Topic 4 (4.7 - 4.11) Flashcards

1
Q

What does the vacuole contain

A

Cell sap, a fluid mostly made of sugar (and ions) dissolved in water

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2
Q

What is the purpose of the vacuole

A

To regulate the ions in a cell
To maintain turgor pressure
To separate vascular contents from the cytoplasm

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3
Q

Why does the vacuole need to maintain turgor pressure

A

It pushes the chloroplasts closer to the cell wall

Helps support the plant cell in an upright condition

Maintains cell stability

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4
Q

How does the vacuole regulate turgor pressure

A

By regulating the ions in the cell, it can control the water potential of the cell

Increasing the water content in the cell will cause it to become turgid

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5
Q

What is the membrane that surrounds the vacuole called

A

The tonoplast

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6
Q

What is the purpose of chloroplasts

A

Photosynthesis

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7
Q

What is the structure of the chloroplast

A

Contains a double membrane with a small intermembrane space between the two

Contains thylakoids stacked into granum

Contains stroma ( a liquid making up most of the chloroplasts volume)

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8
Q

What are thylakoids

A

Small interconnected sacks that contain the membranes upon which the light dependent reaction occurs

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9
Q

What are grana

A

Stacks of thylakoids

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10
Q

What is the stroma

A

An aqueous fluid in chloroplasts
It makes up the majority of the chloroplasts volume and is responsible for the light independent stage

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11
Q

What are amyloplasts

A

Small organelles responsible for the synthesis and storage of starch

It is a double bound organelle

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12
Q

What are pits (plant cells(

A

Gaps in the cell wall where lignification is not complete, allowing water to flow between xylem vessels

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13
Q

What is the middle lamella

A

A pectin layer that joins (glues) adjacent cells together

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14
Q

What are plasmodesmata

A

Thin strands of cytoplasm that hold adjacent cells together, allowing substances to be transported between them

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15
Q
A
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16
Q

What is the xylem

A

A vessel made from hollow, dead cells that transports miners ions and water from the roots to the leaves

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17
Q

Describe lignification

A

During the development of the xylem vessel, lignin impregnates the wall of xylem cells

This kills the xylem cells, and causes the end walls and cell contents to decay

This creates a long hollow column of dead cells

18
Q

Other than killing the xylem cells, what does lignin do

A

It makes the xylem tube waterproof
It strengthens the wall, and prevents the xylem vessel from collapsing

19
Q

Why is lignin deposited in a spiral

A

To provide strength and flexibility.

The spiral shape allows the xylem to stretch and bend as the plant grows

20
Q

Why does lignification not occur in some parts of the xylem vessels

A

To create BORDERED PITS, allowing water to pass between adjacent xylem vessels

21
Q

Why are xylem vessels needed

A

Without them mineral ions could not be transported around a plant

Mineral ions (e.g magnesium) are needed for the plant to function (making chlorophyll))

Water is needed for photosynthesis

22
Q

Why is the xylem lumen narrow

A

It ensures the forces of attraction are able to pull the water up the walls of the xylem

23
Q

How does water move in the xylem

A

Via capillary action

Hydrogen bonds form between the water molecules (cohesion)
Hydrogen bonds form between the water molecules and xylem wall (adhesion)

Due to surface tension (and cohesion / adhesion) the water is pulled upwards)

24
Q

What is the phloem

A

The vessel responsible for the transport of assimilates (moslty organic materials) in a plant

It transports frim source to sink

25
What are assimilates
Substances made by plants
26
What makes up phloem tubes
Sieve tube elements line end to end There are sieve plates between the sieve tube elements Each sieve tube element is attached to a conpanion cell
27
What are sieve tube elements
Cells that contain no nucleus (or other organelles) and very little cytoplasm They are mostly empty, so that cell sap can move along the phloem vessel The end of sieve tube elements is perforated (sieve plates) so that cell sap can move between cells
28
Why does the phloem contain companion cells?
The sieve tube elements do not have mitochondria The companion cell is abundant in mitochondria for cellular respiration This produces ATP that can be used for active processes such asa loading assimilates into the phloem
29
How are companion cells and sieve tube elments connected
Through a plasmodesmata
30
Why is there a plasmodesmata between the sieve tub elements and companion cells
To allow assimilates to be transported to the companion cells (e.g so glucose can be used in respiration)
31
What is a vascular bundle
A structure in a plant containing, phloem tubes, xylem vessels and schlerenchyma
32
Where is the xylem in the vascular bundle
On the inside
33
Where is the phloem in the vascular bundle
On the outside
34
Where is the sclerenchyma in the vascular bundle
Behind the phloem
35
What is the purpose of sclerenchyma
To provide additional stupport and structure
36
Why do leaves only abosrb blue - violet and red light
Absorbing all light would cause the plant to overheat Enzymes required for photosynthesis would dneature and the cell wall would melt
37
Why are phosphorous ion needed in plants
To make ADP and ATP
38
Why are magnesium (mg2+) ions needed in plants
To produce chlorophyll
39
Why are nitrate ions needed in plants
To make DNA and amino acids
40
Why are ca2+ ions needed in plants
Too form a metal pectate for the middle lamela
41
What is a pectate
A chelators that causes metal ions to bond together
42