Biology Sa Ii Lesson 1

Front 1

Where are plants rooted to?

Back 1

Plants are rooted to 1 place.

Front 2

How do plants absorb water and where does this water go to?

Back 2

Plants absorb water from the soil using their roots, which then reaches the leaves.

Front 3

What is water used for in leaves?

Back 3

In leaves, water is used for photosynthesis.

Front 4

Unlike animals, what do plants not have?

Back 4

Unlike animals, plants do not have blood to transport substances from one part to another in their body.

Front 5

What is included in the transport system in plants?

Back 5

The transport system in plants includes absorption and conduction of water and minerals, and transportation of food.

Front 6

In unicellular plants such as Volvox or Chlamydomonas how does transportation of substances take place?

Back 6

In unicellular plants such as Volvox or Chlamydomonas, transport of substances takes place by the process of diffusion through the cell surface.

Front 7

What is diffusion?

Back 7

Diffusion is the process of movement of molecules from a region of their higher concentration to a region of their lower concentration.

Front 8

Describe the mechanism of transport in higher plants.

Back 8

The mechanism of transport in higher plants is very elaborate.

Front 9

What network of tissues is present in plants?

Back 9

There is a network of conducting tissues in plants.

Front 10

What are the conducting tissues in plants known as?

Back 10

The conducting tissues in plants are known as xylem and phloem.

Front 11

What does the xylem tissue conduct, and from which place to which place?

Back 11

The xylem tissue conducts water and minerals from the roots to the leaves.

Front 12

What does the phloem tissue conduct, and from which place to which place?

Back 12

The phloem tissue conducts food from the leaves to all parts of the plant.

Front 13

Together, what are the xylem and phloem tissues known as?

Back 13

Together, the xylem and phloem tissues are known as vascular bundles.

Front 14

What do the roots of plants absorb and from where?

Back 14

The roots absorb water and minerals from the soil.

Front 15

What is present at the tips of roots?

Back 15

There are millions of root hairs present at the tips of the roots.

Front 16

The root hairs are in close proximity to which place, and how does this help?

Back 16

The root hairs, being in close proximity to the water in the soil, help in increasing the surface area for absorption of water.

Front 17

What are root hairs?

Back 17

Root hairs are single celled protuberances of some cells in the outermost layer of the root.

Front 18

What are the root hair cells covered with?

Back 18

The root hair cells are covered with a thin cell wall.

Front 19

Beyond the cell wall lies what, and this allows and prevents the movement of which molecules of which substances to pass through it?

Back 19

Beyond the cell wall lies the cell membrane, that allows the movement of water molecules through it but prevents the movement of large molecules of other substances.

Front 20

What is the cell membrane that allows only certain molecules of certain substances to pass through it known as?

Back 20

Such a type of membrane is known as a semipermeable membrane.

Front 21

The vacuoles of cells of a semipermeable membrane are filled with a fluid known as?

Back 21

The vacuoles of cells of this region are filled with a fluid known as cell sap.

Front 22

By which process does water enter the root hairs?

Back 22

Water enters the root hairs by the process of osmosis.

Front 23

What is osmosis?

Back 23

Osmosis is the process by which the molecules of a solvent, such as water, move from a region of its higher concentration to a region of its lower concentration through a semipermeable membrane.

Front 24

Why does water enter the root hair cells by the process of osmosis?

Back 24

Since the concentration of water is high outside the root hair cells than the concentration of water inside the cells, water enters the root hair cells through the semipermeable membrane by the process of osmosis.

Front 25

In very dilute solutions, how are some of the minerals in plants absorbed?

Back 25

Some of the minerals are absorbed along with water in very dilute solutions.

Front 26

How is most of the mineral requirement of a plant met by?

Back 26

Most of the mineral requirement of a plant is met by diffusion and by the process of active transport.

Front 27

When the concentration of minerals in the soil is higher than that in the cell sap, how can minerals be absorbed?

Back 27

When the concentration of minerals in the soil is higher than that in the cell sap, minerals can easily be absorbed by simple diffusion.

Front 28

Can minerals also be absorbed even when their concentration is higher in the cell sap?

Back 28

Minerals can also be absorbed even when their concentration is higher in the cell sap.

Front 29

What is active transport and what does it require?

