The Cell A Flashcards
what does it mean if something is smaller than a cell
it is not alive, cell is the smallest unit of life
what is the range of cell size
8 to 100 um
if an organism is bigger does that mean their cells are bigger
larger organisms do not generally have larger cells than smaller orgsnisms, simply more cells
why are cells so small
because as cell size increases, the metabolic needs of the cell increases
-the surface area (pm) is smaller than the volume so it can’t meet the demands
what does having a smaller volume mean for a cell
less metabolic demands but also less surface area to transport materials in and out
why is cell size limited
because of requirements of homeostasis
what is the range of size for prokaryotic cells
1-10 um
how do you classify organisms in the bacteria domain
using the gram test
what are the functions of cell walls
rigidity
protection from bursting
cell wall composed of peptidoglycan (protein + carb)
what are characteristics of gram positive bacteria
stain blue/purple
have a thick peptidoglycan layer after the plasma membrane
what are the characteristics of a gram negative bacteria
stain red
have a thin peptidoglycan layer
have an extra outer membrane
do antibiotics have a harder time going through gram + or - bacteria
gram - (extra outer membrane)
what are the functions of capsule on prokaryotes
-prevents the cell drying
-helps cell adhere to things
-protects cell from white blood cells (no antigens so w.b.c. can’t recognize it as enemy)
what are three characteristics of the domain archaea
-have histones (proteins) associated with dna like eukaryotic cells
-have s layer on cell surface
-have a cell wall (no peptidoglycan)
what is the main goal of bacteria
decomposition
what is the s layer on archaea composed of
glycosylated proteins (have glucose)
what are the two major categories of organelles
membranous organelles
non membranous organelles
what are examples of membranous organelles
plasma membrane, cytoplasm, nucleus
smooth and rough ER, golgi, vesicles, lysosomes, peroxisome, mitochondria, chloroplast, vacuoles
examples of non membranous components
nucleolus, ribosomes, cytoskeleton, centrosome, cilia, flagella, cell junctions, cell wall, extracellular matrix
why is the plasma membrane important
to regulate movement in and out of the cell
the maintain the interior environment balanced (critical for cell processes and function)
what are the functions of the plasma membrane
cell adhesion, recognition, communication and regulating interior env.
what is the plasma membrane made of
phospholipid molecules
protein molecules
cholesterol
what do phospholipids do in the plasma membrane
selectively permeable
allows some substances to cross it better than others
what is the fluid mosaic model
proteins moving sideways through the plasma membrane’s bilayer
what is the difference between the cytoplasm and the cytosol
-cytoplasm is the region between the nucleus and the plasma membrane
-cytosol is the fluid substance inside the cell which contains the organelles
*cytoplasm is filled w/ cytosol
is the nucleolus membrane bound
no (its inside the nucleus and makes the ribosomes)
what does the membrane of the nucleus look like
looks like a double membrane but is actually folded over itself (nuclear envelope)
has pores to allow exchange of materials (between nucleus and cytoplasm)
what is a chromatin
loosely arranged dna and protein
what is a chromosome
tightly packed dna and histones (proteins) in x shape (46 chromosomes total)
what are the two types of endoplasmic reticulum and what makes them different
-rough ER (has ribosomes/dots)
-smooth ER
what is the ER membrane made of
-continuation of nuclear envelope
-weaves in sheets creating a network of membrane tubules and sacs (lipid bilayer) called cisternae
what are cisternae
tubules and sacs (lipid bilayer) of the ER membrane
what are the functions of the rough ER
-produce proteins (ribosomes)
-distribute proteins to other cells or organelles
-modify proteins (by + carbs or lipids)
where does the rough ER send most of its proteins
golgi apparatus
how does the rough ER modify proteins
fold into 3D shape
enzyme can modify proteins by adding carbs or lipids to them
what are the functions of the smooth ER
-synthesize and transport proteins
-enzymes detoxify poisons and drugs (liver)
-metabolizes carbs
-storage of calcium
what is the difference between smooth and rough er
rough has ribosomes attached and smooth is without ribosomes
what are the functions of the golgi apparatus
-packaging and shipping centre of molecules
-chemical modification of molecules
-synthesizes carbs
what are the characteristics of golgi apparatus
structurally similar to ER
5-20 membranous sacs (cisternae)
what is a vesicle
a hollow sphere with a membrane identical to the plasma membrane
what is the function of vesicles
store/transport chemicals around the cell
what are the two types of vesicles, who makes them and where do they go
transport (ER makes it to get proteins to golgi)
secretory (golgi makes it to go to the plasma membrane or around the cell)
what is the structure of a vessel
hollow spherical organelles, surrounded by membrane identical to PM = membrane enclosed sacs
who makes lysosomes
golgi makes them
how does a lysosome work
a vesicle that contains digestive enzymes (pH 5 so acidic) which are only active inside its membrane to prevent damaging the cell in case of leakage (cells pH is 7.2)
what are the processes lysosomes go through called
phagocytosis
autophagy
what is phagocytosis
lysosome digesting materials from outside the cell
what is autophagy
lysosome digesting organelles from inside the cell (itself)
how do lysosome digest things
engulfs them
what are the functions of peroxisomes
-fatty acid metabolism
detoxify harmful compounds (liver)
-gets rid of the hydrogen peroxide released when enzymes transfer hydrogen to oxygen (ex. phagocytosis and autophagy)
-can self replicate
what allows peroxisome to detoxify hydrogen peroxide
has enzyme that turns H2O2 to water
what are the functions of mitochondria
power house of the cell
aerobic respiration
makes ATP from glucose
converts food into energy
how many membranes do mitochondrias have and what are they made of
2 membranes that each have a phospholipid bilayer
what is the endosymbiont theory
theory that millions of years ago a cell engulfed another and developed a symbiotic relationship instead of digesting it (believed to have happened with mitochondria and chloroplast because they have the basic structure of a cell)
