Biology unit test 2

Question 1

plant classification:

Answer 1

Domain - Eukaryotes
Kingdom - Plant kingdom
- Autotrophs (photosynthesis)
- Have cellulose, cell wall, large vacuole
- Ancestral plants transitioned from water to land plants (developed cuticles & stoma)

Question 2

importance of plants

Answer 2

Photosynthesis:
Uses CO2 in atmosphere
Gives oxygen for atmosphere (21%)
Glucose is the food that supplies plants with energy
Purifies water and move it through the water cycle

Plants Supply Cellulose:
Cellulose is a large carbohydrate molecule, it is the main component of cell walls in plants.
use:
- make fabric , cardboard / paper

source of food
Humans consume ~7,000 out of the 50,000 edible plant species on Earth!
Plants make up the base of the food chain for many organisms

plants used for medicine
indigenous medicine

source of fuel
produce energy. It is a renewable resource.

Plants Help Prevent Erosion

plants are pretty

Ecological Succession:
one community replaces another after an ecological disturbance.
- plants can survive harsh conditions

perc fem

Question 3

What is the difference between vascular plants and non-vascular plants

Answer 3

Vascular plans have xylom and phloem, nonvascular do not, because they grow close to the ground.

Vascular plants have a root in a stem and non-vascular plants do not.

Vascular plants can grow more elaborately and Taller The non-vascular plants.

Non-vascular plants can go a long time without water

Question 4

Classification of seedless plants

Answer 4

Reproduce by spores
Don’t produce flowers

Ex. Ferns, Mosses

Question 5

Classification of angiosperm/flowering plants
and
gymnoperm / non-flowering

Answer 5

The very large phylum under the plant kingdom
angiosperms = food source (fruit & seed)
ex: herbaceous plants, shrubs, grasses, most tree

seeds are considered naked or not protected by an ovary/ fruit (scandalous)
ex: conifers (spruce, pines, fir), ginkgo (biloba), cycads

Question 6

two different forms based on the structure of their seeds:

Answer 6

monocotyledon (monocot) and dicotyledon (dicot).

Question 7

Cotyledon

Answer 7

a structure in the embryo of a seed that helps to nourish a plant as it first starts to grow
Called a ‘seed leaf’ because it’s actually part of the seed (embryo) of the plant
These seed leaves serve to access the stored nutrients in the seed, feeding it until the true leaves develop and begin photosynthesizing

Question 8

% of monocots and dicots

Answer 8

Approximately 30% of all angiosperms are monocots and 70% are dicots.

Question 9

Monocot & Dicot examples

Answer 9

MONOCOTS
Grains (e.g. wheat and corn)
Daffodils
Onions
Grass

DICOTS
Legumes (e.g. peas, beans, lentils)
Daisies
Lettuce
Oak trees

Question 10

what is endosperm

Answer 10

a tissue produced inside the seeds of most of the flowering plants following fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This makes the endosperms of seeds an important food source for animals.

Question 11

what is the radical

Answer 11

the embryonic root of the plant.

Question 12

what is the seed coat

Answer 12

protects the cotyledons and endosperm.

Question 13

3 main ways of seed dispersal

Answer 13

harnessing power of wind
animal dispersal
firedispersal - fire melts & releases seeds

Question 14

Vascular Plants have 4 types of tissues

Answer 14

Dermal Tissue
The outer layers of cells that form a protective covering for the plant from herbivores, disease, injury and water loss
Includes:
Periderm: Found in older woody plants. A layer of dermal tissue that replaces the epidermis to form cork in woody stems and roots.
Epidermis: dermal tissue that forms a protective covering over the body of non-woody plants and young woody plants
Some epidermal cells are specialized to perform a specific function.
Root Hairs: tiny hair like structures that extend from the individual epidermal cells on plant roots. They increase the surface area available for absorption of water and nutrients.

Vascular Tissue
Some epidermal cells are specialized to perform a specific function.
Guard Cells: work in pairs in the lower epidermis to surround a stoma (plural stomata) and regulate their opening
Stomata = pores in the leaf that allow gas exchange to occur (H20 vapour, CO2, O2)
Internal system of tubes that run lengthwise through the stem of a plant to the roots to the leaves for transport of water and nutrients.
Two types:
Xylem: transports water and minerals from the roots the leaves
Phloem: transports nutrients such as sugar to areas where it is needed for growth and metabolism, or roots for storage

Ground Tissue
Forms most of the plants internal and external material

Has may functions:
Photosynthesis (in green parts)
Storage (carbohydrates in roots and stems)
Support – in stems

Meristematic Tissue
Undifferentiated embryonic plant tissue from which all other plant tissues develop