Back 29

The process of movement of mineral molecules from a region of lower concentration to a region of higher concentration requires utilisation of energy and is called active transport.

Front 30

The absorption of water is affected by several factors such as?

Back 30

The absorption of water is affected by several factors such as the quantity of water in the soil, soil temperature, concentration of soil solution and the quantity of air in the soil.

Front 31

Once water enters the root hair cell, where does it move to, how, and where does it reach finally?

Back 31

Once water enters the root hair cells, it moves to the deeper parts of the root by cell-to-cell osmosis and finally reaches the xylem of the root.

Front 32

Where do the minerals absorbed by the roots reach?

Back 32

The minerals absorbed by the roots reach the xylem.

Front 33

Where are the water and minerals which are absorbed by the roots conducted to, and by what?

Back 33

Water and minerals which are absorbed by the roots are conducted upwards to the aerial parts of the plant by the xylem tissues.

Front 34

What is ascent of sap?

Back 34

The upward flow of water and minerals from the roots to the aerial parts of the plant is known as ascent of sap.

Front 35

What is the water absorbed by the root utilised for in plants?

Back 35

The water absorbed by the root is utilised for various activities in plants.

Front 36

Where is most of the water absorbed by the root lost through?

Back 36

Most of the water absorbed by the root is lost through the leaves.

Front 37

What is transpiration?

Back 37

The loss of water in the form of water vapour from the aerial parts of the plant is known as transpiration.

Front 38

Where does transpiration primarily occur?

Back 38

Transpiration primarily occurs through the stomata in leaves.

Front 39

What is stomata?

Back 39

Stomata are minute openings present on the surface of the leaves.

Front 40

Where is stomata mostly present on the leaves?

Back 40

Stomata are mostly present on the lower surface of the leaves.

Front 41

As a result of transpiration, what is created, and where?

Back 41

As a result of transpiration, a suction force is created in the xylem tissue.

Front 42

The strong force of cohesion (attraction) between the water molecules helps the water how?

Back 42

The strong force of cohesion (attraction) between the water molecules helps the water to be raised as an unbroken column into the xylem tissue.

Front 43

What is transpiration pull and what is it sufficient for?

Back 43

The suction pressure (strong force of cohesion between the water molecules, helping the water to be raised as an unbroken column into the xylem tissue), is also known as transpiration pull, is sufficient to raise the water column even up to the tip of tall trees.

Front 44

What are the factors affecting the rate of transpiration?

Back 44

The factors affecting the rate of transpiration are sunlight, temperature, wind and humidity.

Front 45

How does sunlight affect the rate of transpiration?

Back 45

The rate of transpiration is faster on a sunny day as the opening of the stomata is influenced by light.

Front 46

How does temperature affect the rate of transpiration?

Back 46

The rate of transpiration is faster on a hot day as the rate of evaporation is faster.

Front 47

How does wind affect the rate of transpiration?

Back 47

Moderately blowing wind increases the rate of transpiration as water vapour is removed quickly from the leaves.

Front 48

How does humidity affect the rate of transpiration?

Back 48

On a humid day, the rate of transpiration reduces as the air is already laden with water vapour. On the other hand, if humidity is less, transpiration is more.

Front 49

State 3 ways transpiration helps the plant.

Back 49

1. Transpiration helps to maintain the concentration of the cell sap inside the plant cells. The roots continuously absorb water from the soil. If excess water is not removed, the cell sap would be diluted, preventing the further absorption of water.

2. Transpiration creates a transpiration pull that helps in the ascent of sap.

3. Transpiration also provides a cooling effect. Water lost by the process of transpiration gets evaporated. The heat required for evaporation is obtained from the plant itself and this enables the plant to keep cool.

Front 50

The upward movement of water from where to where mainly occurs through?

Back 50

The upward movement of water from the roots to the stem and leaves mainly occurs through the xylem.

Front 51

Why are the xylem vessels of the roots, stems and leaves interconnected?

Back 51

The xylem vessels of the roots, stems and leaves are interconnected so that water absorbed by the roots reach the leaves, where it is used for photosynthesis.

Front 52

What happens to the water filled in the xylem vessel?

Back 52

The water filled in the xylem vessel is raised up as an unbroken column from the root the leaves.

