Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Wjec Biology Unit 2 > 2.3 Plants > Flashcards

2.3 Plants Flashcards

1
Q

What are the three levels of transport in plants

A

Cellular uptake
Tissue transport
Whole plant transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are water and ions mainly absorbed

A

Through root hair cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Function of epidermis in roots

A

Root hair - uptake of water and mineral ions

Protect roots as they grow through soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cortex parenchyma function

A

Acts as storage organ

Intercellular spaces allow movement of water and ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Endodermis function

A

Has waterproof layer to force water and ions into the cytoplasm of the endodermal cells
Controls transport in the xylem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pericycle function

A

Role in controlling transport into xylem

Site of lateral root growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Xylem function

A

Transports water and ions from the roots to the stem and leaves.
Provides support for the plant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phloem function

A

Transports the products of photosynthesis to the roots from the leaves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cambium function

A

Meristematic tissue that can undergo mitosis to produce more xylem and phloem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Look

A

Root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Look

A

Root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Look

A

Root hair cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Function of cuticle

A

Reduces water loss from evaporation

Transparent to allow light to pass through photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Function of epidermis in stem

A

Protection of stem

May have hairs to deter insects/animals from eating them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Collenchyma function in stem

A

Cell walls thickened with cellulose to strengthen the stem while remaining flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cortex parenchyma function in stem

A

Can act as a storage organ

Intercellular spaces allow movement of water and ions and gases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pith parenchyma function in stem

A

Thin-walled cells that act as packing tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Sclerenchyma function in stem

A

Lignified cells that provide strength and support to the stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Look

A

Stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Look

A

Stem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What cell types found in xylem?

A

Xylem vessels
Tracheids
Xylem parenchyma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Xylem vessels function

A

Transport water and minerals from the roots to other parts of a plant
End walls of these break down to form long tubes that extend from roots to stem and leaves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Tracheids function in xylem

A

Provide strength to tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Xylem parenchyma function

