IB BIO 2 Unit 4: Cell Biology

Cell membrane

selectively permeable, lipid bilayer embedded with proteins

cell well

organelle containing cellulose fibers

nucleolus

organelle containing loops of DNA that code for ribosomal subunits and rRna

microtuble (on quiz)

component of the cytoskeleton acting as a scaffolding to maintain shape and anchor organelles

actin filaments (microfilaments)

component of the cytoskeleton allowing cell motility and cell division

tonoplast

large water filled vacuole membrane found in plants cells providing support

ribosome

most numerous organelle, assemble amino acids into proteins

smooth ER

a network of tubes and channels invilved in the synthesis of lipids as well as detoxification in the liver, free of ribosomes

golgi complex

stacks of flattened sacs which modify and package cell products

peroxisome

vesicle containing hydrolytic enzymes which break down purines producing hydrogen peroxide as a by product

lysosome

vesicle containing hydrolytic enzymes which break down proteins, carbos, and lipids, found in digestive cells as well as white blood cells

mitochondria

organelle containing cristae which perform cell respiration, have their own DNA

plastid

organelles which store substances such as pigments and starch

cilia

provide locomotion, composed of 9 pairs of fused microtubles in a ring around in the center

centriole

composed of 9 triplet microtubles in a ring, seem to organize the spindle fibers during cell division

chloroplast

organelle where photosynthesis occurs, also contains its own DNA

glycoprotein

Substance found in cell membrane responsible for the cell recognizing and binding to other cells

cholesterol

substance found in cell membrane maintaining the fluidity of the membrane even in cold temperatures

cell fractionation

process allowing a biologist to separate out cell components

TEM microscope

microscope that allows magnification up to 1 million times

which of the following is present in mitochondria but not in chloroplasts?

a. DNA and ribosome

b. outer and inner membranes

c. cristae

cristae

which organelles have a transport function?

a. ribosome and golgi body

b. golgi body and endoplasmic reticulum

c. mitochondrian and endoplasmic reticulum

d. mitochondrian and ribosome

b. golgi body and endoplasmic reticulum

what are organelles?

a.small structures in the cytoplasm of a cell found near the nucleus

b. membrane bound structures found inside all cells that have specific functions

c. discrete structures found inside all cells that have specific functions

specialized cells inside an organ that have one function

c. discrete structures found inside all cells that have specific functions

what is essential for diffusion?

concentration gradient

during endocytosis, what change will most likly occur in the plasma membrane of a cell?

it will form vesicles

What is facilitated diffusion?(THE CORRECT ONE)

The passive movement of a particle across a cell membrane via a channel protein.

cytoskelaton

gives shape, support, facilitates movement through filaments

microtuble

hollow tubes, maintenance of cell shape, cell motility (cilia/flagella).chromosome movements in cell division (spindle fibers), organelle movements

microfilaments

maintenance of cell shape, changes in all shape, muscle contraction, cytoplasmic streaming, cell motility, cell division, CLEAVAGE, 2 intertwined strands of actin each a polymer of actin subunits

cortex (outer cytoplasm)

gel with actin network

inner cytoplasm

sol with actin subunits

unsaturated fats in bilayer

prevent tight packing, more fluid. (usually liquid cant solidify). if you live in colder climates u have a higher % of unsaturated fats in ur body

cholesterol in cell membrane

restrain movement of lipids at higher temps, if too fluid membrane is less able to control what substances pass through, shape helps curve into concave shapes and forms vesicles. colder temps hinders tight packing (solidification)

O2 and CO2

move in and out easily through the phospholipid bilayer because they are non polar

aquaporin

water channel, water is also small enough to pass through phospholipid bilayer despite being hyrdophilic

plasmolysis

cell dehydration

diffusion

high to low equilibrium

permeable

allows to go through membrane

osmosis

movement of water

hypoosmotic

lower solute concentration, more water on outside

turgor pressure

The pressure that water molecules exert against the cell wall

lysed

exploded

isoosmotic

the movement of water is equal in both directions.

hyperosmotic

solution with a greater concentration of solute. less water on outside.

passive transport

the movement of substances across a cell membrane without the use of energy by the cell. high to low

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference (low to high)

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels. (polar and hydrophilic moves through protein)

carrier protein

a protein that transports substances across a cell membrane. has a specific shape

integral protein

A transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane (or lining the channel in the case of a channel protein).

peripheral proteins

bound to the surface of the membrane

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

examples of active transport

liver and intestine absorbing nutrients and sugar.

root cell absorbing minerals.

kidney absorbing toxins/urea from blood

Cotransporter protein

A protein in a cell membrane that allows movement of one molecule when linked to the movement of another molecule in the same direction by active transport.

endocytosis

engulfing molecules too big for diffusion

Phagocytosis

engulfing of large particles (solid)

