Structural Support And Force Transfer

Question 0

Function of guard cells

Answer 0

Change shape to open or close an opening in the epidermis known as a pore.

Question 1

Function of the stomata (sing. Stoma)

Answer 1

Allows carbon dioxide to enter to photosynthetically active tissues

Question 2

Trichomes function

Answer 2

Minimize water loss and regulating gas exchange in shoots
Depending on species:
1. Keeps surface cool by reflecting sunlight
2. Provide barbs or store toxic compounds
3. Trap and digest insects

Question 3

Most photosynthesis, as well as most carbohydrate storage, takes place in __________________.

Answer 3

Ground tissue

Question 4

What three distinct tissue types make up ground tissue?

Answer 4

1. Parenchyma
2. Collenchyma
3. Sclerenchyma

Question 5

Parenchyma cells

Answer 5

1. Are totipotent
2. Filled with chloroplast on leaves (main site of photosynthesis)
3. In other organs, store starch granules
4. Important in plant healing wounds
5. Important for asexual reproduction via stolons and rhizomes

Question 6

Collenchyma cells

Answer 6

1. Overall shape is longer and thinner
2. Cells walls tend to be thicker
3. Even mature cells can stretch and elongate
4. Provide structural support for plants

Question 7

Scleremchyma

Answer 7

1. Produce thick secondary cell wall
2. With a relatively thin primary cell wall
3. Cell wall contains lignin and cellulose
4. For supporting stems and other plant structures
5. Two types: fibre and sclereids
6. Usually dead by maturity

Question 8

Fibre sclerenchyma

Answer 8

• Extremely elongated

- Important in the manufacture of paper, ropes, and fabrics

Question 9

Sclereids

Answer 9

• relatively short
• variable shapes
• function: protection
• form the tough coat of seeds and thick shells of nuts

Question 10

Function and types of vascular tissue systems?

Answer 10

1. Xylem - conducts water and dissolved ions from root system to shoot system
2. Phloem - conducts sugar, amino acids, chemical signals, and other substances. Done in both directions; roots to shoots and shoots to roots.

Question 11

Types of cells found in the xylem structure

Answer 11

1. Tracheids - water conducting cells found in all vascular plants
2. Vessel elements - conducting cells found in angiosperms

Question 12

Tracheids

Answer 12

1. Long, slender cells with tapered ends
2. Has pits, gaps in secondary cell wall where there is only a primary cell wall.
3. Since they are dead, pits have no cytoplasm
4. Water moves up tracheids or side to side via the pits from cell to cell

Question 13

Vessel elements

Answer 13

1. Are shorter and wider than tracheids
2. Addition to pits, have perforations - openings that lack both primary and secondary cell wall.
3. In some species, may lack a cell wall
4. Form open pipes called vessels
5. Conducts water more efficiently than tracheids, because their width and perforations offer less resistance to flow

Question 14

Types of Phloem cells

Answer 14

1. Sieve-tube elements

2. Companion cells

Question 15

Sieve-tube elements

Answer 15

1. Long, thin cells that have perforated ends called sieve plates
2. Conducts sugars and other nutrients
3. Lack nuclei and most organelles
4. Connected to numerous companion cells through plasma desmata

Question 16

Companion cells

Answer 16

1. Connected to sieve-tube elements by plasmodesmata
2. Provide materials to maintain the cytoplasm and plasma-membrane of sieve-tube elements
3. Involved in loading and unloading carbohydrates and other nutrients into and out of sieve-tube elements

Question 17

Primary growth

Answer 17

• extends the reach of of roots and shoots

- increasing Plants ability to absorb photons and acquire CO2, water, and ions

Question 18

Secondary growth

Answer 18

• increases the width of the plant body
• increasing the amount of connecting tissue available
• providing structural support for extensive primary growth
• produces wood

Question 19

Differences between cambium (lateral meristem) and apical meristem

Answer 19

1. Cambium forms a cylinder that runs the length of a root or stem and is made up of a single layer of meristematic cells.
   In contrast, apical meristems are localized at root tips and shoot tips and are dome shaped.
2. In a cambium, cells divide in a way that increases width of roots in shoots.
   In an apical meristem cells divide in a way that extends root and shoot tips.