A

Thin walled, living cells

Act as packing tissue between xylem vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What kind of tissue
Xylem
26
Which cell types of xylem are dead?
Tracheids and xylem vessels
27
What are the walls of tracheids and xylem vessels made up of?
Lignin | Impermeable to water
28
Phloem sieve tubes
Contain little cytoplasm Few or no organelles Cell walls made of cellulose
29
Companion cells
Accompany sieve tubes Provide support to sieve tubes Involved in transport of substances in and out of sieve tubes Have many mitochondria- active transport
30
How are companion cells and sieve tubes connected
Plasmodemata
31
Look
Phloem
32
What are sieve tubes and their function
End walls of phloem sieve tubes are perforated by small pores Strands of cytoplasm pass through the pores from one phloem sieve tubes to next
33
Look
Phloem
34
What does the vascular bundle contain
Xylem Phloem Cambium Other cells
35
What can root pressure do
Push water up the xylem against gravity
36
What is guttation
When water that reaches the leaves us forced out which causes a beading of water upon the leaf tips
37
What is root pressure caused by
* active transport of ions into stele - lowers water potential * water passively flows into roots - pushing water up * gravity acts against it so that very little is formed in tall plants as weight of water pushes down on contents
38
What is the transpiration stream
A constant stream of water molecules is formed between roots and leaves
39
Explain the transpiration stream
* stomata opens to let CO2 in * water vapour leaves air spaces via stomata * water potential is lowered in leaves so a water potential gradient between roots, leaves and outside air * water lost by leaves replaced by evaporation of thin layer of water that clings to mesophyll cells * as water evaporates it is replaced by water clinging to inside of air spaces * a tension on the water in xylem which pulls water to direction of water loss
40
How does cohesion and adhesion affect transpiration stream
Cohesion - water is strong enough to transmit the pulling force down to roots Adhesion - of water to lignin cells of xylem aids in resisting gravity
41
What is transpiration?
Process by which plants give off water vapour through openings in their leaves
42
How is water lost
Mainly - stomatal opening in leaves Water used during photosynthesis Water retained in cells for support Water produced through respiration
43
When will plants wilt
Water loss exceeds water uptake | Leaves and stems lose turgor pressure
44
Conditions for plants to wilt
Hot Sunny Windy
45
How does temperature affect rate of water uptake in plants
More temperature More kinetic energy Faster diffusion, evaporation and osmosis
46
How does humidity affect water uptake in plants
More humid More water vapour in the air Decreases water potential gradient Less water molecules diffuse out the cell
47
How does wind speed affect rate of water uptake in plants
Wind speeds increases Water vapour on surface of leaf is blown away Water potential gradient in and out the leaf increases Higher rate of diffusion
48
How does light intensity affect rate of water uptake of plants
More light intensity Rate of photosynthesis in guard cells of stomata increase Stomata more likely to open Higher rate of diffusion of water from leaf
49
How to prove water is lost from leaves
Anhydrous cobalt paper Dark blue - no water Pink - absorbs water
50
How to measure water loss
Measure loss of mass over time Need layer of oil on surface of water to prevent evaporation Shoot cut underwater to ensure air doesn't enter xylem
51
How to measure water uptake
Use a potometer | Rate of water uptake = length of bubblexpi(radius) squared / time taken
52
What is translocation
Process of moving the products of photosynthesis from where they are made or stored to other parts of the plant
53
What is main mechanism of phloem transport
Mass flow hypothesis
54
Mass flow hypothesis during daytime?
1. Glucose produced during photosynthesis- SOURCE. Glucose converted into sucrose 2. Sucrose is passed into phloem sieve tubes through a number of routes 3. Water potential of sieve tubes lowered 4. Water moves into sieve tubes from xylem through osmosis (hydrostatic pressure increases close to source so sieve tube contents move down tube whilst carrying sucrose) 5. Roots and growth points have high requirements for glucose for storage/respiration SINKS. Sucrose is unloaded into tissues where it's converted into glucose/starch/ other carbohydrates 6. Increasing sugar concentration in the tissues of sinks lowers water potential and water moves out the phloem via osmosis 7. Excess water enters xylem
55
Mass flow hypothesis during the night
* no photosynthesis * all tissues need glucose for respiration - become SINKS * storage organs become SOURCE * translocation direction is reversed
56
Evidence against mass flow hypothesis
• real hydrostatic pressure not as high as calculated • sieve plates slow down transport through sieve tubes and reduce hydrostatic pressure • The mass flow hypothesis suggests that ATP is only involved in the loading of the sieve tubes and that movement through the sieve tubes is passive - evidence shows that sieve tubes use ATP along their whole length and this suggests that the process is active. • It has been found that substances move in opposite directions at the same time in the same phloem sieve tube. • Some substances move at different rates in the same sieve tube even when moving in the same direction.
57
Alternative theories mot mass flow
Electro-osmosis Cytoplasmic streaming Protein contraction/ peristalsis All active
58
Investigating translocation through ringing
Removing bark and phloem from stem OR Leaving different widths of bark intact • wider strip = higher mass of carbohydrate transported to lower parts of the plant Concluded • transport from leaves must be in phloem - swelling above removal of phloem • sugars must be transported in phloem - top of shoot unaffected so obtaining sugars for respiration and other materials for growth - lower part of stem and roots grow less well as sugars dont get to them from leaves
59
Investigating translocation through use of radio-isotopes
Exposing leaves to radioactive CO2 Substances made of photosynthesis would be radioactive - becomes exposed under X-ray Black regions in phloem Concluded • transport of carbon compounds from leaves is bi-directional - above and below site of photosynthesis using 14CO2 • photosynthesis products transported in phloem - radioactive compound only detected in phloem
60
Investigating translocation using aphids
Aphids feed by inserting stylet into phloem sieve tube Stylet (mouthpart) is hollow so used to feed on sugar-rich contents of phloem If aphids anaesthetised body can be removed and leaving stylet in place Fluid is produced from cut end of stylet and can be collected Content composed mainly sugars and amino acids Rate of transpiration can be determined by exposing leaves to radioactive CO2 or roots to radioactive ions

Wjec Biology Unit 2 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions