Unit 1 Topic 2: Multicellular Organisms

Question 1

Properties of stem cells

Answer 1

1. unspecialised
2. potency
3. self-renewal for long periods of time

Question 2

Potencies

Answer 2

totipotent - can form any cell even the embyronic cells (placenta)

pluripotent - can for any type of body cell

multipotent - forms specialised body cell

Question 3

hierarchy of organism

Answer 3

1. cells
2. tissues
3. organs
4. organ systems
5. organisms

Question 4

differentiation

Answer 4

cell specialisation is determined by gene expression

disadvantages - cells are incapable of independent survival

advantages - increased efficiency due to specificity

Question 5

structural features of an efficient gas exchange surface

Answer 5

thin
moist
high SA:V
extensive capillary system

Question 6

capillaries

Answer 6

thin - rapid diffusion
small diameter - slows flow of blood to maximise exchange
high SA:V - more efficient gas exchange
blood flow regulation - tissues recieve appropriate supply of nutrients to meet metabolic requirements.

Question 7

direction of blood travel

Answer 7

from artery (from heart) to vein (to heart) gets more oxygenated, co2 goes to alveoli.

Question 8

mechanical digestion

Answer 8

chewing - increases SA:V
peristalis moves food to stomach where stomach muscles churn it

Question 9

Chemical digestion

Answer 9

mouth (ph 7 ) - amylase, break down starches into sugars

stomach (ph 1) - pepsin and protease, breaks down proteins into amino acids

small intestine (ph 8) - lipase, breaks down lipids into fatty acids and glycerol

Question 10

Absorption

Answer 10

vili increase the SA, increases efficiency
fat soluble goes through lacteals
water soluble goes through the epithelial wall
large intestine primarily for water reabsorption and waste removal

Question 11

the nephron

Answer 11

glomerulus - filters out the blood and dumps water and nutrients into the bowman’s capsule, done through high pressure, which forces out the water and nutrients

bowman’s capsule - collects filtrate from blood

proximal convoluted tubule - reabsorb water and nutrients actively

loop of henle - reabsorb water while pumping out salts

distal convoluted tubule - actively reabsorbs salts and water

collecting duct - collects waste, antidiuretic hormone hormone makes it more permeable

Question 12

ammonia

Answer 12

dilute
toxic
low energy

Question 13

urea

Answer 13

concentrated
not that toxic
some energy

Question 14

uric acid

Answer 14

super concentrated
not toxic
lots of energy

Question 15

stomata and guard cells

Answer 15

gas exchange and transpiration
vacuoles control open or closed

Question 16

leaf structure

Answer 16

waxy cuticle - stops transpiration
epidermis - transparents allows for light
palisade mesophyll - main site for photosynthesis
spongy meso - allows for efficient gas exchange
xylem - water for photosynthesis
phloem - nutrients for photosynthesis

Question 17

how does leaft facilitate gas exchange

Answer 17

1. waxy cuticle
2. spongy mesophyll
3. surface area, more stomata, more stomata

Question 18

Xylem

Answer 18

dead cells, vessel elements and tracheids, unidirectional, transport of water

Question 19

phloem

Answer 19

companion cells, sieve tubes, sive plates, transport of nutrients, multi-directional

Question 20

Xylem transport

Answer 20

root pressure, minerals are actively transported into the xylem causing high concentration of solutes causing an influx of water due to osmosis.

the transpiration stream is the continous movement of water up the column, which stays together through the cohesion of water molecules to maintain the column

Question 21

Phloem translocation

Answer 21

sugars loaded into the phloems actively, high water pressure drives sap to directions to be unloaded and then the osmotic pressure reduces and returms to the xylem.

Question 22

factors that affect transpiration

Answer 22

wind, humidity, temperature, light, SA, number of leaves