Front 53

What is continuously lost during the process of transpiration?

Back 53

Water is continuously lost from the leaves during the process of transpiration.

Front 54

When water is continuously lost from the leaves during the process of transpiration what does it create?

Back 54

When water is continuously lost from the leaves during the process of transpiration it creates a sort of suction pressure which pulls the water column up from the roots to the tips of the leaves.

Front 55

Describe xylem tissue.

Back 55

Xylem is a complex conducting tissue.

Front 56

What is the xylem tissue made up of?

Back 56

The xylem tissue is made up of 4 types of components - xylem vessels, xylem parenchyma, xylem fibers and tracheids.

Front 57

What are xylem vessels?

Back 57

Xylem vessels are dead cells with various types of thickenings in their cell walls. They are elongated cells, joined end-to-end, forming a long tubular structure from roots to different parts of the plant.

Front 58

What are tracheids?

Back 58

Tracheids are elongated dead cells with various thickenings in their walls, just like xylem vessels. Along with upward conduction of water, they also provide mechanical support to the plant.

Front 59

What is xylem parenchyma?

Back 59

Xylem parenchyma is the only living component of xylem, that helps in conduction of water and minerals, and also in the storage of food.

Front 60

What are xylem fibers?

Back 60

Xylem fibers are dead cells that provide only mechanical support to the plant. In the xylem, water moves upwards through the xylem vessels because of root pressure and the pressure or pull created by transpiration.

Front 61

Food is mostly prepared in which part of the plant?

Back 61

Food is mostly prepared in the green leaves.

Front 62

During photosynthesis what is glucose converted into?

Back 62

Glucose prepared in the leaves during photosynthesis is converted into starch.

Front 63

What is translocation of food?

Back 63

The movement of food from the leaves to the different parts of a plant is called translocation of food.

Front 64

How are food materials transported throughout the plant?

Back 64

The food materials are transported throughout the plant by the phloem tissue.

Front 65

What is the phloem tissue made up of?

Back 65

Phloem is made up of seive tubes, companion cells, phloem parenchyma and phloem fibers.

Front 66

What are seive tubes?

Back 66

The seive tubes are living, enucleate (no nucleus) elongated cells with perforated cross walls, which are placed end-to-end to form a tubular passage throughout the plant. These perforated cross walls are known as seive plates.

Front 67

What are companion cells?

Back 67

Companion cells are thin-walled, living cells and are found attached laterally to the seive tubes. These cells have granular cytoplasm and help the seive tubes in translocation of food.

Front 68

What is phloem parenchyma?

Back 68

Phloem parenchyma are thin-walled living cells which help in storage of food.

Front 69

What are phloem fibers?

Back 69

Phloem fibers are formed of dead elongated cells and help in providing mechanical strength to the plant.

Front 70

Apart from the requirement of elements for photosynthesis, why do plants require certain other substances?

Back 70

Apart from the requirement of elements for photosynthesis, plants also require certain substances for their normal growth and development.

Front 71

What are the substances a plant needs for their normal growth and development?

Back 71

The substances a plant needs for their normal growth and development are called nutrients.

Front 72

How are nutrients available to plants?

Back 72

Nutrients are available to plants from the soil, water and air in the form of minerals.

Front 73

Give examples of a few important mineral elements which are required by plants.

Back 73

Examples of a few important mineral elements which are required by plants are nitrogen, magnesium, potassium and phosphorus.

Front 74

In what form are important mineral elements taken by plants?

Back 74

Important mineral elements like nitrogen, magnesium, potassium and phosphorus are taken by plants in the form of compounds.

Front 75

In what form are important mineral elements taken by plants?

Back 75

Important mineral elements like nitrogen, magnesium, potassium and phosphorus are taken by plants in the form of compounds.

Front 76

What are mineral nutrients required by plants in large quantities known as?

Back 76

Some mineral nutrients are required by plants in large quantities and are known as macronutrients. Ex : Oxygen, hydrogen, nitrogen, potassium and phosphorus.

Front 77

What are mineral nutrients required by plants only in trace quantities known as?

Back 77

Some mineral nutrients are required by plants only in trace quantities and are called micronutrients. Ex : Copper, zinc, iron, molybdenum and manganese.