Plants continue to produce new cells by mitosis in their meristematic tissue

Ex. the tip of a plant’s roots and stems are constantly growing due to the division of cells in the apical meristem

Question 15

Vascular plants have 3 main non-reproductive organs:

Answer 15

Leaf
Stem
Root

Question 16

Roots serve 3 Main Functions

Answer 16

Take in water and dissolved minerals that are transported to where they are needed
Anchor the plant in the soil supporting the plant against wind and water
Store carbohydrates that are produced by photosynthesis in the leaves or green stems, as well as water and other nutrients

Question 17

types of stems

Answer 17

soft and flexible (herbaceous) to hard and rigid (wood).
function - provide support to leave & reproductive structures

Question 18

The Scientific Method

Answer 18

Usually starts with an observation that creates a question.

A hypothesis is formulated. This is what will be tested. The results gained from an experiment will either prove or disprove the hypothesis.

An experiment is designed to test the hypothesis. Ideally the experiment will minimise variables so that your results show, as clearly as possible, a cause and effect.

Collect data – most often quantitative data – numbers – length, temperature etc.

Present the data – most often charts and graphs.

Analyse the data.

Write a conclusion based on your data – was your hypothesis proven right or wrong.

Question 19

Stems & roots

Answer 19

Stems are very important structures in plants. They have several functions:
They provide a connection (think of them as a conduit) that carry vascular tissue from the roots to the leaves.
They provide support and raise plant structures. They raise leaves up to enhance exposure to sun for photosynthesis and raise up flowers to make pollination easier
In some species the stems are modified to store carbohydrate or water. For example, cacti.
If you cut through stems and observe them under a microscope there is a marked difference between the stems of monocots and dicots: Notice how the vascular bundles are scattered in monocots, whereas, in dicots the vascular bundles are arranged in a distinctive ring.

Roots are very important structures in plants. They have several functions:
They anchor the plant in the soils and help keep it upright
They absorb water and nutrients from the soil. They have special structures called root hairs that significantly increase the surface area for water absorption
Some roots store water and carbohydrate for the plant
If you cut through roots and observe them under a microscope there is a marked difference between the roots of monocots and dicots: In monocots the centre of the root contains parenchyma cells. These cells are surrounded by a ring of xylem and phloem cells. In dicots the centre of the root has an ‘X’ shaped region of xylem cells, surrounded by phloem cell

Question 20

importance of soil

Answer 20

It is the main growing medium for plants. People often overlook this importance and take it for granted. Please watch the following video and make some notes regarding the importance of soil.

Question 21

functions of Xylem & Phloem

Answer 21

Xylem: transports water and minerals from the roots the leaves
Phloem: transports nutrients (sugar) to areas where it is needed for growth and metabolism, or roots for storage

Question 22

Transport in the Plant

Answer 22

→ Water moves between the xylem and phloem
→ Sugars (from photosynthesis) are transported by the phloem
→ Nutrients in the soil transported by xylem (1 way flow)

Question 23

Transport of Water and Nutrients

Answer 23

Movement of water and nutrients from the root hair to the leaves involves three stages:
Soil → roots
Roots → stem
Stem → leaves
Same processes occurs in plants in bodies of water

Question 24

Transport in the root

Answer 24

Water enters by osmosis (diffusion of water from high to low concentration of water)
Nutrients enter by active transport (movement from an area of low to high concentration of substances against the concentration gradient )
The root cells contain a higher concentration of dissolved nutrients than the surrounding soil

Question 25

Transport into the Stem

Answer 25

As more nutrients are actively pumped into the xylem, their concentration increases, and water follows by osmosis creating root pressure - osmotic force pushing nutrients and water upwards in root vascular tissue

Question 26

Capillary action (

Answer 26

tendency of a liquid to rise or fall because of attractive forces between liquid molecules) also pulls water up from the roots

Question 27

Transport to the Leaves

Answer 27

Main driving force of transport up the xylem comes from the leaves Plants release water vapour through their stomata during transpiration (evaporation of water from leaves)

Question 28

Transport of Sugars

Answer 28

Sugars are produced by photosynthesis or from breaking down carbohydrates in storage organs Source: cell that makes sugars (ex. leaf cell) High concentration of sugars Sink: a cell where sugars are needed. Ex. developing part of a plant (where a fruit or flower is growing) or the roots for storage Low concentration of sugars' Sugars can move up or down the plant (direction depends on location of the sources relative to sink cells)] Sugars are transported by the phloem cells Concentration of sugar in phloem is generally higher than in source cells (involves Active transport) Leave phloem by passive transport (going from area of high concentration to low concentration)

Question 29

Translocation

Answer 29

the transport of sugar and other organic molecules through the phloem (2 way transport)in the plant. Moves sugars from where they are made (mesophyll) to where they are needed (sink). For example, during winter, sugar is stored in the roots. In the spring, sugar is moved back to the trunk (stem) and branches for growth/metabolism.

