C6 Cells Flashcards

Question

CELL MEMBRANE STRUCTURE - fluid mosaic model (how? functions?) Components: - phospholipids (structure, arrangement, properties) - cholesterol (properties) - proteins (2 types, functions)

Answer 1

FLUID MOSAIC - fluid: phosphates are able to move freely - mosaic: membrane is embedded with proteins and other elements PHOSPHOLIPIDS - hydrophilic head, hydrophobic tail - arrange into a bilayer: tails align face inwards, heads align face into cell and out of cell - restricts passage of many substances - flexible: allows breaking/reforming of membrane for substance entry/exit CHOLESTROL - in animal cells - moderates membrane properties - immobilises membrane surface, reducing fluidity - prevents crystallisation - prevents small H2O molecules from permeating membrane PROTEINS - 2 Types: Integral (permanent, transmembrane (through)), peripheral (temporary, on surface) - Functions: JETRAT Junctions (connect cells) Enzymes (provide AS for substrates) Transport (of substances in/out of cell) Recognition (between other cells) Anchorage (for other substances) Transduction (reception for hormones)

Answer 2

- Semi-permeable: allow some substances in but not others - Affected by: temp + pH (cause denaturing), ethanol

Answer 3

PASSIVE - no ATP used, just KE - high to low conc ('with the flow') - with the conc gradient ACTIVE - ATP used - low to high conc ('against the flow') - against the conc gradient

Answer 4

Passive: Molecules move from a high to low conc. SIMPLE DIFFUSION - small, non-polar molecules - the higher the conc gradient, the faster the rate of diffusion - occurs across semi-permeable membrane FACILITATED DIFFUSION - larger, polar molecules - the higher the conc gradient, the faster the rate of diffusion - occurs through channel (integral) proteins OSMOSIS - net movement of free water molecules - from a region of low conc of solute to high conc of solute - occurs across semi-permeable membrane Why? - water is a universal solvent, and will bond with the solutes - this means that in a solution with a high conc of solutes, there will be less free water molecules - the free water molecules will move to equalise the solutions - results in equal number of free water molecules either side, but more volume on the side with a higher solute conc

Answer 5

the difference in concentrations between two areas (e.g. inside a cell and out)

Answer 6

polar/charged molecules that are dissolved in water

Answer 7

Osmolarity is the measure of a solute conc in a solution that a cell is in. HYPOTONIC - low solute conc outside of cell, high conc inside - free H2O moves into cell - solution loses H2O HYPERTONIC - low solute conc inside of cell, high conc outside - free H2O moves into solution - cell loses H2O ISOTONIC - conc of solute is balanced both inside cell and in the solution - no net H2O flow

Answer 8

ANIMAL - Hyper (solution has high conc): water leaves cell cytoplasm shrinks, cell shrivels - Hypo (solution has low conc): water enters cell, cytoplasm expands, cell swells (possibly lysis occurs = burst) PLANT - effects of uncontrolled osmosis are the same as animal cells, except cells are not as affected as much - cell wall keeps shape, prevents lysis or complete shrivelling

Answer 9

MEMBRANE PUMPS - pumps are carrier proteins that facilitate active transport - move mols from low to high conc - e.g. sodium potassium pump BULK TRANSPORT - large materials move in/out of cell enclosed in vesicles - vesicles fuse with the cell membrane to allow entry/exit of the materials - cell size is maintained via endocytosis (removes phos lipids) and exocytosis (adds phos lipids back) Endocytosis - substances move into cell - cell membrane folds around substance, creating a vesicle that moves into the cell - e.g. proteins, carbs - liquids enclosed: pinocytosis (drinking) - materials enclosed: phagocytosis (eating) Exocytosis - substances move out of cell - vesicle joins with membrane, substances pushed out other side - e.g. waste, proteins

Answer 10

a 'bubble' of fluid and important materials, enclosed by a membrane - used in active

Answer 11

- DNA molecules - 23 pairs in humans (X shape) - 46 single (half an X) - represented by n (2n = diploid, n = haploid)

Answer 12

- do not assume that n = 23, 2n = 46 - this is only in humans - use n/2n unless specified otherwise

Answer 13

- a visual representation of an entire organism's chromosomes - in humans there should be 22 pair of somatic chromosomes, 1 pair of sex chromosomes - may indicate genetic disorders/mutations (e.g. extra chromosomes)

Answer 14

- the stages of cell division, a cycle Prophase: chromosomes condense to form X shape Metaphase: they line up in middle of cell Anaphase: sister chromatids are pulled apart to either end of cell Telophase: two nuclei form Cytokinesis: cell splits, two new cells are formed Interphase: normal cell state

