EXCHANGE MAYRUAN

Question 1

AMOEBA

Answer 1

unicellular
small
large sa to vol
simple difusión
short pathway
quick diffusion
don’t need specialised exchange surfaces

Question 2

flatworms

Answer 2

changes body shape to allow organisms to inc sa to vol
improve exchange of materials
long and thin
can have same volume as another rounder organism but larger sa to vol ratio

Question 3

insects

Answer 3

tracheal system
spiracles present along thoracic and abdominal segments
lead to tubes called tracheae which branch into smaller tubes tracheoles
carbon dioxide can diffuse from the cells into the tracheoles and oxygen diffuses from the tracheoles into the body cells
these respiratory gases are exchanged with env via spiracles

Question 4

bony fish

Answer 4

-each gill has 4 gill arches which have several gill filament which have lamellae inc sa
-they also have blood capillaries carrying deoxygenated blood to the surface of the secondary lamella where exchange takes place

Question 5

ventilation in bony fish

Answer 5

buccal cavity
change vol
movements of operculum coordinated with movements of buccal cavity
water pushed from cavity operculum moves outwards

Answer 6

by contracting and relaxing quickly lots f energy fir particles which increase the rate of diffusion
high surface area to volume ratio

Question 7

gas exchange in insects

Answer 7

run from the body surfaces into tissues
transport gases directly between the external environment and the body cells
each segment of the insect has a pair of lip like orpeniingd called spiracles

Question 8

countercurrent flow

Answer 8

means a steep exchange gradient is maintained so oxygen continues to diffuse from the water to the blood across the whole of the exchange surface
-same in humans kidney loop of henley

Question 9

fish gills

Answer 9

showing rows of lammalle
water flows across the lamella in the opposite direction to blood flow to maximise gas exchange

Question 10

palisade

Answer 10

tall
lots of chloroplast
any light that transmit through can be absorbed by other chloroplasts

Question 11

plants

Answer 11

-need to exchange gases with the environment for respiration and photosyhtnetsis
their leaves are adapted to increase the efficiency of the process
the leaves of dicotyledonous plants are flat, thin and wide
there are many small pores on the underside of the leaf called stomata
oxygen and co2 are able to diffuse through the stomata and into the mesophyll pf the leaf
air spaces allow the gases to move freely inside the leaf and into the plants cells

Question 12

insects

Answer 12

insects are alble to open and close their spiracles and so have some control over water loss
if conditions are particularly dry or the insects is inactive the spiracles will remain closed or partially open
if the conditions are relatively moist or the insect is active the spiracles remain open

Question 13

opening and closing of stomata

Answer 13

controlled by guard cells
when water enters the guard cells they become turgid and the stomata open
when water leaves becomes flaccid and close
log co2 and water supply affect opening and closing

Question 14

adaptions

Answer 14

thick waxy cutivle
fewer stomata
sunken stomata
fine hairs on leaf surface
rolled leaves
shallow extensive root system

Question 15

captions effect on water conservation

Answer 15

less water loss via cuticle
fewer pores for water loss
traps moist air -reuces conc gradient
reduces surface area
condensation formed at night absorbed

Question 16

lungs

Answer 16

-the human gas exchange system comprises the main windpipe ,trachea which splits into two bronchi
each branches has multiple branches called bronchioles which terminates in alveloli the site of gaseous exchange

Question 17

cartilage

Answer 17

the trachea and bronchi are held open by bands or cartilage to prevent them from collapsing and ensure constant air flow bronchioles nearer the branch also have bands of cartilage but these are lost as they become narrower

Question 18

wall of alveolus

Answer 18

made up of singular layer pf squamous epithelium
these epithelial cells are very thin
freely permeable to repository gases
the walls of the blood capillaries surrounding the alveoli are also one cell thick so the barrier between blood and air

Question 19

all psrticles in a liquid move in one direction fue to a difference in pressure high to low

Question 20

blockage of coronary artery

Answer 20

lack of o2 and good supply to cells
anaerobic respiration ,lactic acid proteins denature ,angina and cardiac ischeemia ,mi

Question 21

coronary arteires

Answer 21

branch off the aorta and supply the muscular walls with oxygenated blood and glucose
this allows the cels of the cardiac muscle to respire and contract rhythmically over 4000 times every hour
the heart has a left and right coronary artery supplying each side of the entire heart
if a coronary artery gets blocked part of the heart is starved of oxygen and this can lead to a heart attack.

Question 22

systole

Answer 22

heart contracts
pressure increases

Question 23

diastole

Answer 23

pressure decreases
heart dilates

Answer 24

1)generate electrical signals
2)self stimulating
3)myogenic
wave of depolarisation through atria muscle contraction -atrial systole
insulation prevents electrical signal from moving into ventricles
avn - receives electrical signals from atria directs it down septum
via specialised neurons called purikne fibres
bundle of this insulated to prevent signal leave

Question 25

pulse flow

Answer 25

when muscles strech and recoil

Question 26

collagen in arteries

Answer 26

acts as a connective tissue

Question 27

adaption of xylem

Answer 27

continuous tube of dead cells
no end walls
water pass easily through the plants
rings of lignin for extra support prevent from collasping

Question 28

phloem structure

Answer 28

thin layer of cytoplasm in sieve tube elemts

dense cytoplasm of companion cell

plasmodesmata linking cytoplasm of companion cell and sieve tube elements

Question 29

assimilates

Answer 29

substamces made by the plant

Question 30

trasnolaction

Answer 30

movement of nutirents around a plant

minerals dissolved in water
sugars
amino acids
bi directional
active process
requires energy

Question 31

sources

Answer 31

provide assimilates to the plnat from reaction or storage for transport

Question 32

examples of sources

Answer 32

green leaves and stems
stroage organs eg. tubers and root tabs- veins found in aqautic plants
food stores in seeds

Question 33

sink

Answer 33

these use assmilates from the plant in various processes
growing roots
active processes in the roots and stem
meristem cells actively dividng
developing stores eg. seeds ,fruits or stroage