Chapter 6: Plants Organ System - Biology

Question 1

Systems

Answer 1

In biology, it means a group of tissues and organs that perform specific functions

Question 2

Root System (Meaning)

Answer 2

An organ system which takes in water and minerals from the soil, and transports it into the shoot system

Question 3

Shoot System (Meaning)

Answer 3

An organ system that supports the plant, does photosynthesis, and transports sap

Question 4

Root System (Function)

Answer 4

• Consists of all roots that are below the surface of the ground
• Take in water and minerals from the soil
• Constantly growing in order to keep pace with the plants increased demand for more materials as it grows

Question 5

Shoot System

Answer 5

• Supports the plant by performing photosynthesis, and transporting water, nutrients, and sugars
• Sometimes flowers, and fruits are considered part of a seperate system, but they may be part of the shoot system as well

Question 6

Xylem

Answer 6

This tissue takes care of water, and minerals from roots to all over the plant including leaves where it is needed for photosynthesis

Question 7

Phloem

Answer 7

This tissue moves the sugars produced by photosynthesis to other parts of the plants

Question 8

Systems working together

Answer 8

Root, and shoot systems are connected by the water flow, nutrient, and various harmones in vasular bundles consisting of xylem, and phloem which are essential for the plant to survive

Question 9

Moving water through systems

Answer 9

Less water:
* Nutrients cannot be taken up by roots
* Nutrient molecules need to be dissolved in water in order to be absorbed, and taken up by the xylem in the form of sap
* Insufficient water supply to the leaves would lead to photosynthesis not taking place

More water:
* Spaces between the soil would be filled with water molecules resulting in not being enough room for oxygen
* Not gaining enough oxygen for cellular respiration

Keeping water balanced, and moving through the plant is important, and that will require the root, and shoot systems to be in coordination

Question 10

Moving through the roots

Answer 10

The structure of the roots help plants absorb water, and minerals through the soil
1. Epidermal cells of most types of roots grow small extensions of their cell membrane known as root hair which allows greater surface area
2. Move toward Xylem at the centre of the root
3. The endodermis helps control the water passage from the cortex to the vascular tissue
4. The water, and nutrients are then pushed into the xylem vessels

Question 11

The Effect of Root Pressure on water movement

Answer 11

*Root pressure is created under certain conditions like during night when the transpiration is low, and moist

1. As root cells bring minerals into the xylem, the mineral concentration in the xylem increases
2. High concentration of minerals increases the tendency of water to diffuse into the root xylem through osmosis
3. As water flows into the root xylem, root pressure builds up in the xylem vessels, and the pressure forces fluid up the xylem

*Root pressure can only push water up the xylem a certain distance above the ground. In cases like the giant redwood tree, it needs a much more major factor contributing to the upward movement, and that would be plant transpiration.

Question 12

The Pull from Above

Answer 12

1. Water from the soil enters the xylem in the roots or in other words, tension in the water column extends from the leaves to the roots
2. The water column is held together through cohesion, and adhesion keeps the water column in place
3. The sun causes transpiration, also known as exhalation or evaporation to occur which causes the water on the leaves to cause tension, and pulls the water from the xylem upwards

Question 13

Rate of transpiration

Answer 13

Controlled by the amount of water vapour in the leaves. If the water vapour is small, then the guard cell relaxes, and the stomata closes.

Question 14

Moving nutrients through the system

Answer 14

1. Photosynthesis produces a form of sugar known as glucose which combines with other molecules to create sucrose, and other carbohydrates.
2. Sucrose is soluble in water, and is the main molecule distributed all over the plant by traveling through phloem. When sucrose travels to the roots, it is chemically changed, and stored as strach if not use immediately.
3. When stored starch is needed by other plant organs, it is converted to sucrose which dissolves into water and trasported as sap (starch cannot be transported throughout the stem).