Botany Lab: 4-7 [Exam Study Guide]

Which of the solutions is hypotonic to the tissue? (see lab 5 chart)

-Distilled water

How does the reaction of iodine with the potato cells compare with what you observed in your onion epidermis preparation? And why?

-During the reaction of iodine, the leucoplasts of the potato cells turned purple and into grain-like structure. However, during onion epidermis preparation, there are no purple stained leucoplasts (starch). -Iodine reacts with starch in the potato and turned the starch purple/black -Iodine stains the nucleus and turned it into orange in onion epidermis cell

How many types of plastids did you observe during this laboratory period? What is the function of each type?

-I saw 3 types of plastids: chloroplasts, chromoplasts, and leucoplasts. -The function of the chloroplast is to go through photosynthesis (chloroplast is where photosynthesis occurs). -Chromoplasts' function is to store carotenoids ---Carotenoids: any of a class of mainly yellow, orange, or red fat-soluble pigments, including carotene, which give color to plant parts such as ripe tomatoes and autumn leaves. -Leucoplasts' function is to store starch, proteins, and lipids

In what part of a cell are plastids located?

-In the cytoplasm --Cytoplasm: the material or protoplasm within a living cell, excluding the nucleus.

What is the competitive inhibitor of an enzyme?

-It is a molecule that can bind to the active site and compete with other substrates -It is also a molecule that is similar is similar to the substrate in shape and come to bind in active sites RuBP + CO2 (substrates) -> 2PGA (product)

Green pepper cells have...

-No stain -Contains cell wall and chloroplasts

Red pepper cells have...

-No stain -Contains cell wall and chromoplast

What is Sclereids?

-Sclereid is a type of sclerenchyma cell -it is part of the flesh of the pear fruit -it is often roughly spherical type -In the clusters of sclereids, there are thick secondary walls with clearly visible pits, some of which are branched --Cells with secondary walls also have primary walls

What are two types of Sclerenchyma cells?

-Sclereids -Fibers

Onion epidermis cells are...

-Stained with KI2 -Contains nucleus (orange) and yellow stained cells -Epidermis: the outer layer of cells covering an organism

How do you explain the action of the competitive inhibitor?

-The competitive inhibitor binds to the active site and competes with other substrates as the inhibitor has a similar shape with the substrates. -The competitive inhibitor prevents enzyme activity.

How many subunits (or chains) in Rubisco? How many of them are large subunits? How many are them are small subunits? Are the large subunits identical? How about the small subunits?

-There are 16 chains in Rubisco -8 are large subunits -8 are small subunits -Large subunits are identical -Small subunits are identical

You will probably see some small oval-shaped blue-black structures in potato cells after they are stained with iodine. What are they? What substance do they store? And why did they turn blue (or purple or black)?

-They are leucoplasts and they store starch, proteins, and lipids. -They turn purple because iodine reacts with starch.

In 5% salt...

-hypertonic -lose water -low turgor pressure

In 0.9% salt...

-isotonic solution -cells are in equilibrium

In 0% salt (NaCl)....

-solution is hypotonic -cells gain water -There is high turgor pressure

Which of the solutions is isotonic? (see lab 5 chart)

0.9% NaCl

Enter "1AA1" in the search box and zoom in on the active site to observe the product: What is the product of the reaction catalyzed by Rubisco? How many of them?

2 PGA is the product. There are 2 of the PGA at each active site.

Which of the solutions is hypertonic to the tissue? (see lab 5 chart)

5% NaCl

What are the two major secondary structures of proteins?

Alpha-helix and beta-sheet

What is the primary structure of a protein?

Amino acid sequence Sequence: order of amino acids

What is a polypeptide is made of?

Amino acids

Rubsico needs two substrates (substrate is the substance upon which an enzyme acts in an enzymatic reaction):

CO2 and ribulose 1,5-bisphosphate or RuBP (a five-carbon compound)

How do you determine if the color in a plant cell is due to carotenoid pigment or anthocyanin pigment?

Carotenoid pigment is yellow, orange, or red, and it is located in chromoplasts. Anthocyanin pigment is pink, purple, or blue, and it is located in the central vacuole.

What is the function of an enzyme?

