cells Flashcards

Question

virus cell function of... rna

Answer 1

used for dna formation

Answer 2

protests the rna

Answer 3

fuses with cell membrane ( phospholipid ) allows entry to host cell

Answer 4

identifies host cell

Answer 5

makes dna from rna template

Answer 6

How many times larger the image is compared to the object

Answer 7

The minimum distance between 2 object where they can still be viewed separately Optical = determined by wavelength Electron = determined by the wavelength of the beam of electrons

Answer 8

- beam of light creates the image - lower magnification - poorer resolution = light has longer wavelength - colour images - can view living samples - small organelles non visible due to bad resolution

Answer 9

- beam of electrons is considered to create the image - electromagnet is used to condense the beam - higher resolution = shorter wavelength - black and white ( had to be stained ) - sample must be in a vaccume bc electrons are absorbed by air

Answer 10

- thin specimens, electrons pass through - some are absorbed - 2D image

Answer 11

- Specimens can be any width - electrons are scattered - produces 3D image

Answer 12

Mag = image / object

Answer 13

- inside optical microscopes = scale - can be used to measure size of object but has to be calibrated when magnification has changed

Answer 14

A stage micrometer is used to calibrate 2mm long Sun division are 10 micrometers apart

Answer 15

- to isolate different organelles so they can be studied - they are broken open to release the contents and organelles are seperated - enables individual organelle structure and functions to be studied

Answer 16

Must be prepped in: Cold ( reduces enzyme activity) Isotonic ( prevents osmosis causing cells to shrivel and burst ) Buffered ( PH buffer prevents cell damage)

Answer 17

Homogenisation - must be broken open using a blender in the specific conditions and filtered Ultracentrifugation - filter is spun at different speeds in a centrifuge = organelles separated

Answer 18

- centrifuge spins and the centrifuge forces causes dense at the bottom - each time the supernatant ( liquid ) is removed leaving a pellet of organelles

Answer 19

Allows lipid soluble substances to move through Selectively partially permeable

Answer 20

Makes structures more rigid Reduces lateral movement

Answer 21

Cell recognition Allows attachment to other cells

Answer 22

Cell recognition Allows attachment to other cells Maintains stability

Answer 23

Transfer ions and water quickly through the membrane

Answer 24

Changes shape in order to move molecules across the membrane

Answer 25

passive movement of mollecules from a high to low conc till evenly distributed

Answer 26

diffusion pathway surface area temp conc gradient size of mollecule pressure

Answer 27

diffusion occours using either a carrier or a channel protein, allowing mollecules to move down conc gradient passively

Answer 28

affected by the amount of peroteins - when they are saturated the rate will plateau

Answer 29

movement up a concentration gradient via carrier proteins, with the use of energy from ATP from respiration

Answer 30

1. sodium actively transports out of the cell into the blood - ATP 2. low conc of sodium maintained in cell 3. high sodium ( gut ) is co transported with either an amino acid or protein via a co transport protein 4. falicitated diffusion occours where the glucose/amino acid moves to the blood

Answer 31

type of conc gardient if ATP is used if a protein is used

Answer 32

- No visible chromosomes G1 - protein synthesis, growth, differentiation 20DNA S - cell replication 40DNA G2 - cytoskeleton breaks, error checking ( proof reading enzymes ) if bad = apoptosis = suicide 40DNA

Answer 33

- chromosomes coil and become visible - 2 sister chromatids join via their centromere - spindle fibres form and extend

Answer 34

- chromasones line up at equator - attach to spindle fibres at centromere

Answer 35

- the centromeres divide - sister chromatids are pulled to opposite poles

Answer 36

- spindle fibres break down - chromosomes uncoil becoming chromatin

Answer 37

- non polar molecules - lipid based molecules - gasses - non charged - small

Answer 38

Endocytosis - engulfing molecules from outside with a vesicle Exocytosis - large molecules transported out of cell

Answer 39

Surface area x conc gradient —————————————— Diffusion pathway length

Answer 40

- conc gradient - number of carrier / channel proteins

Answer 41

- Amount of carrier proteins - Amount of ATP from aerobic respiration

Answer 42

They are disease causing microorganisms which have antigens triggering immune response

Answer 43

Foreign molecules usually proteins that trigger immune response

Answer 44

Physical barriers Phagocytosis

Answer 45

- phagocyte is attracted via chemotaxis to antigen and engulfs viruses - phagosomes fuse with lysosomes, releasing lysozymes - these hydrolyse and destroy the pathogen - antigens presented at cell membrane - waste material removed by exocytosis

Answer 46

- cell mediated response ( T Cells ) - humeral response ( B cells )

Answer 47

Cells in mitosis / total number of cells

Answer 48

Growth and repair of multicellular orgnainsms Repair tissues Replaced damages cells Asexual reproduction Production of identical cells

Answer 49

A group of specialised cells working together toe perform the same function, often from the same origin

