topic 2 cells

what is a eukaryotic

A cell that has membrane bound organelles and a nucleus

What is a prokaryotic cell

cell that does not have a nucleus or membrane bound organelles

what is an example of a eukaryotic cell

plant cell, animal cell, fungi, algi

what are the different parts of the nucleus

nuclear envelope, nucleolus, nucleus, chromatin, nuclear pores, nucleoplasm

what is the function of the rough endoplasmic reticulum

production of ribosomes and glycoproteins

what is the function of the smooth endoplasmic reticulum

synthesis of lipids and carbohydrates

what is the function of the golgi

Modifies proteins and lipids

before transporting them via vesicles.

what is the function of a lysosome

contain lysozymes that hydrolyse pathogens

what is the function of the mitochondria

site of aerobic respiration

what are the function of cristae (folds in mitochondria membrane)

increase surface area

what is the function of a ribosomes

protein synthesis

what is the difference between 80s and 70s ribosomes

80s ribosomes are larger than 70s

what is the function of a chloroplast

Site of photosynthesis

what are thylakoids

discs that contain chlorophyll

what are granum

stacks of thylakoids

what is the stroma

fluid in the chloroplasts that contains enzymes

what type of cell is prokaryotic

bacteria

what do prokaryotes cells contain that eukaryotes don't

flagella, slimy capsule, pili, nucleotide

what are bacteria cell walls made of

murein

what is the function of the slimy capsule

to help bacteria stick together

what are plasmids

small loops of DNA contained in the bacteria cell

define magnification

how much bigger the image is compared to the object

define resolution

how easy it is to distinguish between 2 points

describe the process of preparing a slide

1. a drop of water the slide

2. a the sample to the slide

3. add a dye or stain

place a cover slip over the top

does TEM show a 2d or 3d image

2d

how does a TEM work

electrons pass through the specimen

Does a scanning electron microscope produce 2D or 3D images

3D

how does a SEM work

electrons are scattered around the surface of the specimen

what is the purpose of placing a cell in a cold solution

it reduces enzyme activity

what is the purpose of placing a cell in a isotonic solution

to stop the cell bursting or shrivelling

what is the purpose of placing a cell in a buffered solution

keep a constant pH

what is homogenisation

breaking up of the cell to release organelles

Describe ultracentrifugation

1.the homogenised sample is placed in the ultracentrifuge and spun at a slow speed

2.the heavier organelles are forced to the bottom

3. the liquid at the top is the supernatant

4.it is then respun to gain the next organelle

what stage occurs before mitosis

interphase

what occurs in interphase

copying of DNA and duplication of organelles

what are the 4 stages of mitosis in order

1. prophase

2.metaphase

3.anaphase

4.telophase

what occurs in prophase

. nuclear envelops breaks down

. spindle fibres form

what occur in metaphase

.chromosomes line up down the middle

.chromosomes attach to spindle fibres

what occur in anaphase

.chromatids are pulled to opposite poles

.centromere splits

what occurs in telophase

.spindle fibres break down

.nuclear envelope reforms

what is cytokinesis

the entire cell splits in half

describe the stages of binary fission

1. DNA replicates

2. cell elongates

3. proteins line up down the centre

4. the cell is pinched and begins to split

5. newly formed membranes form two identical daughter cells

describe the reproduction of a virus

1. virus attaches to the host cell membrane and endocytosis occurs

2. RNA enters the nucleus where it is replicated to form mRNA

3. mRNA is used to synthesise viral proteins

4. viral proteins are released by exocytosis and kill the cell

what is the function of cholesterol in the membrane

regulate stability and fluidity of the membrane

what is the function of glycolipids and glycoproteins

recogonition sites

define diffusion

The net movement of molecules/ions from

an area of higher concentration to an area

of lower concentration until evenly distributed.

what molecules can be transported using simple diffusion

. small molecules

. non polar molecules

how does facilitated diffusion occur

through the use of channel and carrier proteins

what molecules can be transported using facilitated diffusion

. large molecules

. polar molecules

. charged molecules

what are the factors that affect the rate of diffusion

. temperature

. number of proteins

. diffusion distance

. surface area

. concentration gradient

why is diffusion a passive process

it does not require ATP

Define osmosis

The movement of water from an area of higher

water potential to an area of lower water

potential through a selectively permeable

membrane.

what is the water potential of pure water

0 kPa. This is the highest possible value for water potential

what happens to an animal cell in a hypotonic solution

it becomes haemolysed (bursts)

what happens to an animal cell in a hypertonic solution

it becomes flaccid

what happens to an animal cell in a isotonic solution

it is at equilibrium

what happens to a plant cell in a hypotonic solution

it becomes rigid

what happens to a plant cell in a hypertonic solution

plasmolysis (loss of water)

what happens to an animal cell in a isotonic solution

Plasmolysis

define active transport

The movement of molecules/ions in or out of a

cell from an area of lower concentration to an

area of higher concentration using ATP and

carrier proteins.

when ATP is hydrolysed what does it become

ADP and a phosphate group releases energy

what are ways that active transport can be increased

. increase the number of proteins

. increase the speed of proteins

. increase respiration

what is contained in the lumen of the small intestine

villi-microvilli

describe step 1 of co transport

1. sodium ions ar pumped out by active transport by the sodium-potassium pump

describe step 2 of co transport

2. sodium ions diffuse into the cell against the concentration gradient via sodium glucose co-transporter protein

describe step 3 of co transport

this increases the concentration of glucose in the cell

describe step 4 of co transport

the glucose diffuses out of the cell via facilitated diffusion through a protein channel

what are the 4 types of white blood cell

.phagocytes

.granulocytes

.t lymphocytes

.b lymphocytes

define antigen

any part of an organism that is recognized as foreign by the immune system

what part of the immune system are phagocytes a part of

non specific

what is the 1st step of phagocytosis

.antigens on the pathogen are recognised by the phagocyte

.the pathogen also secretes chemicals which attract the pahgocytes

what is the 2nd step of phagocytosis

the pathogen is engulfed into the phagosome

what is the 3rd step of phagocytosis

.lysosomes release lysozymes which hydrolyze the pathogen

.antigens present on the surface to active memory cells

whata are the bodies first line of defense

.skin barrier

.tears

.mucus

.acid in sweat

.blood clotting

where do t lymphocytes mature

thymus gland

Where do B lymphocytes mature?

bone marrow

what is the first stage of the T lymphocyte response

pathogen invades the organism and the antigens are presented on the surface of the phagocyte

what is the second stage of the T lymphocyte response

T helper cells bind the antigens presented

what is the third stage of the T lymphocyte response

T cell divides rapidly by mitosis

what is the fourth stage of the T lymphocyte response

. b cells stimulated to secrete antibodies

. memory cells produced

. phagocytes stimulated

what is the first stage of the B lymphocyte response

B cell processes the antigens of the pathogen and presents them on its surface

what is the second stage of the B lymphocyte response

T helper cell binds to the antigens which causes mitosis of B cells

what is the third stage of the B lymphocyte response

plasma cells and memory cells are produced

What are monoclonal antibodies?

Antibodies produced from a single group of identical B-cells

what are the uses of monoclonal antibodies

. cancer treatment

. pregnancy tests

. medical diagnosis

What is active immunity?

the immunity that results from the production of antibodies by the immune system

What is passive immunity?

Antibodies that are formed in another body but passed down for short term use (ex. breast milk)