chapter 3 cells

Question 1

cells

Answer 1

are the basic structural and functional unit of living organisms
vary in size, shape and function

Question 2

what are the 3 main parts of the cells?

Answer 2

plasma (cell) membrane
cytoplasm
nucleus

Question 3

plasma membrane

Answer 3

forms the boundaries of the cell –> operates the intracellular from extracellular fluid
structure is described by “fluid mosaic model”. it consist of a bilayer of fluid lipids (98%) within which are a verity of protein (2%)
lipid component of membrane is 75% phopholipids, 20% chlosterla and 5% glycolipids
phospholipids molecules are arranged in 2 layer
function as selectively permeable barrier that regulates the flow of materials into and out of the cells

Question 4

phospholipids

Answer 4

molecules that have polar heads (hydrophilic) and non polar tails (hydrophobic)
phospholipids molecules are organized with their heads facing both sides of the membrane and their tails pointing towards each other

Question 5

fluid mosaic model

Answer 5

refers to its made up of different things

Question 6

glycolipids

Answer 6

phospholipid with a sugar group attached to it

Question 7

selectively permeable

Answer 7

only some things can pass through it

Question 8

what are the two types of membrane proteins?

Answer 8

intergral transmembrane proteins and peripheral membrane proteins

Question 9

intergral transmembrane proteins

Answer 9

extend through the phospholipid bilayer. in contact with the outside and the inside of the membrane

Question 10

peripheral membrane proteins

Answer 10

are associated loosely with only one side of the membrane. don’t go all the way through they are in contact with EITHER the outside OR the inside

Question 11

what are the membrane protein functions?

Answer 11

transporter = as channels or carriers
receptor for chemical messenger (bind to something and can active or reactive the cell in some way)
enzyme that catalyze recation
marker in cell recognition
anchors to cells cytoskeleton

Question 12

membrane permeability

Answer 12

a membrane is permeable to substance that can pass through impermeable to substance that can’t
cell membranes are selectively permeable
- allow some things to pass more easily than others
usually permeable to bipolar, uncharged and small molecules
usually impermeable to ions, charged or polar molecules exception: water

Question 13

membrane transport

Answer 13

getting things across the membrane
they are a variety of mechanics for transport of substance across membranes.
in passive processes, substances move down their concentration gradients (from high to low) with no energy required from the cell

Question 14

active process

Answer 14

energy is required to move substances against their concentration gradients from low to high or for substances otherwise unable to pass

Question 15

pass transport- diffusion

Answer 15

net movement of molecules from an area of high to an area of low until equilibrium is reached

Question 16

how is rate affected?

Answer 16

temperature
particle size- (smaller particles move faster, larger particles move slower)
[] gradient- the bigger the difference between the two areas the faster the reaction
surface area- smaller are going to decrease (more traffic). larger are is going to increase because you go faster.
distance - shorter distance the rate will be faster

Question 17

what are the two types of diffusion?

Answer 17

simple
faciliated

Question 18

simple diffusion

Answer 18

non polar and lipid soluble substances diffuse directly through the lipid bilayer eg. CO2, O2, fat soluble vitamins (A D E K)

Question 19

facilitated diffusion

Answer 19

polar and charged molecules require transmembrane proteins as carriers or use ion channels to move through the lipid bilayer. eg. glucose, amino acids, ions

Question 20

passive transport

Answer 20

energy is not required

Question 21

passive transport- OSMOSIS

Answer 21

net movement of water from an area of high [water] to an area of low [water] though a semipermeable membrane, until equilibrium is reached.
similar to diffusion but this is strictly for water. during osmosis water can pass through the membrane, polar molecule bc the electrons are shared unequally. can go through the phospholipid gaps. the other way it can get through is through aquaporins dedicated protein channels to allow only water to pass through

Question 22

osmotic pressure

Answer 22

the ability of a solution to attract or draw in water
the greater the # of solute particles in a solution, the greater the osmotic pressure.
more dissolved particles (solute) in a solution, the less space for water
the greater the tendency to draw in water

Question 23

active transport

Answer 23

substances cross the membrane by moving against their concentration gradient and energy is required

Question 24

primary active transport

Answer 24

energy from ATP hydrolysis (break ATP, breaking off the last phosphate of and release all of the energy to form ADP + a free floating phosphate) changes the shape of a transporter protein and it “pumps” a substance across the membrane
eg. Na+\K+ pumps transport Na+ out of the cell and K+ in.
40% of the ATP the cell uses is for primary active transport

Question 25

secondary active transport

Answer 25

coupled transport pf 2 molecules using energy supplied by an ion gradient, rmaintained by a primary active transport pump
eg. Na+ is co-transported with glucose
its indirectly using energy from ATP. Na ions that were being pumped out by the sodium potassium pump creates a build up of sodium on the outside which then wants to float back in. the secondary active transporter goes “oh there is already a build up of sodium that is naturally gonna flow down its concentration gradient ill just piggy back something along with the sodium and bring it into the cell at the same time”. it is capitilizing on the result of the primary active transporter.
energy stored in a Na+ or H+ concentration gradient is used to drive other substances into the cell

Question 26

antiporter

Answer 26

opposite directions

Question 27

symporter

Answer 27

same direction

Question 28

vesicle transport

Answer 28

used for large particles, macromolecules and fluids.
vesicle is a bubble of membrane within that bubble is something like hormones, neurotransmitters or waste, etc
exocytosis
endocytosis

Question 29

exocytosis

Answer 29

moves a packed vesicle out of the cell by fusing with the cell membrane and releasing its contents.