Catalyzes (speeds up) chemical reactions

Collenchyma cells you examined in the alfalfa stem were part of the _________ The __________ also contains _______________ cells, many with numerous chloroplasts The ______ in alfalfa is composed entirely of _________________ cells

Collenchyma cells you examined in the alfalfa stem were part of the cortex The cortex also contains parenchyma cells, many with numerous chloroplasts The pith in alfalfa is composed entirely of parenchyma cells

Competitive inhibitor occupies the active site of Rubisco because of its _________ _________ to the substrate, preventing the binding of the _____________ and inhibiting the ______________________

Competitive inhibitor occupies the active site of Rubisco because of its similar shape to the substrate, preventing the binding of the natural substrate and inhibiting the chemical reaction

What are dermal tissues? (purpose and types)

Dermal tissue system (skin of plants; the outer layer) -Purpose: protection -2 types: ---Epidermis (thin skin; ex: tomato's skin) ---Periderm (outer bark; thick skin)

What is enzyme?

Enzyme: a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

Epidermal layer: composed of ______________ cells and representing the _______ tissue system

Epidermal layer: composed of parenchyma cells and representing the dermal tissue system

What are fibers?

Fiber: second type of sclerenchyma cell -Can be found in the Tilia (linden or basswood) or other stem sections that are one, two, and three years old. -The fibers are especially clearly visible in the bark

What is the major difference between green pepper and red pepper cells?

Green pepper cells contain chloroplast and red pepper cells have chromoplast

What are ground tissue system?

Ground tissue system (underneath dermal tissue) -Purpose: storage and every other things the other two tissues don't do / Tissue for photosynthesis -3 types of ground tissue: ---Parenchyma ---Collenchyma ---Sclerenchyma

Ground tissue: representing the _________ tissue system -Surrounds the _______________ -Can be distinguished as ________, ______, and _________

Ground tissue: representing the ground tissue system -Surrounds the vascular bundles -Can be distinguished as cortex, pith, and pith rays

Hypertonic (high solute solution): Animal cells: Plant cells:

Hypertonic (high solute solution): Animal cells: shrink Plant cells: Plasmolysis

What does hypertonic mean?

Hypertonic: solution with high solutes

Hypotonic solution (low solute solution) Animal cells: Plant cells:

Hypotonic solution (low solute solution) Animal cells: Swell/burst Plant cells: -Build turgor pressure -Plant cells never burst ---turgor pressure: the pressure exerted (to put into use) on a plant cell wall by water passing into the cell by osmosis

What does hypotonic means?

Hypotonic: solution with lower solutes

How would you distinguish among three plastids in plants under a compound microscope?

I can distinguish among three plastids under compound microscope because chloroplast has green pigment, chromoplasts have yellow, orange, or red pigment and leucoplasts are white/colorless without iodine staining but they turn purple/black with iodine staining. I can also distinguish (recognize) by looking at their shapes.

An animal cell is placed in a beaker of pure water. What will happen to the cell? What is the reason for the difference between what happens to plant and animals cells placed in pure water? If an animal cell is placed in a ____________ solution (pure water), the animal cell will swell (become larger in size) and burst. On the other hand, plant cell in _______________ will build turgor pressure. The reason for the difference between plant and animal cells in pure water is the _____________ Because of the ____________, plant cells never burst, but animal cells don't have ____________ so they burst (break open) and die.

If an animal cell is placed in a hypotonic solution (pure water), the animal cell will swell (become larger in size) and burst. On the other hand, plant cell in pure water will build turgor pressure. The reason for the difference between plant and animal cells in pure water is the cell wall. Because of the cell wall, plant cells never burst, but animal cells don't have cell wall so they burst (break open) and die.

Explain what happened to the potato cells in each solution? In ______ water, potato cells gain water and swell, and they become hard and firm. In_____________ solution, the potato piece/cells stay the same, and they are continually hard. In a ___________ solution, the potato cells lose water and they become soft and flexible.

In distilled water, potato cells gain water and swell, and they become hard and firm. In isotonic (0.9% NaCl) solution, the potato piece/cells stay the same, and they are continually hard. In a hypertonic solution, the potato cells lose water and they become soft and flexible.

What does isotonic solution mean?