Answer 50

- circular DNA replicates once - plasmid dna replicated multiple times - DNA moved to opposite poles - cell membrane grows between and pinches inwards - cytoplasm divides in 2 - cell walls form leaving 2 identical daughter cells

Answer 51

( 30 mins, only can function using hose energy ) - attachment = the antigens attach to host cells - entry = virus forms a hole in membrane, injecting nucleic acid - synthesis - nuclaic RNA synthesised into New viral proteins and nuclaic acid - assembly - new viruses made in host cells - release - cell bursts ( lysis ) releasing the viruses

Answer 52

- Mutation to the genes that regulate mitosis , leads to uncontrolled cell division - mutated cells mostly die - some survive and clone themselves resulting in tumours

Answer 53

They grow constantly and expand in size Benign tumours - grow slowly and compact Malignant tumours - grow rapidly and spread

Answer 54

Often involves killing dividing cells by blocking cell cycle When cell division is slowed or stopped = cancer growth slowed or stopped

Answer 55

- Prevents DNA replication - Interferes with spindle fibre formation

Answer 56

Drugs disrupt cell cycle of normal cells but are more affective against rapidly dividing cells Hair producing cells = rapid, explaining hair loss

Answer 57

- T helper cells have complimentary receptors to antigens - stimulate phagocyte to engluph - stimulate Mitosis and Cytotoxic cells to destroy infected, memory cells are produced - B cells with complimentary receptors are triggered to divide by mitosis into plasma cells - these form antibodies to destroy - the B cells become memory cells which can divide and destroy faster

Answer 58

- 2 light chain - 2 heavy chain - antigen bonding site - constant region - variable region

Answer 59

- each antibody can attach to 2 bacterial cells as they have 2 binding sites - caused the bacteria to clump together GOOD BECAUSE : - phagocytes can engulf more cels at once - prevents the spread of toxins by immobilising the pathogens - blocks the attachment proteins

Answer 60

Contains the appropriate antigens which trigger immune responses

Answer 61

Human immuno deficiency virus HIV affects the immune system ( T cells ) leading to the acquired immune deficiency syndrome ( aids ) Transported = bodily fluids

Answer 62

- lipid envelope - capsid - 2 RNA strands - reverse transcriptase - attachment proteins Belongs to the group retroviruses They use RNA to synthesise DNA via reverse transcriptase

Answer 63

1. Has attachment proteins, binds with complimentary T helper receptors 2. The virus fuses and inserts RNA and reverse transcriptase 3. Viral DNA is formed using host cell and reverse transcriptase 4. New viral RNA produced along with associated proteins 5. HIV formed and emerged from T helper cells 6. T helper destroyed

Answer 64

- HIV = virus and AIDS is a condition caused by HIV - Can detect HIV through antigen detection - can detect aids via symptoms and white blood cell count

Answer 65

- pathogens can change their surface antigens to a different type, memory cells wont recognise the pathogen when infected the second time. Meaning another primary response

Answer 66

- first time encountering an antigen - creates complimentrory memory cells - plasmea cells produce antibodies

Answer 67

- second encounter with antigen - Already containing memory B cells - They divide by mitosis, they fastly divide to plasma cells, means antibodies produced in large quantities

Answer 68

- channel proteins - temperture ( changing the tertiary structure ) - PH -Concentration gradients

Answer 69

The passage of whater froma region of high water potential to a Lower one through a partially permeable membrane

Answer 70

plant - water moves in via osmosis and the plant cell becomes turgid animal - water moves in, due to not having a cell wall the cell cannot support the extra water therefore it bursts and expericences lysis

Answer 71

water is free to move in and out (incipient plasmolysis)

Answer 72

when water is moved out of the cell it looses mass and becomes flaccid experiencing (crenation) in a plant cell the protoplast pulls away from cell membrane

Answer 73

Kpa or Mpa measured in neg numbers most concentrated = 1 the more negative the number the less concentrated

Answer 74

pressure potential+solute potential=water potential

Answer 75

hypertonic - lower water potential then in the cell ( moving out ) isotonic - solute is the sme hypotonic - low solute, higher water potential outside the cell ( water moves in )

Answer 76

top= water moving into the cell as it has a higher water potential outside bottom=whater moving out of the cell as is has a lower water potential outside ( plasmolysis)

Answer 77

all complimentory to the same antigen

Answer 78

- antigen injected into the mouse - B cells = plasma = antibodies, from spleen -mixed with tumor cells = hybridoma -these are purified and rapidly divide in culture to monoclonal antibodies

Answer 79

- seperating chemicals via agglugination - drugs can be directly transported

Answer 80

- harmful to animals but dont cost - help to rduce suffering and save lives - cheap and dont have to pay animals

Answer 81

- antigen added - sample added - antibody attached - enzyme linked antigen added - well washed - substeate added = colour change

Answer 82

- Antibody into well - sample added - antigen attached - enzyme linked antibody attached - well washed -substrate added = colour change