B6 - plant structure and function

Question 1

what is the word equation for photosythesis

Answer 1

CO2 + water —-> glucose + oxygen

—-> = light and chlorophyll

Question 2

how do plants produce biomass

Answer 2

use energy from the sun to produce glucose, some of which is used to make biomass

Question 3

what is biomass

Answer 3

the mass of a living material

Question 4

where does photosynthesis occur

Answer 4

in chloroplasts
contain chlorophyll which absorbs light

Question 5

what sort of reaction is photosynthesis

Answer 5

endothermic

Question 6

what is an endothermic reaction

Answer 6

energy is absorbed
products have more energy than reactants

Question 7

what controls opening and closing of the stomata and how

Answer 7

guard cells: by changing shape
- when swollen with water (turgid) stomata opens
- when limp+low on water(flaccid) stomata closes

Question 8

what is the role of waxy cuticle layer on leaves

Answer 8

allows plants to retain water
preventing too much loss

Question 9

what is the role of broad flat leaves

Answer 9

large surface area, sunlight can directly enter the leaf, and more is absorbed

Question 10

what is the role of veins on leaves

Answer 10

transport water and nutrients through the plant

Question 11

why are leaves adapted to be thin

Answer 11

allows efficient diffusion of co2 and o2 in and out of the plant

Question 12

what is meant by rate of reaction (of photosynthesis)

Answer 12

how fast or slow photosynthesis occurs

Question 13

what is a limiting factor

Answer 13

factors that can limit photosynthesis if there isnt enough of it

Question 14

what are the limiting factors of photosynthesis

Answer 14

• CO2 conc
• light intensity
• temperature

Question 15

explain the graph for light intensity on rate of photosynthesis

Answer 15

• rate - Y, light intensity - X
• directly proportional to rate (increase together)
• levels off as there is another limiting factor, increasing light intensity no longer has an effect

Question 16

explain the graph for CO2 conc on rate of photosynthesis

Answer 16

• rate - Y, CO2 conc - X
• directly proportional to rate (increase together)
• levels off as there is another limiting factor, increasing conc no longer has an effect

Question 17

explain the graph for temperature on rate of photosynthesis

Answer 17

• rate - Y, temp - X
• directly proportional, both increase
• reaches and optimum temperature
• any hotter rate decreases as enzymes denature

Question 18

why is rate of photosynthesis inversley proportional to distance from a light source

Answer 18

• light intensity decreases the further away from a light source an object is
• lower light intensity means a slower rate of reaction
• greater distance = lower rate

Question 19

how does water move through the walls of a plant/ enter a root hair cell

Answer 19

osmosis - high to low conc

Question 20

how does O2 enter root hair cell

Answer 20

diffusion - O2 conc typically greater outside plant than inside

Question 21

how do minerals enter a root hair cell

Answer 21

active transport - as conc of minerals is usually greater in the root hair cell than outside. (against conc gradient)

Question 22

what is a concentration gradient

Answer 22

the difference in concentration of something in different areas

Question 23

why is active transport used to transport mineral ions into root hair cell

Answer 23

minerals always need to be absorbed into a plant no matter where the higher conc is

Question 24

how are root hair cells adapted to taking in water and mineral ions

Answer 24

• many mitochondria: energy for active transport
• thin cell wall: faster osmosis + diffusion
• large SA: take in optimum water and minerals
• long hair extentions to cell membrane

Question 25

how does increased airflow (wind) effect rate of transpiration

Answer 25

rate increases as concentration gradient is maintained as the airflow carries water vapour away from the outside of the plant

Question 26

what are stomata

Answer 26

tiny pores on the surface of a plant allowing CO2 + O2 to diffuse directly in and out of the leaf

Question 27

what is the function of palisade cells

Answer 27

packed w chloroplasts and close to the surface of the leaf allowing light to reach them efficiently

Question 28

what is transpiration, and how does it occur

Answer 28

the evaporation and diffusion of water from a plants surface happens due to a constant transpiration stream down a plant

Question 29

how does high humidity effect transpiration

Answer 29

decreases rate as the conc of water is higher outside the leaf than inside and diffusion cant occur

Question 30

how does increased temp effect transpiration

Answer 30

increase rate as there is an increase of water evapourating from the stomata

Question 31

how to measure the rate of transpiration

Answer 31

total distance/ time taken

Question 32

what is translocation

Answer 32

the movement of food eg. sucrose up AND down a plant uses energy from respiration

Question 33

what is job of phloem

Answer 33

transport food to rest of plant for immediate use or storage

Question 34

what is xylem

Answer 34

hollow tube cells that transport water up the plant

Question 35

How is phloem adapted for its function?

Answer 35

- Made up of elongated living cells. - Cells have sieve tubes that connect them together, have tiny pores so that sucrose can move through into other cells. - Sieve tube cells have few organelles to allow the efficient transport of substances.

Question 36

How is xylem adapted to its function?

Answer 36

Hollow tubes made of dead cells strengthened by lignin to maintain structure and allow water and minerals to pass through

Question 37

what direction does phloem transport

Answer 37

up and down

Question 38

what direction does xylem transport

Answer 38

up

Question 39

what is a transpiration stream

Answer 39

the flow of water through a plant, from the roots to the leaves, via the xylem vessels.