Isotonic solution: two solutions having the same osmotic pressure across a semipermeable membrane. ---Osmotic pressure: the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution. ---Osmosis: a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

What is the cofactor of an enzyme?

It is an ion that is required for the activity of an enzyme For Rubisco, Mg2+ is the cofactor

Why is it important that solutions administered (applied) intravenously (taking place within a vein) be isotonic to the recipient's (a person that receives something) blood? Why would happen if the injected solution were hypertonic to your blood? Why if it were hypotonic? It is important that solutions administered intravenously be isotonic because if an injected solution were hypertonic to my blood, my blood cells will ____________ and die, and if it were hypotonic, my blood cells will __________ and die. On the other hand, if the solution was isotonic, some things in cell will go out, but the solution (substance) will go in. In an isotonic solution, cells are in ______________.

It is important that solutions administered intravenously be isotonic because if an injected solution were hypertonic to my blood, my blood cells will shrivel (wrinkle and decrease in size) and die, and if it were hypotonic, my blood cells will burst and die. On the other hand, if the solution was isotonic, some things in cell will go out, but the solution (substance) will go in. In an isotonic solution, cells are in equilibrium (substances in the cell move in equal speed in both directions).

Potato cells go through _______ staining

KI2 staining

Zoom in on the active site. What cofactor is needed for Rubisco?

Mg2+

Does drinking soda quench (satisfy) your thirst? Explain.

No, because soda has 29% of sugar, and so cells will lose water. Soda is hypertonic compared to water.

Did you see any plastids in an onion cell?

No. Because onion cell doesn't need it.

List the organelles (or structures) you saw in plant cells with a compound microscope in this lab.

Nucleus, cell wall, chloroplasts, chromoplasts, and leucoplasts

What are 3 types of ground tissue and their functions?

Parenchyma: contains cells with the thin cell wall ---Metabolically active Collenchyma: unevenly thickened cells ---Provide flexible support Sclerenchyma (dead cells): very thickened cell wall ---Metabolically not active Part of sclerenchyma: Sclereid (in pears / hard, sandy texture) Fiber cells

How are the amino acids linked in a polypeptide?

Peptide bonds

What are plastids?

Plastids: small organelles in the cytoplasm of plant cells, containing pigment or food

Principal supporting cells of the primary plant body and of young, growing organs, _______________ cells, can be found in the alfalfa stem cross sections. _______________ cells are cells with the __________ __________ walls

Principal supporting cells of the primary plant body and of young, growing organs, collenchyma cells, can be found in the alfalfa stem cross sections. Collenchyma cells are cells with the unevenly thickened walls

Ring of vascular bundles: composed of primary ________ and primary _________ and representing the ____________ tissue system

Ring of vascular bundles: composed of primary phloem and primary xylem and representing the vascular tissue system

What is Rubisco formula?

RuBP (5 C) + CO2 (1 C) [Substrate (the starting material)] ----------(Rubisco = enzyme)-----> 2 PGA (3 C) [Products]

What is the substrate that binds to the active site of Rubisco? How many carbon does the substrate have?

RuBP (5 carbons)

Does Rubisco have a quaternary structure? And why?

Rubisco have a quaternary structure because it contains more than 1 polypeptide chain.

Rubisco's large chain is coded by the gene (_______) in the ____________ DNA, and the small chain is coded by the gene (______) found in the ______ DNA

Rubisco's large chain is coded by the gene (rbcL) in the chloroplast DNA, and the small chain is coded by the gene (rbcS) found in the nuclear DNA

What is Rubisco?

Rubisco: is an essential enzyme for the Calvin cycle of photosynthesis, catalyzing (causing an action to begin) the first step, the rate (speed)-limiting step, of the cycle -Rubisco converts/changes CO2 into organic compounds (PGA) -Rubisco is one of the most important and abundant enzymes on the earth -The enzyme is composed of 16 polypeptide subunits (or chains), including eight copies of a large chain and eight copies of a small chain

What are 3 tissue systems?

The 3 tissue systems are: dermal, vascular, and ground

The activity of Rubisco can be inhibited by a _________________ (ex: XDP)

The activity of Rubisco can be inhibited by a competitive inhibitor (ex: XDP)

What has happened to the cells placed in 10% NaCl solution? The cell/plasma membrane ______ and the cell turns into ___________ cell with intracellular (occurring within a cell) space, as the water leaves the cell.

