Plan Bio section (3 lectures)

Question 1

Plant cell general features

Answer 1

1. lots of conserved features when comparing to animal cells or fungal cells (conserved organelles, structures, metabolism+process, genes)
2. Plant cells are glued together by the cell wall (no cell migration)
3. Aren’t as many cell types compared to animal cells (~50 diff types of plant cells)

Question 2

Individual plant cells can

Answer 2

de-differentiate, divide, and form a complete plant

Question 3

DNA particle gun

what is it used to make+ step + blast

Answer 3

• Used to make transgenic plants
• After bombardment, cells that contain the transgene are selected and induced to form complete plants with each of their cells containing the transgene
• Take DNA of interest and blast it into the plant cell

Question 4

Root hair cytoplasmic streaming (3)

purpose+ organelles +cytoplasm

Answer 4

• Theres a lot of cytoplasmic streaming inside root hair to transport materials
• Organelles within the root hair are acting on actin filaments
• These organelles are moving the cytoplasm and moving nutrients.

Question 5

Organization of vesicular transport at the plant Golgi stacks

Answer 5

• The myosin motors bind to actin filaments and utilize ATP hydrolysis to generate the necessary force for movement. This movement is directional and can transport vesicles towards specific regions within the cell.

Question 6

The plant Golgi stacks move along —- that are associated with ER

Answer 6

• actin filaments
• Plant Golgi stacks are mobile organelles that can travel along actin filaments.

Question 7

Model for ER-to-Golgi vesicle transport in plant cells

Answer 7

Move throughout the cytoplasm near the plasma membrane

Question 8

Plant myosin XI

Answer 8

The fastest myosin (takes 35 nm steps)
movement drives cytoplasmic streaming

Question 9

Chloroplast move in response to light in leaf cells (3):

dim+ bright+ movement is directed by

Answer 9

• Dim light Chloroplasts align perpendicular to the direction of light. In the dim light, want to use as much sunlight as possible.
• Bright light Chloroplasts align parallel to the direction of light. In bright light, chloroplasts hide behind their neighbours because light is too intense
• Chloroplast movement is directed by light intensity

Question 10

Chloroplast movement is triggered by blue wavelengths of light (2)

move on….

Answer 10

• Chloroplasts avoid the blue light, causing it to move
• Organelles move on actin filaments using myosin motors

Question 11

Plant cytoskeleton

Answer 11

• MTs and actin filaments are conserved
• No intermediate filaments
• Motors: myosin and kinesins (no dyneins)
• Kinesins are plus and minus ended
• There are no centrioles or centrosomes. The microtubial (MTOC) organizing centers are on the surface of the plasma membrane and on the nuclear envelope

Question 12

Four plant microtubule arrays: interphase cortical array (3)

found in + amount + location

Answer 12

• found in interphase
• found up against to the plasma membrane
• only 1 present in interphase

Question 13

Four plant microtubule arrays: Per-prophase band (4)

What it is + what it does x 2+ where it forms

Answer 13

• a transient band of microtubules in pre-prophase that predicts the plane and position of the new cell wall
• forms right under (touches) the plasma membrane
• the preprophase band also functions in properly orienting the mitotic spindle, and contributes to efficient spindle formation during prometaphase

Question 14

Four plant microtubule arrays: Mitotic spindle

Answer 14

involved in pulling of sister chromatids

Question 15

Four plant microtubule arrays: Phragmoplast (2)

during…+ what it does

Answer 15

• a plant cell specific structure that forms during late cytokinesis.
• This complex assembly of microtubules, actin filaments and associated molecules acts as a framework for cell plate assembly and subsequent formation of the future cell wall separating the two daughter cells

Question 16

Plant cell wall (4)

who has it+ weight%+ all plants have what/loca+many have a ….

