gen bio 1 exam 2 Flashcards
what do hydrophilic heads on the phospholipid bilayer of the cell membrane allow
allows cells to be in contact with aqueous
solutions → Enables biological processes and biochemical reactions to occur
ribosome’s main function
protein synthesis
ribosome structure
dot-like, mRNA wedged between its 2 subunits
cell wall (prokaryotes)
composed of peptidoglycan, wraps around the cell membrane
- extra layer of protection, helps maintain
cell’s shape and prevents dehydration
capsule
outside of cell wall, composed of polysaccharides; enables cell to attach to surfaces
flagella
whiplike structure; used for locomotion
pili
tubelike structures outside the capsule; for exchanging genetic material during conjugation
fimbriae
thread like structures outside the capsule used to attach to a host cell or a surface
what is the purpose of bacterial conjugation via pili
to gain antibiotic resistance
what is the process of bacterial conjugation
- pilus of donor cell attaches to recipient cell
- F plasmid DNA material transfers
- donor regenerates its own plasmid
- both cells are F+
nucleus
houses the cell’s DNA and directs the synthesis of ribosomes and proteins
nuclear envelope
a barrier that separates the nucleus from the cytoplasm (inner and outer layers are composed of phospholipid bilayers)
function of nuclear envelope
Contains a variety of proteins that function in the organization of genetic material and the synthesis of proteins
nucleoplasm
semi-solid fluid inside the nucleus
nucleolus
darkly staining region within nucleus;
produces and assemble the cell’s ribosomes.
nuclear pore
holes on the nuclear envelope that allow for passage of materials in and out of nucleus
chromosomes
long DNA molecule comprising part or all of the genetic material of an organism; Has a 3d structure that is achieved by packaging proteins
chromatin
unwound versions of chromosomes
peroxisome
metabolizes waste (looks like circles)
vacuole
membrane-bound sacs that function in storage and transport
mitochondria
site of ATP production
lysosome
organelle that contains digestive enzymes; come from the Golgi apparatus
ER
interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids
rough ER
protein modification (e.g. folding and addition of modifications like phosphate group); has ribosomes on outer membrane
smooth ER
lipid and carbohydrate synthesis
lumen
hollow portion of the ER
Proteins that are synthesized in the rough ER are transported where
golgi apparatus
golgi apparatus
Sorts, tags, packages and distributes
proteins and lipids
golgi apparatus appearance
flattened membranous sacs
where are the cis and trans side of the golgi apparatus
Cis: side facing ER and nucleus
Trans: side facing plasma membrane
vesicle purpose
transport of materials to other parts of the cell or out of the cell
vesicle structure
structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer
* May contain proteins, lipids, ions and other organic
molecules
lysosome function
Break down excess or damaged cell parts
into their molecular subunits for reuse by
cell
* Destroy invading pathogens (e.g.) viruses
and bacteria.
* If cell is damaged beyond repair, lysosomes can help it to self-destruct (e.g programmed cell death, or apoptosis)
lysosome apperance
dark, almost spherical structures under the electron microscope
peroxisome function
Contains antioxidants to prevent oxidative
damage in cells
* Peroxisomes of animal cells contain catalase
catalase
an enzyme which converts hydrogen peroxide to water and oxygen
- antioxidant
mitochondria function
Functions in cellular respiration: process of generating ATP using the chemical energy in glucose and other nutrients
ATP
adenosine triphosphate; molecule that fuels many chemical reactions and biological processes
mitochondria structure
outer membrane, inner membrane, cristae (sacs), matrix (solution), ribosomes, DNA
what do plant cells have that animal cells dont
cell wall
chloroplasts
plasmodesmata
what do animal cells have that plant cells dont
lysosomes
centrosomes
tight junction
gap junctions
desmosomes
plant and animal cells have how many vacuoles
plant- 1; animal- multiple
vacuole purpose in plant cell
Vacuoles store water and help plant cells retain their shape and maintain ionic balance.