Answer 15

FUNCTIONS - make new somatic cells - used for growth, repair, replace old cells - for asexual reproduction in some organisms - genetic material is conserved PROCESS - 1x PMAT - 2n-(dna rep)-4n-2n (2x daughter cells) - daughter cells are genetically identical to parent cells: have same set of DNA, any variation is due to random mutation

Answer 16

FUNCTIONS - to make genetically unique gametes - required for sexual reproduction Genetic material is reduced - gametes are haploid (n) - undergo DNA rep - parent cell divides 2x to produce 4 daughter cells, each haploid (n) - during the process, genetic variation occurs PROCESS - 2x PMAT: Meiosis I (genetic variation occurs), Meiosis II (normal PMAT) - 2n-(dna rep)-4n-(meiosis I)-2n-(meiosis II)-n (4x daughter cells) - daughter cells are genetically unique to parent cells: due to genetic variation in Meiosis I

Answer 17

- both occur during Meiosis I (1st PMAT) - both cause genetic recombination (diversity between daughter cells) CROSSING OVER - occurs in Prophase I - 'segments' of chromosomes (individual genes) swap between other chromosomes INDEPENDENT ASSORTMENT - occurs in Metaphase I - chromosomes are separated at random to either side of the cell before division

Answer 18

- active transport, against conc gradient (high to low conc) WHY - in animal cells, K is needed in the cell, Na is needed out of cell - however there is a higher conc of K inside cell, higher conc of Na out of cell - active transport must be used to force transport against the conc gradient PROCESS - inside cell, Na binds to pump - phosphate from ATP binds to pump, forces pump to open to outside of cell - Na is released, K enters - phosphate is released, pump opens back to inside - K released, cycle continues

Answer 19

FUNCTION - produced by males to fertilise an ovum - contain 1/2 genetic material required to form embryo STRUCTURE - streamlined shape: allows easy entry into ovum - acrosomes: located on head, contain enzymes that identify the ovum, and break down ovum membrane - flagella: allows movement - midpiece: contains many mitochondria that allow the cell to move

Answer 20

FUNCTION - produced by females and released from ovaries - contains 1/2 genetic material required to form embryo STRUCTURE - outer layer: follicle cells provide padding and protection, prevents multiple sperm from entering - 2nd outer layer: sperm recognise it and bind to fertilise - cell plasma/yolk: provides nutrition to developing egg

Answer 21

FUNCTION - produce myelin, an insulating sheath on nerve fibres STRUCTURE - spokes provide myelin: can have up to 50 protruding from main cell body, providing myelin to up to 50 nerve fibres at once

Answer 22

FUNCTION - are the muscle cells in the tissue that is connected to the skeleton - vital for body movement STRUCTURE - long cells: control movement of long bones - myofilaments: create muscle contractions through sliding action - many mitochondria: allow lots of ATP for movement - multiple nuclei: enhance O2 uptake and tissue repair

Answer 23

FUNCTION - vital for bone synthesis + mineralisation - synthesises molecules STRUCTURE - create a matrix: forms new layers of bone - limited organelles: make cells robust and strong

Answer 24

FUNCTION - able to transform into many specialised cells via dividing - some stem cells are able to transform into many different types, some only limited types STRUCTURE - standard animal cell before it divides - division: can divide asymmetrically (to produce a different cell) or symmetrically (to produce stem cells)

Answer 25

FUNCTION - located in eye's retina - converts light to signals that the brain reads to produce an image STRUCTURE - two specialised types: cones (colour) and rods (b/w) - photopigment: contains large amounts at a high density, allowing the majority of light photons to be absorbed

Answer 26

FUNCTION - located on the outside layer of root - extract water and nutrients from the soil STRUCTURE - large SA:V ratio: long, skinny, tubular and horizontal shape allows efficient absorption - thin cell walls: allow efficient transport into cell

Answer 27

FUNCTION - main photosynthetic cell STRUCTURE - rectangular shape: cells fit together to maximise the number of cells in the leaf - found in upper side of leaf: allow max light energy to penetrate the cell - many chloroplasts: allow for a high Phs rate - rigid: strong cell walls + inflexible for plant strength

Answer 28

FUNCTION - make up cardiac muscle in the heart - responsible for contracting/relaxing to keep blood pumping STRUCTURE - elongated cells: interconnected through disks, branched for faster contraction - striated: alternating filaments pull towards each other to perform contractions - many mitochondria: cells perform efficient aerobic resp, are resistant to fatigue, allowing continuous contractions

Answer 29

FUNCTION - located in the nervous system - responsible for allowing an organism to move by sending signals from the brain to the muscles STRUCTURE - dendrites: extend away from the cell to receive messages, increasing SA - myelin sheath: fatty material over axons form a sheath, providing insulation, speeding up transmission of electrical impulses

C6 Cells Flashcards

(53 cards)