Bio Module 3 Exam

Primary cell wall

Thin flexible, allows for growth

Secondary cell wall

Thick, rigid contains lignin, provides strength

Middle Lamella

sticky layer between cells, how plants connect to one another works as an adhesive to bind to other cells

Plasmodesmata

Tiny holes on the cell wall that allow for cells to communicate to each other

Parenchyma Cells

Most common plant cell, thin and flexible walls

Function: photosynthesis, storage, metabolism

can divide and become other cells (most cells start as parenchyma and “evolve” into the other cell types)

Collenchyma Cells

Has a thick cell wall, does have a secondary cell wall

Provides flexible support

Find it in young plants or the tip of the root because we have active mitotic growth (also in the tips of leaves)

Sclerenchyma Cells

Thick secondary cell wall (which is strengthen with lignin) —> very strong and rigid (think skeleton of the plant) lignin and cellulose is like reinforced concrete

aids in support of plant

Dies once it is mature

There are two types Fibers and Sclereids

Sclerenchyma Fiber cells

Long and slender cells usually arranged in bundles for support and protection of stem and roots (think like when you break a peanut and the long fibers stick out those are fibers)

Sclerenchyma Sclereids cells

shorter then fiber cells have thick irregular and very hard secondary walls (kinda like the exterior of nuts)

Water-Conducting cells (Xylem)

Moves water and minerals upward through the plant, have thick lignified walls

Dead at maturity

two types

Two types Tracheids and Vessel elements

Water-Conducting Tracheids cells

Protection and support (rigid, lignin within the secondary wall), movement of water in upward direction, smaller than the vessel elements, dead at maturity

Water-Conducting Vessel elements cells

Rigid, lignin within secondary walls, dead at maturity

moves water faster up the Xylem because they are larger “holes” or vessels

also pits that allow water to move in and to other cells

Food-Conducting Cells (Phloem)

Transport sugars and some water (sugary sap water kinda)

two types Sieve-tube elements and Companion Cells

Sieve-tube elements

Remain alive at maturity, lack organelles

Has sieve plates (pores) that allow fluid to flow from cell to cell along the sieve tube

needs the companion cells to support it (proteins, nutrients etc.)

Companion Cells

At least one of these by every sieve cell, connected to surrounding sieve tubs by plasmodesmata, produce and transport proteins to the sieve tubes

Name the 3 plant tissues

Vascular Tissue (Xylem and Phloem)

Dermal Tissue (epidermis, stomata)

Ground Tissue

Vascular Tissue

Made up of Xylem (transports water and minerals, made of dead cells) and Phloem (moves sugar, made of living cells)

Dermal Tissue

Outer protective layer includes the epidermis, stomata (opening for gas exchange, which is controlled by guard cells)

What are the three plant organs

Stems

Roots

Leaves

What do plants have in their cells that animals don’t

Chloroplasts (which produces sugar that mitochondria use to make atp), rigid cell wall, plasmodesmata, large central vacuole

Ground Tissue

“Filler” stuff within the cell, everything in the cell that isn’t vascular or dermal tissues

Meristematic tissue

Rapidly dividing tissue, there is apical meristem(found in root tips and shoot tips primary growth), lateral meristem(secondary growth for girth, found on sides on plants)

Characteristics of Dicots

• 2 leaves when it grows

• vascular bindles are well arranged typically in a circle

• taproot root structure (straight down root)

• Net venation pattern on the leaves

• NO endosperm

• leaves are usually in multiplies of 4 or 5

Characteristics of Monocots

• 1 leaf (grass)

• Scattered vascular tissues (kinda look like alien heads scattered around)

• Fibrous root structure (roots kinda spread all over the place)

• Parallel leaf venations

• Does have endosperm (endosperm is the seeds first food source as it grows)

Where is Mesophyll located and what does it do

Located in between the upper and lower epidermis, full of chlorophyll rich ground tissue, Primary site of photosynthesis, two parts palisade(elongated and densely packed), and spongey(located lower down and irregular circular shaped)

What is a node on a plant

The point on the stem where the leaf starts to develop

What is the internode

Space on the stem between 2 nodes

What is Axillary bud

The bud/growth on the stem where the leave will grow out of

Why do leaf modifications occur

many plants evolved(like carnivorous plants) because they lived in a Nitrogen poor environment, so they need supplemental sources of nutrients

Primary Growth

Shoots growing up, and roots growing down (lengthening of the plant)

Secondary Growth

Measured in girth widening of the plant (think the bark on trees the rings are growing out which is secondary growth)

What is Determinate Growth

The organism stops growing after a certain size (animals, us!)

