A level Biology Recap Flashcards by s sriv

why is (potassium) cyanide toxic? (2)

inhibit aerobic respiration (1) inhibit catalase

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catalase function

hydrolyses hydrogen peroxide to form water and o2

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some enzymes must have some of their amino acids removed before it can catalyse reactions. what is the name of this ‘form’ of an enzyme?

inactive precursor form

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some enzymes must have some of their amino acids removed before it can catalyse reactions. name exampels and say why this is important

digestive enzymes have blocked active sites to prevent it digesting the cell’s molecules

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some enzymes must have some of their amino acids removed before it can catalyse reactions. why can’t enzymes catalyse when these extra amino acids are present

blocks active site, once removed actiev site can assume correct shape & are exposed

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fill in the gap: … increase efficiency of metabolic reactions without increasing substrate concentration.

multi-enzume complexes

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name 2 methods of improving enzyme metaboloic reactoons efficeincy

using mult-enzyme compleses
keep enzymes & substrates in same vicinity to reduce diffusion time
metabolic reactions are separated in cell, placed in optimum conditions

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how are metabolic reactions controlled (4)

product of 1 enzyme- catalysed reaction becomes substrate for next enzyme-catalysed reaction (1),
process repeats (2
)until last product becomes non-competitive inhibitor for first enzyme (3).
when end product concentration decreases, then it detaches from first enzyme to allow metabolic path to run again ( 4)

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what is health

free from, disease / illness ;

physical and mental and social wellbeing / AW

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how parasites can benefit form hosts

warmth, protection, feeds on hostallows transmission to new host

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food spoilage by bacteria causes ….

…(causes) change in, appearance / smell / texture / taste

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food preservation examples

freeze food, cook food, salt/sugar the food

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where are T cells produced

thymus

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where are B cell produced

bone marrow

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what does humoral resposne occur

when toxin or pathogen is detected in the blood

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what type of respose use B cells

humoural

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what type of respose use T cells

cell mediated

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reasons for using embroyonic stem cells

(incurable) diseases cured (1); improved

quality of life

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reasons against using embroyonic stem cells (2)

embroyo has rights, religiois objections

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what is cartilage made out of?

elastin and collagen fibres

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fill in gaps: cartilage is a firm … tissue, composed of … embedded in …
(3)

connective tissue, chondrocyte cells, extracellular matrix

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what is skeletal muscle made out of?what does this contain?

myofibrils contains contractile proteins

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Differences between diffusion & mass flow?

Diffusion is random motion of particles – particles move down their concentration gradient and
different particles may move in different directions.
In mass flow all particles move together

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give example of mass flow

plasma leaking to tissues to form tissue fluid, transpiration stream

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advantages of mass flow

Mass flow is faster and can move large amounts of fluid long distances, quickly.

what is central 'line' on leaf called

central midrib

name for packing tissues in plants

parenchyma

name for area in roots, stems which is an area of packing tissue

medulla

endodermis defintiion

what is the word describing this defintion? a layer of cells surrounding the vascular tissue in the root of the plant, helping in water movement in the casparian strip

collenchyma defintion (3)

cells with thick celluslose walls (1) to strengthen vascular bundles & outer parts of stem (2) whilst allowing some flexinility(3)

wht does collenchyma strengthen

vascular bundles & outer parts of stem

sclerenchyma definition

plant cells that have lignifies walls and are used to strengtehn stesm and leafmidribs; solid & non-living .

where are sclerenchyma found

stems and leaf midribs

why are roots subjected to pulling forces

root is pulled as wind is pushing stem over

3 types of ways liginin is laid on xylem vessels

spirals, annular, reticulate

which vacular vessel contains bordered pits

xylem between adjacent xylem vessels

what (key word) is trasnported in phloem

assimilates

difference between parenchyma and companion cell

specialized parenchyma cell called a companion cell is for phloem

whjat is the point of sieve tubes (2)

to block spread of pathogen during infection by callose at sieve tubes gives structural support to keep it open against pressue

which vascular bundle contains nucleas or cytoplasm

neither

which vascular vessel uses plasmodesmata

phloem only

plasmodesmata defnition

Plasmodesmata are small channels that directly connect the cytoplasm of neighboring plant cells to each other, establishing living bridges between cells.

