Biology Exam 2

what does cell volume represent

Demand

what does the cell surface represent?

the supply

For a cell to survive what have to be greater than what?

The supply ( surface area) has to be greater than the demand (volume of the cell)

What is the reason for cells to stay so small?

As cells get larger, their volume and demand increases faster than their surface area or there for supply. So they stay small to maintain a good ratio.

Prokaryotic cells are smaller in size but are dominant in what aspects

Biomass and diversity

What are the cell walls of eukaryotic cells made of?

peptidoglycans also known as sugar proteins

what blocks the productions of peptidoglycans in eukaryotes?

antibiotics

What is a distinctive feature in eukaryotes?

compartmentalization due to the internal membrane system

Inside a the nucleus, what are functions?

storing of genetic information, assemble of ribosomes, where RNA is produced through transcription

what is chromatin and where is it found?

Chromosomal DNA that bound to DNA binding proteins in order to fit into the nucleus

what all is in the nucleus?

the nuclear envelope, nuclear pores, chromatin, and nucleolus

describe the nuclear envelope.

It is a double lipid bilayer which separates it into an inner and outer layer. The outer layer is connecter to the smooth and rough ER. there is also intermembrane space between the inner and outer bilayer.

what is the specific place in the nucleus called that ribosomes are assembled

nucleolus

In general, describe the endoplasmic reticulum.

network of interconnected tubules, the tubules are composed of lipid bilayer and contain a space inside called the lumen

what is the lumen

the space inside the tubules within the endoplasmic reticulum

how is the endoplasmic ER connected

both the smooth and rough ER are connected to each other as well as the outer layer of the nuclear envelope.

what are the functions of the smooth endoplasmic reticulum

site of lipid synthesis, desaturation of fatty acids, site of cholesterol synthesis, some carbohydrates such as glycogen are synthesized here

describe what happens withing the rough ER

proteins are synthesized by the RER-associated ribosomes

what could happen to the protiens created in the RER

what is the structure of the golgi apparatus?

-flattened tubes(sacs)

-walls of tubules

-inner liquid matrix

-independent structure, not connected to anything

what does the cis face of the golgi apparatus do?

receives transport vesicles from the ER

what does the trans face of the ER do?

transport vesticles exit golgi

what does the golgi apparatus do?

proteins and molecules are modified, sorted, and then released in vesicles

Exocytosis

materials are removed from the cell

what is endocytosis

when material is either taken into the cell through specific or non specific

how are materials transported through a specific process of endocytosis

the plasma membrane creates a endocytic vesicles that then fuses with lysosomes

what all can lysosomes degrade?

nucleic acids, carbohydrates, lipids, proteins

are lysosomes acidic or basic?

Lysosomes are acidic because their digestive enzymes can only function in acidic conditions.

what is the range of the internal ph of a lysosome in order for the digestive enzymes to function?

4.5-5.0

how do lysosomes turn acidic?

when they fuse, protiens pump protons into the lysosome which lowers the internal pH

what does the lysosome originate?

originates from the trans face of the golgi apparatus

what are the functions of the lysosome

to digest materials coming into the cell, and to digest worn out materials from inside the cell, also hydrolyze polymers

What are the two phases of the lysosome?

primary lysosome- where the the lysosome has not fused

secondary- when the lysosome fuses and the digestion happens

what is the tuberculosis and why is it such a big problem?

it is a bacteria that interferes with the fusing of the endocytic vesicle and the lysosome, therefore preventing the destruction.

Describe the structure of mitochondria

consists of a double lipid bilayer that has a smoother outer and an extremely enfolded interior called cristae. The liquid inside these cristae is called the matrix

what is the function of the mitochondria

energy metabolism, or ATP production

What is the origin of the mitochondria?

the mitochondria can only come from pre-existing mitochondria, it is also endosybiosis theory

what is the endosymbiosis theory

that organelles inside eukaryote have evolved from prokaryotic cells

what is the relationship between the photon wavelength and photon energy?

as photon wavelength increases photon energy increases

what is the function of chloroplasts?

site of photosynthesis, light is converted to chemical energy

describe the structure of the choloroplast

double lipid bilayer, thylakoid, granum, and stroma

what are the thylakoid, granum, and stroma

the thylakoid is a layer that consists of a single membrane disk, the granum is a stack of thylakoids, the granum is the liquid surrounding the granum

decribe the structure cytoskeleton

is a network of multiple type of proteins inside a cell

what is the function of the cytoskeleton?

it provides structural support, aids in transport in cells, and it helps mobile cells move

what is the structure and function of extracellular fluid

network of multiple types or proteins OUTSIDE the cell. provides structural support, glues cells to organs, and helps cells communicate

what are the functions of the Plasma membrane?

the plasma membrane acts as a selective barrier that is dynamic and can change based off of the chemistry and the molecules associated with it

explain the discovery of membrane struture

in 1924 Gorter used uniform RBC and measured their surface are, then collected the phospholipids and set them in a liquid buffer where they formed floating matter which allowed Gorter to calculate that the surface area of phospholipids were double that of the RBC

what is inside the plasma membrane?