Pinocytosis (THE CORRECT ONE)

process by which a cell takes in liquid from the surrounding environment

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

exocytosis

lose molecules too big for diffusion (opposite of endocytosis)

the movement of molecules from an area of high concentration to low concentration is called ___________

diffusion

if this movement is aided by a membrane protein it is called ____________ _____________

facilitated diffusion

the movement of water through a semi-permeable membrane is called _________

osmosis

the shrinkage of a cell due to the loss of water is called _________________

plasmolysis

the pressure of water exerted against the cell membrane and wall of a plant cell is called _________ pressure

turgor

in a hyperosmotic solution a cell would _______ water

lose

in an isoosmotic solution a cell would

have an equal amount of water on the inside and outside. (equilibrium)

a white blood cell's job is to engulf large solid pieces of bacteria and debris. this is an example of what type of endocytosis?

phagocytosis

the movement of molecules against the concentration gradient (low to high) is called _______ _________, this requires the cell to expend _______

active transport, ATP

describe how the structure of the membrane allows the formation of vesicles.

membrane is fluid and can change its shape;

phospholipids can move back and forth;

not very much bonding between the tails;

unsaturated fats help maintain fluidity;

cholesterol helps make more flexible;

A key event in the origin of life was the formation of a membrane that separated the contents of primitive cells from their surroundings. why was this so critical?

important in separating the contents of cells from their surroundings to protect them from any harmful materials. they give the cell structural integrity as well

why is the secondary wall of a plant cell inside the primary cell wall? where is the cell membrane in relation to the two cell walls? what makes a cell wall strong? what are it's functions?

secondary wall is inside the primary cell wall because it is made from the inside out. the cell membrane is inside both of them. cell wall contains cellulose and provides structural support, protection and maintains turgor pressure

on the basis of what you know of the functions of each of the organelles what would you expect to find most prominently in each of the following cell types: muscle, sperm, green leaf, and white blood cells?

muscle- mitchondria, microfilaments, ribosomes

sperm- nucleus, flagella, microfilament, microtubules

WB- lysosomes, microfilaments

green leaf- chloroplast, plastids, vacuoles

vinblastine is a drug that interferes with the assembly of microtubules. It is widely used for chemotherapy in treating cancer. suggest a hypothesis to explain how this slows tumor growth by inhibiting cell division.

microtubles are important in cell division, therefore, if the cell cant divide you can slow the tumor cells growth

summarize the major differences between the compound light, transmission electron, and scanning electron microscopes. comparing resolving power of each.

compound- uses glass lenses and light, able to study living cells. inexpensive. resolution: 200 nanometers

TEM- electrons guided by magnetic lenses in a vacuum. high magnification power (1,000,000X) view sections in 2-D. kills cells, expensive and time consuming.

resolution: .2 nanometer

SEM- electrons guided by magnetic lenses in a vacuum. scatters electrons to obtain a 3-D view of cell surface. good magnification (250,000X)

resolution:10 nanometers

arrange the following in order from smallest in diameter to largest. what determines the lower and upper size limits of eukaryotic cells?

molecule, cell membrane, virus, organelle, bacteria, eukaryote cell

explain the properties of phospholipids help to maintain the structure of the cell surface membrane

hydrophilic head point outward; hydrophobic tails form a lipid bilayer; forms a phospholipid bilayer; ions and polar molecules cannot pass through hydrophobic barrier; helps the cell maintain internal concentration and exclude other molecules

explain the importance of surface to volume ratios in cells

rate of transport of materials across membrane; energy or heat is a function of surface area; rate of metabolism is a function of mass to volume ratio; as size increases the ratio between SA and volume decreases; causing problems in transport or rate of exchange

compare an animal eukaryotic cell vs a prokaryotic cell with the help of a diagram (plant vs animals???)

similarities: both cell membrane, nucleus, mitochondria, ribosomes, lysosomes, golgi bodies, rough and smooth ER, cytoskeleton, vesicles

differences: plants have chloroplasts, other plastids, central vacuole with tonoplast. animals have centrioles, may have flagella/cilia wheras plants usuallu do not. animals more irregularly shaped

imagine a pouch with a selectively permeable membrane containing saltwater solution. it is immersed in a dish of fresh water. which way will the water move? if you add salt to the water in the dish, how will this affect water movement? what living systems exist under analogous conditions? how do you think they maintain water balance?

water will move into the pouch if you add salt water it will move slower until equilibrium is reached. protozoa in fresh water deal with this problem by having a contractile vacuole

when you forget to water house plants, they wilt and the leaves and sometimes the stems become very limp. what has happened to the plants to cause this change in appearance and texture? within a few hours you water them they resume their normal, healthy appearance. what has occured within the plants to cause this restoration. sometimes, if you wait to long to water they never revive. what has happened?