Question 30

Plant Growth Factors

Answer 30

A plant’s ability to grow is affected by: Sunlight Carbon dioxide Water A plant’s ability to grow is affected by: soil pH Each plant species grows best within a narrow pH range. Plants that thrive in acidic soil include pine, blueberry, and potatoes. Plants that thrive in alkaline soil include lawn grass, beans, pears, and lettuce.

Question 31

Plant Growth Factors: Hormones

Answer 31

Hormones stimulatory Hormones: Cytokinins stimulate cell division (growth, repair and replacement of cells) and Cell differentiation (cells becoming specialized) Auxins stimulate cell elongation (growth) that develops into apical dominance (growth is upward with little lateral growth) Gibberellins: also produced in apical meristem, stimulating plant growth. They promote the growth of taller, stronger plants and plants that flower early. Often used in crops to increase fruit size and cluster size Inhibitory Hormones: 4. Ethylene Gas: inhibits growth by weakening cell walls of fruit, and breaks down complex carbohydrates into sugars (causing ripening). Because ripe fruits bruise easy during transit, they are shipped unripened. Ethylene gas is used to ripen it quickly when it arrives. 5. Abscisic acid: inhibits growth by inhibiting growth of buds in the plant stem, blocking the intake of carbon dioxide by controlling the stomata and blocking growth-promoting hormones.

Question 32

Plant Growth Factors: Environmental Stimuli

Answer 32

Nastic responses: plants response to the stimulus is independent of the direction of the stimulus. It is not a growth response, it is reversible can be repeated. Ex: opening and closing of flower petals as light conditions change. Nastic responses: plants response to the stimulus is independent of the direction of the stimulus. It is not a growth response, it is reversible can be repeated. Ex: opening and closing of flower petals as light conditions change. Phototropism: a growth response to light produced by an unequal distribution of auxin. More auxin on the side with less light causes those cells to elongate and bend the plant toward the light. Thigmotropism: a growth response to touch or contact

Question 33

Auxin

Answer 33

The shoot apical meristem is the main site of auxin synthesis. Their primary role is to promote cell elongation. In the previous example the auxin is produced on the side of the shoot that is more shaded. This stimulates the plant to grow towards light, away from the shade.

Question 34

Gibberellins

Answer 34

To date, more than 100 different gibberellins have been isolated. They act on plant cells in many different ways, for example, cell division, flowering and size. Larger plants contain more gibberellin and smaller plants contain less.

Question 35

Cytokinins

Answer 35

Cytokinins stimulate cell division and are also thought to slow the aging of plant cells. Synthetic cytokinins are often sprayed onto plants to slow spoilage.

Question 36

Ethylene

Answer 36

Ethylene is a gas, sometimes called the plant stress hormone because it induces changes that protect the plant against environmental stress. For example, in drought conditions, ethylene stimulated the loss of leaves from a plant to reduce water loss. Ethylene also ripens fruit. This has great economic importance because fruit that ripens spoils faster. Farmers therefore try to minimize plant exposure to ethylene from when they are picked until they arrive at the supermarkets. Containers of fruit and veg can also be flooded with ethylene so that they all ripen at the same time.

Question 37

Abscisic Acid

Answer 37

Abscisic acid (ABA) inhibits growth. This is very important, for example, when seeds or buds need to remain dormant because environmental conditions, such as temperature, are not optimal for the plant to grow. ABA is often sprayed onto plants before they are shipped. Upon reaching their destination, they can then be sprayed with gibberellin to re-stimulate growth. ABA is the hormone that causes guard cells to close to conserve water.

Question 38

Sexual Reproduction - Seedless Plants

Answer 38

Reproduce through spores. Fertilization requires the sperm to swim from the male to the egg in the female. Thus, water must be present, and the sperm must have a flagellum.

Question 39

Pollination: sexual reproduction

Answer 39

the transfer of the male pollen grain (produces sperm) to the female reproductive structure. Occurs in both gymnosperms and angiosperms.

Question 40

Seed Plants - Angiosperms

Answer 40

Angiosperm sexual reproduction involves the flower organ. Flowers have: sepals – protect the flower bud petals – attract pollinators stamens – male reproductive structure (produces pollen grains) pistils – female reproductive structure Pollination occurs when sperm from the pollen grain lands on the stigma. Fertilization occurs when the pollen reaches the ovary.