Question 30

endocytosis

Answer 30

moves materials into the cell by forming a vesicle
an example of this is phagocytosis (cell eating)

Question 31

cytoplasm

Answer 31

cellular material between the palms membrane and the nuclear

Question 32

what are the two major elements of cytoplasm?

Answer 32

-cytosol
-organelles

Question 33

cytosol

Answer 33

fluid surround the organelles
is 75-90% water with dissolved and suspended components
is the site of many chemical reactions required for a cells existence

Question 34

organelles

Answer 34

specialized strictures that have specific functions necessary for the life of the cell (“organ of the cell”)
most organelles are membrane-bound

Question 35

what’s the point of having membrane bound organelles?

Answer 35

used to keep them separate so they can perform their functions without being affected in the cytoplasm.
cytoskeleton, ribosomes are organelles with membranes

Question 36

name 6 organelles

Answer 36

mitochondria
ribosomes
endoplasmic reticulum (ER)
Golgi complex
lysosomes
cytoskeleton

Question 37

mitochondria

Answer 37

3/4 of cellular respiration takes place here
oval, elongated organelle
has an outer membrane and an inner folded membrane (cristae- electron transport chain takes place here)
inner fluid is called the matrix
function- produces most of the cells ATP
mitochondria has its own DNA called mitochrian DNA, taken from your mother.

Question 38

ribosomes

Answer 38

tiny organelles composed of rRNA and protein (not membrane bound)
consists of 2 subunits (created in the nucleolus)
can be “free” ribosomes in cytoplasm or can be attached to the (rough) ER
function: involved in protein synthesis, its the main machinery that helps to build proteins

Question 39

endoplasmic reticulum

Answer 39

network of membrane-enclosed channels (cisternae) continuous with the nuclear membrane
two types;
rough ER
smooth ER

Question 40

Rough ER

Answer 40

has ribosomes attached to the external surface
function: protein synthesis and transport of proteins for export

Question 41

smooth ER

Answer 41

continuation of RER but lack ribosomes
function: site of lipid and steroid synthesis and detoxifies drugs

Question 42

Golgi complex

Answer 42

series of flattened sacs with bulging ends
function; to modify, sort and package proteins for various destination in cells
One side (cis or entry face) receives transport vesicles from the ER
Contents are modified as they travel from cis face to trans face (exit side) of Golgi.
Contents are packaged into vesicles at trans Golgi
There are 3 zones, flattened membrane disks, one side is cis face it bring proteins and are packaged in vesicles and are absorbed from the cis face as they move through they are being modified at the other side of “pancakes” they are let go.
Secretary vesicle, release things outside the cell.
Transport vesicle bring digestive enzymes to lysosomes.

Question 43

lysosomes

Answer 43

membrane-bound sacs formed by golgi
contain powerful acid hydrolyses (digestive enzymes)
function; digests substances transported into the cell or digests cellular debris

Question 44

cytoskeleton

Answer 44

a network of protein filaments that extend throughout the cytosol
function: provides structure and support and also aids in the movement of structure within the cell

Question 45

nucleus

Answer 45

usually round and found towards the centre of the cell
most cells have a single nucleus
contains jelly-like nucleoplasm
bounded by a double membrane

Question 46

anucleate

Answer 46

no nucleus (red blood cells)

Question 47

multicleate

Answer 47

more than one nucleus per cell (eg. skeletal muscle cells)

Question 48

nuclear structures

Answer 48

the nucleus has three structures:
nuclear envelope
nucleoli
chromatin

Question 49

nuclear envelope

Answer 49

is a double membrane that controls the movement of substance between the cytoplasm and nucleus (eg. messenger RNA during DNA replication)
lipid bilayer similar to plans membrane
outer membrane is continuous with RER
nuclear pore

Question 50

nuclear pore

Answer 50

a circular ring of protein extending through the nuclear envelope. it allows for movement between cytoplasm and nucleus

Question 51

nucleoli

Answer 51

nucleolus (singular), nucleoli (plural)
dark stains round structure(s) found in the nucleus
not enclosed by a membrane
function: produce ribosomes

Question 52

chromatin

Answer 52

granular, thread-like material composed of DNA and protein of a non-diving cell
threads will become chromosomes when the cell is diving
function; consist of genes which control cellular structure and direct cellular functions by providing instructions for protein synthesis

Question 53

cell division

Answer 53

process by which cells reproduce themselves
types types of cell division occur;
somatic cell division
reproductive cell division

Question 54

somatic cell division

Answer 54

a body cell undergoes nuclear division to produce a new body –> MITOSIS

Question 55

reproductive cell division

Answer 55

a germ cell undergoes nuclear division to produce a gamete
–> MEIOSIS