The cell/plasma membrane shrinks and the cell turns into plasmolyzed (contraction/shrinking of the protoplast (cell with cell wall removed) of a plant cell as a result of loss of water from the cell) cell with intracellular (occurring within a cell) space, as the water leaves the cell.

What has happened to the cells placed in water?

The cells build turgor pressure, and they look plump (having a full rounded shape) and healthy.

A gardener's favorite bush died several days after she applied twice the recommended amount of fertilizer. What probably happened?

The fertilizer made the soil hypertonic, which brought water out of the bush cells. This leaving of water in the cells eventually kills the bush.

Where would you expect to find a nucleolus in a plant cell? What is the function of the nucleolus?

The nucleolus is inside of the nucleus. The function of the nucleolus is to assemble (gather together) ribosomes and transport ribosomes out into the nucleus.

A plant cell is placed in a beaker of pure water. What will happen to the cell?

The plant cell will build turgor pressure, and the cell will become healthy.

What is the active site of an enzyme?

The substrate-binding site

The tissue systems are are initiated (began) during embryogenesis (the formation and development of an embryo) and are continuous in the hypocotyl-root axis and cotyledons, where they are represented by the 3 primary meristems: ______________, _____________, and ___________ ___________, respectively

The tissue systems are are initiated (began) during embryogenesis (the formation and development of an embryo) and are continuous in the hypocotyl-root axis and cotyledons, where they are represented by the 3 primary meristems: protoderm, procambium, and ground meristem, respectively Hypocotyl: the part of the stem of an embryo plant beneath the stalks of the seed leaves or cotyledons and directly above the root.

There is a thin layer of ______, the ___________, on the outer surface of the epidermis ________________ are kidney-shaped in surface view

There is a thin layer of cutin, the cuticle, on the outer surface of the epidermis Guard cells are kidney-shaped in surface view

How does the method of salt or sugar curing (a process in which meat is packed in salt or sugar) help to preserve meat?

This is because meat in salt or sugar lose water and so the meat will become dry. Dry meat prevents microorganisms from growing as there's no moisture in dry meat, and therefore, preserving (maintain in its original state) the meat.

If you are stranded (left without the means to move from somewhere) in a life-raft (plastic boat) on the ocean, you should never drink seawater, even though you may be dying of thirst. Why are not?

This is because seawater is hypertonic and so if we drink saltwater, our cells will lose water and die

In some restaurants, potato stripes are soaked in water before they are fried. Can you provide an explanation for this practice based on the result of this experiment?

This is to make the potato stripes crispy. When potato stripes are in water, they build turgor pressure and when they are fried, the texture of potato stripes is crispy.

What are vascular tissue system? (purpose and types)

Vascular tissue system (tubes/pipes in plants) -Purpose: for conduction and transportation -2 types: ---Xylem ---Phloem

When does a protein contain a quaternary structure?

When protein has more than one polypeptide chain

Enter "1RCO" in the search box and zoom in on the active site to observe the competitive inhibitor (XDP): Do the substrate and competitive inhibitor have similar shape (Figure 1B)?

Yes.

Did you see alpha-helices and beta-sheets in each of the chains?

Yes. Because all chains are identical to each other (with large subunits to each other and small subunits to each other), they all have alpha-helices and beta-sheets.

Bundles with external and internal phloem =

bicollateral

Vascular tissues: Phloem is found on ______________ of the vascular bundles in Cucurbita.

both sides

Once the two substrates are gathered in the specific location of the Rubsico's active site, __________________ is linked to RuBP to form two molecules of phosphoglycerate (3PG or PGA), converting inorganic carbon dioxide into organic compounds in the process.

carbon dioxide

In plasmolyzed cells = ___________ and _____________________ separate -__________ cell

cell wall and plasma membrane -unhealthy cell

High turgor pressure = _______ potato

hard

Potato cells contain ___________ and _______________

leucoplasts and cell wall

Onion epidermis cells are _________-free

plastids -no plastids

Low turgor pressure = ______________ potato

soft, flexible