transmembrane proteins, peripheral proteins, cholesterol and, polysaccharides attached to the outside

what does the fluid mosaic model mean

it shows that membranes are fluid structures

what did the cell fusion experiment do?

fused to cells to show fluidity of cell membranes

the cytoskeleton and the what are both attached to the plasma membrane

the extracellular membrane

explain photo-bleaching experiments

shows fluidity how molecules diffuse back into an area after being hit by a laser. the more intense the laser the longer it took for molecules to diffuse back into the space

what happens when the membrane becomes too fluid?

as starts fail as a barrier and the structure of the cell falls apart

what happens when the membrane becomes too solid

the transmembrane protein can no longer flex meaning cells have a harder time responding to the environment, this shuts down signaling and cell transport

what two things happen simultaneously in order to fix a too fluid membrane

the fatty acids chains become more saturates which causes them to fit together more tightly, they also make fatty acids longer which increase the surface area

what two things happen the fatty acid chains of the phospolipids of the membrane when it is too solid

turn the fatty acids less saturated and shorter in order to make them less compact and take up less space

what are some outside factor that effect the fluidity of the membrane

external tempreatures

what tempreature makes the membrane more fluid?

higher temperature

what happens when the membrane is exposed to cold tempreatures

the membrane becomes more solid

describe the structure of cholesterol and where it is found

is amphipathic, has a hydrophilic head and a hydrophobic ring with a hydrocarbon tail and is found inside the plasma membrane of only eukaryotic cells

what does cholesterol do for the plasma membrane

helps act as a buffer to regulate the fluidity within the plasma

what does cholesterol do in order to maintain the fluidity of the plasma membrane

slows down how fast the fatty acids compact together

how does cholesterol help to maintain solidity?

the hydrophobic steroid ring partially immobilizes the fatty acids

descibe what is permeable vs unpermeable to the membrane

permeable to non-polar, hydrophobic molecules , it is less permeable to small polar molecules(water,ethanol), not permable to to large polar molecules (sodium, glucose)

what is the difference between active and passive transport

passive is the transport from high concetration to low concentration that doesnt require energy, active transport requires energy and goes against the concentration gradiant from low to high

what are the two types of diffusion

simple anf facilitated

what is simple diffusion and what are the requirements for it to happen?

can only happen if the PM is permeable to the molecule and if there is a difference in concentration gradient, it doesnt require any energy or transport proteins

explain facillitated diffusion

can be regulated by cells, transports molecules that cannot pass through membranes by themselves, requires transport protiens

what are the two types of transport protiens used in facilitated diffusion

channel and carrier

explain channel proteins

like tunnels where molecules dont have to make physical contact, the concentration determines what direction the channel flows, there are open and gated channels

explain carrier proteins

molecules must bind to the proteins, which alters the shape of the protein to let the molecule diffuse into the cell

what are the types of carrier proteins

uniporters- can only transport one type of protein

symporters- have 2 binding sites and can transport two molecules the same direction at the same time

antiporters- 2 types of molecules go in opposite directions at the same time

what is the difference between carrier an channel proteins

they have different kinetics, rates of transport

describe the different rates of transport between channel and carreir protiens

channel proteins have a very liner rate meaning as the concentration increases, so does the rate at which things diffuse. carrier proteins become more saturated because there is a point of saturation where the carrier proteins cannot add any more bonding sites as the concentration increases

describe active transport?

used to build up a concentration, uses energy and carrier protiens

what are the characteristics of life

uses energy to maintain levels of organization, respond to environment through maintianing homeostasis, growth and metabolism, reproduction, evolving, composed of one or more cells

what are some of the characteristics that made the mitcochondira and chloroplast fall under the endosymbiotic theory?

reproduced through binary fission, have circular chromosomes/DNA, have their own ribosomes that match prokarytotes ribosomes structure

what are all the ways a too solid plamsa membrane effects the cell?

slows membrane transport because the transmembrane protiens cannot flex, and effects signaling proteins which means it cannot adapt to the environment

what type of proteins in membrane transport are seen as saturated?

active or carrier transport proteins

why cant channel proteins in passive transport become saturated

because there is linear kinetics, meaning the more molecules, the more are allowed through as oppsoded to carrier protiens which are limited to the amount of binding sites

What do facilitated diffusion and active transport have in common?

why both use carrier proteins

what type of transport proteins does facilitated diffusion use

both carrier and channel protiens

what are two things that are present in ALL prokaryotic and eukaryotic cells

cell membrane and ribosomes

what are the components of prokaryotes?

cellular membrane, DNA in sphere chromosomes, ribosomes, cytoplasm

how does cholosteral effect the plasma memebrane at lower tempreatures

cholesterol interferes with the packing pf phospholipids which makes the plasma membrane more fluid

how does chlolesterol effect the plasma membrane at higher tempreatures

cholesterol limits the phospholipid mobility which makes the plamsa membrane less fluid and more solid