Topic 9: Plant Biology

Plants have widespread influences, from food chains to climate change.

Draw a labelled diagram of the internal structure of a seed.

a

c

b

d

Testa (Seed Coat)

Cotelydon

Radicle

Plumule

Answer explanation

Look at the 9.4 Notes. This goes over the internal parts of a seed. We also used this in our seed dissection.

A student designed an experiment to study the transpiration through the leaves of a tomato plant (Solanum lycopersicum). Measurements were taken in the initial conditions with five leaves on a tomato shoot and then again after each of the five leaves was removed.

Question: Describe the trend in the data.

Answer explanation

This is the trend you see in terms of correlations. So is there a positive or negative correlation, or no correlation at all.

A student designed an experiment to study the transpiration through the leaves of a tomato plant (Solanum lycopersicum). Measurements were taken in the initial conditions with five leaves on a tomato shoot and then again after each of the five leaves was removed.

Question: Transpiration continued after the fifth leaf had been removed. Suggest what can be concluded.

Answer explanation

This is suggesting there are no leaves now, but still has gone through transpiration. So we know transpiration still occurred without leaves meaning it occurs also in the stem.

A student designed an experiment to study the transpiration through the leaves of a tomato plant (Solanum lycopersicum). Measurements were taken in the initial conditions with five leaves on a tomato shoot and then again after each of the five leaves was removed.

Question: State the independent variable of the experiment.

Answer explanation

This is the variable that was physically changed.

Reorder the following to show the process of water uptake and transport by plants.

• transport of water in xylem vessels; cohesion/hydrogen bonds between water molecules «allows water to be pulled up in xylem»

• adhesion of water to «leaf» cell walls/cellulose creates tension «forces»

• solute concentration inside the root is higher/water potential is lower «than in the soil»; due to active transport of ions/minerals into the root

• evaporation of water from «leaf» cell walls; water begins movement in xylem due to transpiration pull

• roots/root hairs absorb water; water is absorbed by osmosis

Answer explanation

Goes from soil to roots. But first evaporation must occur to create the suction from the roots to the xylem. Then water travels up the xylem through cohesion, and stays in the leaves through adhesion.

Match the following

• Movement of a plant toward light

• Geotropism

• Movement of roots of a plant toward gravity

• Thigmotropism

• Movement of a plant in response to touch

• Phototropism

Answer explanation

9.3 Notes on tropisms. 1 is not covered, but the other 2 are.

Label a diagram of a dicotyledonous flower.

g

h

a

b

c

d

e

f

i

Ovule

Stigma

Style

Pistil

Stamen

Sepal

Anther

Filament

Petal

Match the following.

• Responsible for secondary growth

• Auxin

• Responsible for primary growth

• Lateral Meristems

• Hormone for primary growth

• Apical Meristems

• Hormone for secondary growth

• Cytokinin

Answer explanation

9.3 notes, meristems and plant signaling

Label tissues X and Y.

a

b

Phloem

Xyelm

Answer explanation

Xylem is the inner part of the vascular bundle, while the phloem is the outer part of the vascular bundle.

The image shows part of a section through the stem of a non-woody plant. Where does transport of sucrose occur?

• A

• B

• C

• D

Answer explanation

The phloem is where sucrose is transported.