Question 41

types of angiosperm pollination

Answer 41

Self-pollination: Plants pollinate themselves or another flower on the same plant. This can lead to loss of genetic variation and species vulnerability. Cross-pollination: Plants receive pollen from another plant, ensuring genetic diversity. Animal Pollination: Insects and other small animals move from flower to flower collecting nectar and moving pollen. Bright, sweet-smelling flowers attract these pollinators. Wind Pollination: Some plants lack colourful reproductive organs but produce large quantities of light pollen grains to increase the chances of pollen landing on a receptive reproductive organ.

Question 42

Sexual Reproduction Gymnosperms

Answer 42

The male pollen grain develops from the male organ. Fertilization occurs when the sperm unites with the egg in the female structure. This forms an embryo. The embryo and a small amount of food is covered by a tough seed coat. The seeds remain in the female structure (on the upper surface) until maturity when they are released (ex. by animal or wind).

Question 43

asexual reproduction

Answer 43

Natural Vegetative Propagation: Genetically identical copies are made of the original plant (from roots, stems or leaves) Asexual reproduction (cloning) can be an advantage when plants are well-adapted to their environment. Farmers and gardeners have studied and perfected techniques of artificial propagation that involve asexual reproduction from a plant’s roots, stems, or leaves (vegetative propagation). splitting Split the plant into 2 or more; each piece contains roots and shoots simple and inexpensive way to propagate or thin out plants Examples: bulbs (tulips), plants with more than one stem (peonies, hostas) leaf cutting a part of a leaf or entire leaf is cut and placed in growth medium (water, soil, or vermiculite) so that meristem cells can grow shoots and roots Faster than propagating from seed; can be done out of season Examples: African violets, snake plants, aloe vera stem cutting A stem or shoot tip is cut and placed in growth medium to grow roots from meristem cells Faster than propagating from seed; can be done out of season Examples: herbs (basil), gymnosperm and angiosperm trees (pine, willow), flowering bushes (roses), grapevines

Question 44

The benefits of asexual reproduction

Answer 44

If a plant has features that allow it to thrive in its environment, then all the offspring will have the same features Saves energy – no need to produce complicated structures like flowers Produces new individuals quickly Only requires a single plant – no need to depend on another plant Plantlets formed by asexual reproduction are more robust than seedlings produced by sexual reproduction. They therefore have a higher survival rate

Question 45

The costs of asexual reproduction

Answer 45

There is one huge cost – lack of genetic variation. This means that if the environment changes, there are no differences within the population to provide individuals that might survive. They would all die.

Question 46

what is Primary succession

Answer 46

occurs in an area that has no plants, animals, or soil. This process can take 100’s to a thousand years before a climax community is reached. This is because, over a long period of time, rock eventually becomes soil. It takes about 100 years to produce an inch of good topsoil.

Question 47

Secondary succession

Answer 47

can take as little as 50 years to reach a climax community. This is because the soil is already established. Since it often follows natural disasters that have devastated an ecosystem, the soil already has microorganisms and seeds contained within it that give the ecosystem a head start on rebuilding.

Question 48

what are the two types of succession

Answer 48

primary and secondary.

Question 49

Cuticle

Answer 49

waxy layer of the epidermis secreted by epidermal cells. Helps reduce water loss by reducing evaporation

Question 50

types of ground tissue

Answer 50

Ground (i) Parenchyma Thin -walled cells, living at maturity Parenchyma and collenchyma perform cellular processes to support growth and development Parenchyma store carbohydrate, especially starch Collenchyma and Sclerenchyma support and protect the plant body (ii) Collenchyma Thick-walled cells, living at maturity (iii) Sclerenchyma Cells with lignin (wood) in their cells, dead at maturity

Question 51

DIFFUSION

Answer 51

Diffusion is the movement of molecules from an area where they are in high concentration to an area where they are in low concentration. This occurs along a concentration gradient until an equilibrium is reached.

Question 52

Osmosis

Answer 52

Osmosis is a special kind of diffusion where the only molecules moving from high concentration to low concentration are water molecules. These water molecules move across/through a selective (or semi-permeable) membrane. The best example of a selective membrane is the cell membrane surrounding animal and plant cells.

Question 53

INSIDE CELL OUTSIDE CELL 80% Salt 90% Salt 20% Water 10% Water Where will the water move?

Answer 53

There is a higher concentration of water inside the cell than outside the cell. Water molecules will move from left to right. From inside the cell to the outside of the cell.

Question 54

Gravitropism

Answer 54

A directional change in growth pattern in response to gravity

Question 55

positively trophic:

Answer 55

grow towards the light

Question 56

Tropic Responses

Answer 56

a plant’s growth response to external stimulation coming from one direction of the environment