a – state to a – state
fluid, rigid (gel)
if the hydrocarbon chains of a bilayer sheet are short or have double bonds then the temperature of the phase transition is –
lower
important component of plasma membrane of animal cells orients in bilayer with polar head group close to polar head group of phospholipid
cholesterol
the nonpolar interior of the lipid bilayer prevents passage of any – molecules through the bilayer
water-soluble
permeability of water-soluble molecules occur because of –
specific protein molecules
explains how proteins are incorporated into the lipid bilayer
fluid mosaic model
on the outer surface of the plasma membrane carbohydrates are attached to –
proteins or phospholipids
– proteins penetrate into the lipid bilayer
integral
most integral proteins are – proteins that penetrate all the way through the bilayer
transmembrane
transmembrane proteins contain an alpha-helix of — extending across the hydrophobic interior of the membrane
nonpolar amino acids
located outside the lipid bilayer on the cytoplasmic surface attached by non covalent bonds to the polar head groups of the lipid bilayer or to integral membrane proteins
peripheral proteins
covalently attached to a phospholipid or fatty acid embedded in the bilayer
lipid-anchored proteins
beneath the cytoplasmic surface of the red blood cell – forms a mesh
spectrin
3 main roles of membrane proteins
- transport proteins
- receptors for molecular messengers from other cells
- form junctions between cells
most carbohydrates in membranes are bound to proteins forming –
glycoproteins
– form cell identity markers
glycolipids
cells recognize and bind to each other via –
surface membrane proteins
3 types of cell adhesion
tight junctions, desmosomes, and gap junctions
within cells, solutes distribute rapidly by – due to the short distances involved
diffusion
movement is down the concentration gradient
diffusion
movement is against the concentration gradient
active transport
– can diffuse across the lipid bilayer
small nonpolar molecules like oxygen and carbon dioxide
molecules with – diffuse more rapidly
higher lipid solubility
diffusion of water molecules across a selectively permeable membrane
osmosis
water diffuse out of a cell
hypertonic
water diffuse into a cell
hypotonic
T or F: ions (Na+) being charged can readily cross membranes
false
ions pass through – to cross membranes
aqueous channels created by intrinsic membrane proteins
certain molecules (glucose) bind to – in the membrane and are transported across
carrier proteins
facilitated diffusion is – and may become – if all the protein carriers are in use
specific, saturated
– active transport requires the direct participation of ATP
primary
– active transport utilizes the energy in an ion gradient established by primary active transport
secondary
the sodium-potassium pump is an example of – active transport
primary
transports macromolecules, large particles, and small cells into eukaryotic cells
endocytosis
in endocytosis, the – envelops materials and forms a vesicle inside the cell
plasma membrane
large particles are engulfed
phagocytosis
small dissolved solutes or fluids enter a cell
pinocytosis
a specific membrane receptor binds to a particular macromolecule at sites called coated pits
receptor-mediated endocytosis
uptake of cholesterol in association with LDL is an example of – endocytosis
receptor-mediated
materials in vesicles are secreted from the cell when vesicles fuse with the plasma membrane
exocytosis
first law of thermodynamics
energy cannot be created or destroyed
second law of thermodynamics
during any energy interconversion, some energy is released as heat which adds to the entry of the system
the sum of all chemical processes occurring within a cell or organism
metabolism
chemical reactions establish –
equilibrium
the – is the ration of the concentration of products and reactants at equilibrium
equilibrium constant
a – indicates that the reaction goes far towards completion
high equilibrium constant
the breaking of chemical bonds in the course of chemical reactions produces changes in –
Gibbs free energy