cell wall (plant cell)
rigid external layer of cellulose covering a plant cell
cell wall function
provides structural support, and gives shape to the cell; helps resist bursting when too much water comes into the cell
chloroplast
organelle found in plants and algae
where photosynthesis occurs
photosynthesis
series of chemical reactions that use carbon dioxide, water, and energy from light to generate glucose and oxygen
chlorophyll
green pigmented in chloroplast and captures the light energy that drives the chemical reactions of photosynthesis
centrosome
a substructure near the nucleus of a cell which functions in cell division; contains a pair of centrioles
centrioles
structures that lie perpendicular to each other from which the spindle fibers develop in cell division; has microtubules
cytoskeleton
network of protein fibers in the cytoplasm
cytoskeleton functions
maintain cell’s shape
* secure some organelles in specific positions
* allow cytoplasm and vesicles to move within the cell
* enable cells within multicellular organisms to move
types of cytoskeleton
- Microfilaments
- Intermediate filaments
- Microtubules
microfilaments
composed of two strands of actin filaments; thinnest; functions in movement of cytosol and vesicles, cell division, etc
intermediate filaments
composed of several strands of
fibrous proteins that are wound together; provides structural support (e.g. securing nucleus and other organelles in place)
Example: keratin
microtubules
small hollow tubes composed of α-tubulin
and β-tubulin; thickest of the three types of cytoskeleton
* helps cells resist compression; pulls replicated chromosomes to opposite ends of a dividing cell
extracellular matrix (ECM)
network consisting of extracellular macromolecules (e.g. proteins and carbohydrates) and minerals
extracellular matrix (ECM) purpose
provide structural support to the cells and neighboring cells
* Allows for communication with other cells e.g. collagen, glycoproteins, hydroxyapatite (bone)
animal cells communicate with neighboring cells via…
tight junctions, gap junctions, desmosomes
plant cells communicate with neighboring cells via…
plasmodesmata
tight junctions
watertight seal between two adjacent animal cells
desmosomes
adhesive intercellular junctions that allow two cells to be joined to each other (spot welds); allows tissues to experience stretching without tearing
gap junctions
channels between adjacent cells that allow for transporting ions, nutrients, and other substances that enable animal cells to communicate
plasmodesmata
channels between adjacent cells that allow for transporting ions, nutrients, and other substances that enable plant cells to communicate
organisms that are eukaryotes
plants, protists, fungi, animals
organisms that are prokaryotes
bacteria and archaea
3 ways materials transported across the cell membrane
- Passive transport
Subtypes: diffusion, osmosis, facilitated transport - Active transport
- Bulk transport
Subtypes: endocytosis, exocytosis
passive transport
Does not require energy to move substances across cell membranes
* Net movement of a material (solute) from an area of higher to lower concentration
diffusion
type of passive transport characterized by net movement of materials from an area of higher to lower concentration
- Usually involves unrestricted
movement of solute
by which process do lipids, gasses, and ethanol cross the cell membrane
diffusion
what molecules do not move through the cell membrane easily
large polar or highly charged molecules
how do large polar or highly charged molecules leave the cell membrane?
by facilitated transport
facilitated transport
movement material across the cell membrane with the help of protein channels or transporters;
facilitated transport
materials diffuse across the plasma membrane with the help of membrane proteins, still moving down the concentration gradient
transporters
proteins on the cell membrane that undergo a change in shape to allow a large material to pass through it
ion channels
proteins that span the full depth of cell membrane; create pores to allow a ions to pass though cell membrane; can close or open to control the entry of ions in or out of the cell
Water can move across the cell membrane via…
aquaporins
how do aquaporins work
transporter proteins that move water by diffusion
osmosis
net movement of water or a solvent through a semipermeable membrane
semi-permeable membrane
surface that blocks the passage of a type of material but not the other; a surface the blocks the movement of a solute but allows unrestricted movement of water
why does osmosis occur
differences in the concentration of solutes in and out of the cell
osmolarity
measure of a solution’s total solute
concentration
tonicity
capability of a solution to modify the volume of cells by altering their water content
active transport
movement of molecules or ions across a cell membrane from a region of lower to higher concentration; requires ATP
bulk transport
type of transport that moves very large materials, cells and cellular components across the cell membrane
how does endocytosis work
Cell membrane folds inwards (invaginates) to surround the material -> pocket pinches of from cell membrane -> vesicle forms -> material enters the cell
endocytosis
process by which a cell internalizes (takes in) a material from the external environment
phagocytosis
process by which a cell takes in large particles or other cells by engulfment
* Vesicle/vacuole will fuse with
lysosome to digest contents
pinocytosis
process by which liquids are ingested by cells
exocytosis
process by which a cell expels a material to the external environment
how does exocytosis work
A material bound for secretion or removal from the cell is surrounded by a vesicle -> vesicle fuses with the cell membrane -> material leaves the cell