Question 20

What are the two types of cambium in plants that undergo secondary growth?

Answer 20

1. Vascular cambium
   - located between secondary xylem and secondary phloem
   - generates new layers of cells inside and outside; inside cells push outside cells increasing the girth of the plant
2. Cork cambium
   - located near perimeter of the stem and root
   - produces new cells to the outside

Question 21

Lenticels

Answer 21

Small, spongy openings in the bark that allow gas exchange

Question 22

What is striated muscle?

Answer 22

Muscle cells where the actin and myosin filaments are aligned in rows forming sarcomeres, giving the cells and tissue a banded appearances

Question 23

Types of muscle tissue

Answer 23

1. Smooth muscle
2. Cardiac muscle
3. Skeletal muscle

Question 24

Smooth muscle

Answer 24

1. Cells are unbranched
2. Tapered at each end
3. Organized into thin sheets (often)
4. Involuntary contraction

Unstriated - appears smooth

Question 25

Cardiac muscle

Answer 25

1. Makes up the walls of the heart, responsible for pumping blood throughout the body.
2. Contains sarcomeres and are striated
3. Have unique branched structures connecting end-end via specialized regions called, intercalated disks
   - these discs are important for flow of electron signals and heartbeat coordinations

Question 26

Skeletal muscle

Answer 26

1. Long, unbranched muscle fibers.
2. Packed with myofibrils, each containing thousands of sarcomeres
3. Striated
4. Usually attached to skeleton
5. Distinguished from smooth and cardiac muscle by being voluntary.

Question 27

Skeletal-Fiber Types

Answer 27

1. Slow muscle fibers
2. Fast muscle fibers
3. Intermediate muscle fibers

Question 28

Slow muscle fibers

Answer 28

• appear red because contains high [conc] of myoglobin, an iron-bearing pigment
• contracts slowly because myosin hydrolyses ATP at a slow rate
• have lots of mitochondria - fatigue slowly
• aerobic respiration supplies ATP

Question 29

Fast muscle fibers

Answer 29

• appear white because they have a low myoglobin [conc].
• contract rapidly - myosin hydrolyses ATP at rapid rates
• fatigue rapidly because primary source of ATP is glycolysis rather than aerobic respiration.

Fun fact: contracts up to three times faster than slow muscle fibre

Question 30

Intermediate muscle fibers

Answer 30

• appear pink or red
• contracts at intermediate speeds
• derive ATP from both glycolysis and aerobic respiration

Question 31

Types of skeletal-fibre organization

Answer 31

1. Parallel

2. Pennate

Question 32

Parallel

Answer 32

Small cross section = small force

Long length = large length change

Question 33

Pennate

Answer 33

Large cross section = large force

Small length = small length change

Question 34

Main function of skeletal systems

Answer 34

1. Protection
2. Maintenance of body posture
3. Re-extension of shortened muscle
4. Transfer of muscle forces

Question 35

Types of skeletal systems

Answer 35

1. Hydrostatic skeletons - use the hydrostatic pressure of enclosed body fluids or soft tissue to support body.
2. Endoskeleton - have rigid structures inside the body
3. Exoskeleton - have rigid structures on the outside of the body

Question 36

How do hydrostatic skeletons move?

Answer 36

Alternating contraction of longitudal and circumferential muscles pass down animals in waves, called peristalsis, allowing movement forward or backwards

Question 37

Bones

Answer 37

• human adult body contains 206
• made of cells that contain calcium phosphate
• bones meet up at articulation (joints)

Question 38

Cartilage

Answer 38

-made up of cells scattered in gelatinous matrix of polysaccharides and protein fiber

Question 39

Tendons

Answer 39

Connects muscles to bones

Question 40

Ligaments

Answer 40

• Made of collagen

- Bind bones to other bones

Question 41

How Do Exoskeletons work?

Answer 41

Same as endoskeleton but use pennate muscles