B2 - scaling up (from PMT)

Question 1

describe mitosis (including the cell cycle)

Answer 1

-the chromosomes are replicated
-the chromosomes line up in the middle
-the chromosomes are pulled apart
-membranes form around the chromosomes and the cytoplasm divides
-the two cells then continue growing

Question 2

define cell differentiation

Answer 2

differentiation is where cells become specialised for a particular function

Question 3

how are sperm cells specialised to their function?

Answer 3

-large tail for movement
-acrosome (containing enzymes) to digest the egg membrane
-lots of mitochondria for energy
-haploid nucleus

Question 4

how are nerve cells specialised to carry impulses?

Answer 4

-they have a long axon to transport the impulse long distances
-contain extensions to connect to other nerve cells and contain neurotransmitters to transmit the impulse

Question 5

how are root hair cells specialised to take up water and minerals?

Answer 5

-they have lots of mitochondria to generate energy
-they have a large surface are for faster diffusion

Question 6

what are stem cells?

Answer 6

stem cells are undifferentiated cells and can develop into lots of different types of cells

Question 7

where are animal stem cells found?

Answer 7

animal stem cells are found in embryos and in the bone marrow

Question 8

what are stem cells used for?

Answer 8

stem cells are naturally used for growth and repair. they can also be used in treatments for parkinson’s disease and burns.

Question 9

give 4 examples of substances transported within organisms

Answer 9

-oxygen is transported in for respiration
-carbon dioxide is transported out from respiration
-dissolved food molecules from digestion
-urea and waste products

Question 10

why do mammals need a double circulatory system?

Answer 10

double circulatory systems have blood at a higher pressure, allowing it to flow faster and move substances quickly around the body

Question 11

what is the difference in function between veins, arteries and capillaries?

Answer 11

-arteries carry blood away from the heart
-veins carry blood towards the heart
-capillaries flow close to tissues for exchange

Question 12

describe the structure of the lungs

Answer 12

-the trachea branches into two bronchi
-the bronchi branch into bronchioles
-these bronchioles end in alveoli which are lined with capillaries for exchange

Question 13

what is the name of the wall that separates the right and left sides of the heart?

Answer 13

the septum

Question 14

what is the name of the artery that supplies the heart tissue with blood?

Answer 14

the coronary artery

Question 15

what type of muscle is the heart made of?

Answer 15

cardiac muscle

Question 16

why is the wall of the left ventricle thicker than the wall of the right ventricle?

Answer 16

the left ventricle has to pump blood a further distance around the whole body so the blood needs to be under a higher pressure

Question 17

how is plasma adapted as a transport medium?

Answer 17

plasma is the liquid part of the blood and most molecules transported in blood need to be dissolved in water

Question 18

how are root hair cells adapted to their function?

Answer 18

-long root hair extension to increase surface area for uptake
-thin membranes to decrease the diffusion distance

Question 19

what does the xylem transport?

Answer 19

water and minerals

Question 20

state 3 benefits of transpiration

Answer 20

-the stream of water cools the plant
-the water helps to support the plant by creating turgor pressure
-the plant has a constant water supply for photosynthesis

Question 21

how is the xylem adapted to transport water?

Answer 21

-it is waterproofed using a substance called lignin
-the xylem cells are dead and have no organelles so there is more space for water

Question 22

describe the structure of leaf tissue

Answer 22

-waxy cuticle
-upper epidermis
-palisade mesophyll
-spongy mesophyll
-lower epidermis (guard cells in the middle)

Question 23

describe the process of transpiration

Answer 23

-water is lost through the stomata
-more water is drawn up to replace the lost water

Question 24

define the transpiration stream

Answer 24

the flow of water through a plant

Question 25

how does light intensity affect the rate of transpiration?

Answer 25

-the brighter the light, more stomata are open

Question 26

describe how to use a potometer to measure transpiration

Answer 26

-the plant is placed in the end of an airtight tube containing water
-a single air bubble is introduced to the tube and the movement of the bubble is measured over time

Question 27

what does the phloem transport?

Answer 27

sugars like sucrose

Question 28

describe translocation

Answer 28

the movement of sugars up or down the phloem from source to sink (with the use of energy)