plants wilt when they lose turgor. osmosis of water into hypertonic cells to restore turgor, if severe water loss occurs you have plasmolysis and the cell dies

What limits the passage of water and other polar molecules and ions through the cell membrane? how do such molecules get into and out of the cell? describe 4 possible routes.

water and polar molecules have limited passage through the membrane because the memrane is lipid in nature. they can enter through tiny openings in the cell lipids. small ions and large polar molecules move through by transport proteins, endocytosis,

the first step in the "tasty spuds" recipe says to "soak thin slices of raw potato in cool water for 30 minutes" the 2nd step says to "saute the drained potato slices in margarine over a low flame, seasoning with salt as they cook". what would happen if they soaked the raw potato slices in salt water instead of salting them whole cooking? will there be a difference? explain.

soaking the potato slices in salt water will cause the potato cells to undergo plasmolysis. they will shrivel and probably fry up crispier. they will also gain salt and could become too salty

if the plant cell wall or animal extracelular matrix were impermeable, what effect would this have on cell function?

cell wouldnt be able to function properly and would probably soon die, must be permeable to allow the exchange of matter between the cell and its external environment

the polypeptide chain that makes up a tight junction weaves back and forth through the membrane four times, with two extracelular loops, and one loop plus short C-terminal and N-terminal tails in the cytoplasm. what would you predict about the amino acid sequence of the tight junction protein?

parts of the protein that face aqueous regionns would be expected to have a polar or charged (hydrophilic) amino acids, while the parts that go through the membrane would be expected to have nonpolar )hydrophobic) amino acid. you would predict polar or charged aminoacids at each tail, in the region of the cutoplasmic loop, and in the regions of the two extracellular loops. you would predict nonpolar amino acids in the four regions that go through the membrane between the tails and loops

which structure is not part of the endomembrane system?

nuclear envolope, chloroplast, golgi apparatus, or plasma membrane?

chloroplast

Which structure is common to plant and animal cells?

chloroplast, central vacuole, mitochondria, or centriole?

mitochondria

which of the following is present in a prokaryotic cell?

mitochondrion, ribosome, nuclear envelope, or chloroplast

ribosome

Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the

mitochondria, ribosomes, peroxisomes, or lysosomes?

mitochondria

which cell would be best for studying lysosomes?

muscle , nerve, bacterial, or phagocytic WBC?

phagocytic white blood cell

Carbohydrates are attached to plasma membrane proteins in the ER. on which side of the vesicle membrane are the carbohydrates during transport to the cell surface?

they are on the inside of the transport vesicle membrane

How would the membrane lipid composition of a native grass found in very warm soil around hot springs compare with that of a native grass found in cooler soil? Explain.

grasses living in colder regions would have more unsaturated fatty acids in their membranes because those fats remain fluid at lower temps

grasses living in hotter environments would have more saturated fats, which would allow the fats to "stack" more closely, making the membranes less fluid and therefore helping them to stay intact at higher temps.

why is a transport protein needed to move many water molecules rapidly across the membrane?

water is a polar molecule, so it cannot pass very rapidly through the hydrophobic region in the middle of a phospholipid bilayer

how do you think a cell performing cellular respiration rids itself of the resulting CO2?

CO2 is a nonpolar molecule that can diffuse through the plasma membrane. as long as it diffuses away so that the concentration remains low outisde the cell, it will continue to exit the cell this way

if a paramecium swims from a hypotonic to an isotonic environment, will its contractile vacuole become more or less active? why?

activity of the contractile vacuole will decrease. vacuole pumps out excess water that accumuilates in the cell; this accumulation occurs only in a hypotonic environment

As a cell grows, its plasma membrane expands. Does this involve endocytosis or exocytosis? Explain.

exocytosis. when a trasnport vesicle fuses with the plasma membrane the vesicle membrane becomes part of the plasma membrane

in what way do the membranes of a eukaryotic cell vary? (hint proteins)

certain proteins are unique to each membrane

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

embedded in a lipid bilayer

which of the following factors would tend to increase membrane fluidity?

greater proportion of unsaturated phospholipids; greater proportion of saturated phospholipids; lower temp; or a relatively high protein content in the membrane

a greater proporttion of unsaturated phospholipids

which of the following processes includes all the others?

osmosis, diffusion of a solute across a membrane, passive transport, transport of an ion down its electrochemical gradient

passive transport

which of these experimental treatments would increase the rate of sucrose transport into a plant cell?

1. decreasing extracellular sucrose concentration

2. decreasing extracellular pH

3. decreasing cytoplasmic pH

4. adding a substance that makes the membrane more permeable to hydrogen ions

decreasing extracellular pH

centrioles

Cell organelle that aids in cell division in animal cells only