Answer 16

• All plants have a cell wall
• Make up about 15-30% of dry weight of a plant cell
• All plant cells have a primary wall, synthesized just outside the plasma membrane (extracellular)
• There are many plant cells that have a secondary wall, this is made after the primary wall, and it lies internal to the primary wall (still extracellular)

Question 17

secondary cell walls are composed of

Answer 17

lignin and cellulose

Question 18

Middle lamella (2)

What it does + made of

Answer 18

• a cementing layer between the primary walls of adjacent cells
• composed of pectic polysaccharide

Question 19

Cell turgor pressure (3)

What it is + important for+ high solute concen means

Answer 19

• Turgor pressure is the internal pressure (caused by water) within plant cells
• Within the cell, between the vacuole and the rest of the cell , there’s high solute concentration. Therefore water will move (osmosis) into the cell (high internal pressure)
• Important in maintaining leaf shape

Question 20

4 components of a cell wall: Cellulose microfibrils (3)

what is it made of+ structure

Answer 20

• Long polymers of glucose
• Held together by beta(1-4) linkages
• These bundle together to form a microfibril

Question 21

4 components of a cell wall: Hemicellulose (3)

Function (does it by..)+ composed of +made in+length

Answer 21

• Function to crosslink adjacent microfibrils. Does this by using hydrogen bonding because they are reversible and easier to break
• They are composed of glucose and another sugar (can be xylose or arabinose)
• Made in Golgi bodies
• not as long as cellulose

Question 22

4 components of a cell wall: Pectins (4)

what it is + function x2 + made in

Answer 22

• Branched polysaccharide
• Functions to determine the porousity of the wall, more pectin= more pourous
• Also binds proteins in the wall
• Made in Golgi bodies

Question 23

4 components of a cell wall: proteins (4)

important for stable+important for loose+ made in + move thru

Answer 23

• Important for wall stability (stablize H-bonds between hemi and CMF)
• Important for loosening the wall (loosening H-bonds between hemi and CMF)
• Proteins made in the RER
• Move through Golgi and then to plasma membrane through vesicles

Question 24

Synthesis of the wall: cellulose

Answer 24

• Cellulose microfibrils are made in the plasma membrane by cellulose synthase (rosette)

Question 25

Rosettes formation | movement determined by+ what it does

Answer 25

- Important for making the microfibril, take glucose from inside of the cell, to produce cellulose microfibrils on the outside - Rosette moves through membrane, this is determined by the cortical microtubules

Question 26

cells cannot grow ---- but can grow ----

Answer 26

laterally vertically

Question 27

Cytokinesis of plant cell | phragmoplast

Answer 27

- phragmoplast is the complex arrangement of microtubules, microfilaments and it along with golgi derived vesicles make the cell plate - phragmoplast job is to transport Golgi derived vesicles to newly developed cell plate

Question 28

Interphase

Answer 28

Non dividing cell

Question 29

Prophase

Answer 29

Chromosomes begin to condense

Question 30

METAPHASE

Answer 30

condensed chromosomes line up at the equator

Question 32

Anaphase

Answer 32

sister chromatids seperate

Question 33

Telophase

Answer 33

New nuclear envelopes begin to form

Question 34

MT and phragmoplast arrangement (2) | arrangement + how vesicles are moved

Answer 34

- Arranged so the + end of the MT are towards the center of the phragmoplast - Uses kinesin motors to move vesicles to the + end of the MT

Question 35

Plasmodesmata (3) | formed during+ structure/function+ trapped

Answer 35

- Form during cell division - microscopic channels (small tubes that connect plant cells to each other, providing living bridges between cells) which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them. - ER trapped between in the new cell wall

Question 36

The standard lytic vacuole (3)

Answer 36

- Role in regulating pH - Has low pH - degrading role

Question 37

Protein storage vacuoles

Answer 37

- store protein that can be used as food reserves for budding seeds

Question 38

Functions of plant vacoules (5):

Answer 38

* Important for storage of ions, organic acids, sugars, proteins etc. This is important in turgor pressure because you have high solute concentration * Digestion (similar role to lysosomes in animal cells) Turnover of cellular components * In pH and ion homeostasis, pH is less than 5.5 within the vacuole These have proton pumps that regulate pH of the cytoplasm * Defence vacuole can accumulate toxic compounds (ex: phenolics and alkaloids) to release in face of pathogen * Storage store ions, organic acids, sugars, proteins