What is indeterminate Growth

Organism continues to grow (plants) categorized in:

Annuals - complete life after 1 year

Biannual - Complete life after 2 years (second year pant seeds)

Perennials - Live for many many years

How does secondary Xylem grow

secondary xylem grows towards interior of the plant (inward)

How does secondary Phloem grow

Secondary Phloem will be responsible for the bark so it grows outward (towards exterior of plant) (phloem flows out of plant, to remember)

What is sap-wood

outer most of the wood, it is new cells just grown so it is alive, nutrients are actively flowing through

What is heart-wood

inner most of the plant wood, dead so not providing any nutrients for the plant but it is helping support the plant

What is seed dormancy

Period of time where the seed does not grow, it waits until the condition are ideal for it to grow (hormones play a role in this)

What does the fruit and flowers do for the plant

Fruits and flowers are the “ovaries” of the plant, also aid in seed dispersal the fruit is so it attracts seed dispersers (animals) so they can take the seeds and “plant” them elsewhere

How many elements are essential for plants to survive

17 different ones a plant needs, 9 macronutrients and 8 micronutrients

What are macronutrients

Elements that are required in large amounts 9 of them in plants (C, N, O, H, K, Ca, Mg, P, S)

What are Micronutrients

Elements that are required in small amounts 8 of them (Mo, Fe, Mn, B, Zn, Cu, Ni, Na-only sometimes for this one)

What macronutrients make up 98% of the plants bio mass

C, H, O, N, S, P (Carbon, Hydrogen, Oxygen, Nitrogen, Sulfer, Phosphorus)

What is Eutrophication

When there is excessive run off of fertilizers and pesticides which end up in water and cause an algae bloom. When the algae starts to die it sinks to the bottom however when it decomposes it decreases the amount of O2 in the lower levels of the water, ultimately resulting in fish death

What is nitrogen fixation

When Nitrogen fixing bacteria takes N2 and creates NH3

What is ammonifying bacteria

Bacteria that takes NH3 and creates NH4+

What is Nitrifying bacteria

bacteria that takes NH4+ and creates NO3-

True or False

Plants cant use nitrogen gas as N2

True

What is phototropism

The plants response to light (light energy from the sun)

What is gravitropism

The plants response to Gravity

What is thigmotropism

The plants response to Touch

What is positive tropism

When a plant moves toward a specific stimulus

What is negative tropism

When a plant moves away from a specific stimulus

What are the five major hormones found in plants

Auxins, Cytokinins, Gibberellins, Abscisic acid (ABA), Ethylene,

What are Auxins responsible for

stimulating stem, and seed elongation, produced in apical meristem (tip of root and tip of shoot) aids in apical dominance → basically tells the plant to get longer (shoots go higher and root go lower)

What do Cytokines do

Cell division (cytokinesis) stimulates girth (widening of the plant)

What hormones work in antagonistic pair?

Auxins with Cytokinins, and Gibberellins with Abscisic acid

What does the Giberellin hormone do

Promotes cell elongation, and cell division at the same time used to increase growth at a specific region (i.e the fruit)

can take seeds out of dormancy

usually if you find high concentrations of it, it is from us not natural

What does Abscisic acid (ABA) do?

Inhibits growth opposite of what gibberellin says for the plant to do.

stress hormone comes into play especially when plant is dehydrated

has to be removed in order for plant to come out of dormancy

What does the hormone ethylene do

Ripens the fruit and programed cell death with bananas

Can happen naturally think bananas on counter or we can pump a warehouse with ethylene to ripen fruit faster

How does ethylene effect trees growth process

There is ethylene that is getting produced at the abscission layer which is found at the connection point of the node (connection of stem to leave) will produce ethylene and cause the leaves to fall

Circadian rhythms within plants

the plant will put its leaves down at night, hormones will put it to sleep (dictated by photoperiod→duration of light exposure (how long it was exposed to light)

What are short-day plants

flowers when daylight is shorter than the critical length

What are long-day plants

Flower when daylight is longer than critical period