Topic 3: Specialized Cells/Systems in Plants

Question 1

Tissue

Answer 1

Cells that have a similar design and function group together for a common purpose

Question 2

Organ

Answer 2

Groups of tissue that work towards a common function

Question 3

System

Answer 3

Group of organs working together to complete a more general function; several make up an organism

Question 4

Photosynthesis

Answer 4

When chlorophyll in the chloroplasts traps LIGHT ENERGY from the Sun and in a reaction from WATER (from soil) and CO2 (from air) creates GLUCOSE and O2

Question 5

Balanced reaction for photosynthesis

Answer 5

6 CO2 (g) + 6 H2O (l) + light –> C6H1206 (s)+ 6 O2 (g)

Question 6

Cellular respiration

Answer 6

The opposing reaction that occurs in plants and animal cells mitochondria to convert glucose and oxygen into usable energy (ATP) + carbon dioxide and water

Question 7

Epidermal cells

Answer 7

• secretes a waxy layer that covers the leaves and stem of a plant called the cuticle
• prevents water loss by reducing the amount that can be evaporated from the surface of the plant
• does not have chloroplasts and is transparent to allow solar energy to pass through to the parts of the leaf that actually conduct photosynthesis

Question 8

Palisade tissue cells

Answer 8

• shaped like columns and tightly packed together
• where the photosynthesis takes place

Question 9

Spongy tissue cells

Answer 9

• round and loosely packed with many air spaces in between
• carry out photosynthesis by allowing carbon dioxide to diffuse into the leaf and oxygen out
• regulate the movement of water vapor through the leaf

Question 10

Stomata

Answer 10

• Greek translation = mouth
• small openings found in the epidermal layer, surrounded by 2 guard cells
• allows gas to move in/out of the cell, allowing carbon dioxide to enter the plant and for oxygen to leave as a waste product
• regulates water loss by controlling how much can escape through the openings

Question 11

Guard cells

Answer 11

• surround the stomata, controlling the opening and closing of it by changing its shape
• water causes it to swell and the stoma opens but when water is lost, the stoma closes preventing transpiration

Question 12

Vascular tissue cells

Answer 12

• forms a series of tubes to transport fluids which is arranged into vascular bundles
• forms the phloem and xylem
• important in the development and growth of the plant

Question 13

Xylem

Answer 13

• Vascular tissue that transports water and minerals from the roots —> rest of the plant

Question 14

Phloem

Answer 14

• Vascular tissue that transports sugar from the leaves to —> rest of the plant

Question 15

Lenticels

Answer 15

• areas found on the surface of the stems and roots, allowing gas exchange to the external environment
• allows gas to diffuse in and out of the plant

Question 16

Transpiration

Answer 16

• the process by which water vapor is lost from plants in the stomata
• water is pulled from the roots through the xylem and then evaporates from the leaves
• creates a gradient pulling more water up from the roots

Question 17

turgor pressure

Answer 17

• when water enters the guard cells, the water pressure inside the cells increases causing the cells to swell (become turgid) through water flow via osmosis

Question 18

Why do the stomata open during the day and close during the night?

Answer 18

• it is open during the day because there is a lot of sunlight which is required for photosynthesis and carbon dioxide is required to enter the plant through the stomata
• it is closed at night because when there is no sunlight and the plant does not need to carry out photosynthesis, there is a potential risk of excessive water loss
• conserves water and reduces risks of dehydration

Question 19

Companion cells

Answer 19

• help phloem in carrying sap and the personal assistants

Question 20

tropisms

Answer 20

• plants have a system that allow them to respond to changes in enviroment

Question 21

phototropism

Answer 21

• plants will grow towards a light source to increase photosynthesis because cells are growing at different rates
• the stem will curve if one side of the plant is growing longer
• the tip of the plant sends signals to the stem to control rate of growth

Question 22

Auxin

Answer 22

• like the hormones in humans how they stimulate the elongation of cells
• prevents/stops the growth of root cells
• stimulates/encourages the growth of stem cells

Question 23

Gravitropism

Answer 23

• response to gravity
• negative = stem grows against gravity
• positive = stems grow towards gravity
• roots grow down - more likely to find soil, water, and minerals
  stems grow up - get the light they require for photosynthesis