cytokinesis in animal cells

Animal cells cleavage furrow forms around middle of cell (1); furrow pulls inwards and fuses

homologous chromosomes defnition

pair of same chromosomes, one from each parent (1); which have the same genes but can have different alleles of each gene

what are crossed over chromosomes called

recombinant chromosomes

give 2 functions of xylem tissue

transports water & minerals in transpiration | supports the plant

where is endodermis present in plant

roots only

function of the constant region of antibodies

binds to phagocytes

why are more than 1 measurements taken in a PAG

to take out a mean, and get rid of anomalies = more reliable results

why is there an increase in rate of transpiration caused by brighter light

Brighter light causes the stomata to open wider, so more water vapour can diffuse out of the stomata.

turgid defnition

WHen a cell or tissue that is full of water and is therefore firm.

flaccid defnition

Flaccid means that the cell or tissue is not full of water and is therefore soft.

water potential defintion

Water potential is a measure of the tendency of water molecules to move from one place to another.

osmosis defintion

Osmosis is the movement of water molecules from a region of less negative (high) water potential to a region of more negative (lower) water potential through a partially permeable membrane.

plasmolysis

Plasmolysis is seen where the plasma membrane pulls away from the cell wall, due to loss of water from the cell by osmosis.

explain how a cell becomes plasmolysised

As water leaves the cell by osmosis, the cytoplasm and vacuole shrink. This pulls the plasma membrane away from the cell wall.

true or false sive tube elements have nuclei

false

explain difference between diffusion & mass flow

Diffusion is the random motion of particles moving down their concentration gradient. In mass flow all particles move together

what causes opening and closing of valves in the heart

pressure changes between chambers

how is blood pressure maintained in aorta

elastic tissue

what happens if damaged DNA is found at checkpoint G2 (2)

the cell cycle is halted (1) and the cell tries to | repair the damage. (2)

label a leaf's midrib crossection

search it up

suggest why fish can't survive long out of water

In air gill filaments all stick together (1); SA for gas exchange is greatly reduced and so fish dies from lack of oxygen (1)

order of muscle and fibres in blood vessels

lumen --> endothelium ---> elastin fibres --> smooth muscle---> collagen fibres

middle layer of artery wall

tunica media

inner layer of artery wall

tunica intima

outer layer of artey wall

tunica adventitia

true or false veins and capillaties dont have elastin fibres in walls

false, veins don't capillaires only have endodermis

order of muscle and fibres in capillaries

lumen and endothelium

artery to capillary blood vessel called

arterioles

capillary to veins blood vessel called

venules

advantages of closed circulatory system (3)

higher pressure = more blood flows rapid transport of O2 and waste transport is independent of body moevemnt

how do tissues in artery walls reduce the fluctuations in blood pressure(3)

Wall of artery stretches, (1); the collagen in the wall prevents over stretching(2); the elastic tissue recoils to return the wall to original size (3) to maintain pressure

how is tissue fluid formed

formed by plasma leaking from capillaries

oncotic pressure of blood

-3.3kPa

aerterial end of capulary pressure of blood

4.6kPa

venous end of capillary presure of blood

2.3kPa

which direction does hydrostatic pressure move in capillaries

down concentration gradient either out or into capillaries

blood function (2)

tranport medium | buffer to minimise pH changes

where does excess tissue fluid go

into lymphatic system

what does the lymphatic system do to prevent drop in blood pressure in the circulatory system

lymph is eventually returned to blood in subclavian vein

what is tissue fluid called in lymphatc system

lymph

what is in lymph

same as tissue fluid but with more co2 & less glucose & o2

what are 3 parts of G0 phase of cell cycle

apoptosis, senescense, differentiation

what is senescence

irreversible growth arrest, when cell ages & permanently stops dividing but doesn't die

true or false if error in dna, cell cycle will go back to previous checkpoint

false, cells cycle progressses in 1 direction

A level Biology Recap Flashcards

(86 cards)