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Test 3 Flashcards

1
Q

What are constitutive genes?

A

These are housekeeping genes and they are NOT differentially regulated, meaning they are active all the time and they ALWAYS need to be expressed in order for the cell to be alive; example: metabolism genes.

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2
Q

difference between housekeeping genes and specific genes.

A

Housekeeping genes present in all tissue types – regulate processes that all cells need (think metabolism). Specific genes are specific to their tissue type

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3
Q

When does the majority of gene regulation take place?

A

Transcription

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4
Q

What is an operon?

A

An operon is a cluster of genes that are transcribed and translated together with one promoter; only prokaryotes have them

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5
Q

Why are operons helpful

A

Operons regulate which genes are being transcibed to save energy

*Can transcribe many genes at once

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6
Q

What repressible operon did we learn about?

A

Trp operon

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7
Q

What is a repressor?

A

Binds to the operator of the operon to prevent the transcription of the genes

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8
Q

What is the corepressor in the trp operon?

A

Tryptophan

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9
Q

If there is tryptophan present in the cell, is the gene for tryptophan being transcribed?

A

No, because there is tryptophan (corepressor) that binds to the repressor and causes a shape change to activate it to bind to the operator therefore hindering transcription

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10
Q

What inducible operon did we learn about?

A

The lac operon codes for genes that make the enzymes needed to metabolize lactose a type of sugar. when the inducer binds to the repressor, the repressor is removed which allows the cell to transcribe the genes needed to make the proteins that can digest lactose.

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11
Q

What is the inducer in the lactose example?

A

Allolactose

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12
Q

Is the repressor normally on or off? (in lac example)

A

On

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13
Q

If there is glucose absent and lactose present is the lac operon on or off?

A

On

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14
Q

If there is glucose present and lactose present is the lac operon on or off?

A

Off

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15
Q

What type of gene regulation are operons?

A

Transcription

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16
Q

What is gene imprinting:

A

a process in genome modification where some genes are shut down (methylated)

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17
Q

What impact does DNA methylation have on transcription?

A

Methylation will tighten the DNA onto the histone inhibiting transcription

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18
Q

What impact does DNA acetylation have on transcription?

A

Acetylation will loosen the Histones so DNA transcription is more likely

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19
Q

What are the two regulatory transcription factors?

A

Activators and Repressors

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20
Q

Activators and repressors;

A

activators enhance: facilitate the binding of RNA polymerase and transcription initiation.

repressors silence: decrease gene expression by blocking RNA polymerase from accessing the promoter and starting transcription.

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21
Q

Alternative splicing

A

*Allows for there to be many genes encoded in one transcript

*By changing what exons are included in the mRNA transcript it can change what genes are expressed and also maximize the number of genes included in one transcript

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22
Q

Constitutive exons:

A

exons always included and in the order in which they appear on the pre mRNA

Eurkaryotes

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23
Q

Alternative exons;

A

sometimes are included but other times are not always included

Eukaryotes

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24
Q

what is the advantage of alternative splicing

A

we can produce tissue specific proteins and developmental specific versions of proteins

Also allows for a single gene to produce many combinations

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25
What is quorum sensing
*Quorum sensing is the ability for bacteria to communicate with each other for the purpose of producing something; it is a way for them to alter gene expression *The bacteria are always producing signals but once the concentration of them is high enough they will alter gene expression for the purpose of producing something
26
what three things can a bacteria do if it is able to communicate with other bacteria?
They can produce biofilms, toxins, and spores, exchange genetic data
27
What stage in the cell cycle does quorum sensing occur and therefore the things that are produced via quorum sensing?
Stationary
28
Examples of biofilms in real life.
Teeth, growth in catheters, growth in pipes *can cause chronic infection
29
Why do people with diabetes usually have trouble with their feet?
Biofilms protect from antibiotics. But the antibiotics already have a hard time circulating to the feet so the biofilm provides an extra layer therefore prolonging the infection
30
endotoxins
*not actively secreted and have general symptoms of fever, lethargy, malaise; produced by the LPS of gram negative bacteria *large doses can cause hemorrhagic shock and tissue necrosis PRODUCED BY LIPID POLYSACCHARIDES OF GRAM-
31
Exotoxins
secreted and have very specific targets Made by both gram + and -
32
AB toxins;
two component exotoxins where the A component is the active toxin and the B component helps the toxin to bind to the target cell
33
Photoautotroph;
energy from the sun and makes its own C-C bonds
34
Photoheterotroph;
energy from the sun and ingests pre existing C-C bonds
35
Chemoautotroph;
energy from chemical bonds and makes its own C-C bonds
36
Chemoheterotroph;
energy from chemical bonds and ingests pre existing C-C bonds
37
lithotrophy
Ability to use inorganic molecules to generate energy and build cells; many are chemoautotrophs
38
example of lithotrophy w nitrogen cycle
ammonia oxidizers which use ammonia as a source of energy and they are critical for the nitrogen cycle to progress by oxidizing ammonia
39
Relationship between bacteria and root nodules.
All living things need lots of nitrogen but the only organisms that can fix it are bacteria and archaea; so plants (eukaryotes) have a mutualistic relationship with bacteria and archaea;
40
What type of process is nitrogen fixation
anaerobic respiration
41
2 plant systems
Shoot system, root system
42
What is the function of roots? Why do roots have root hairs?
Anchor the plant, absorb nutrients and water, store carbohydrates Inc. surface area
43
What is the difference between a taproot and a fibrous root?
Taproot: one large vertical root, many small lateral branches Fibrous: mat of slender roots spreading out
44
Explain the three components of a stem.
Nodes, internodes, buds
45
what is the purpose of a plant having modified stems, leaves, or roots?
It helps them better adapt and survive in the particular environment they are in.
46
Dermal tissue
Skin of plant
47
Vascular tissue (plants)
transports materials between roots and shoots
48
Xylem:
*transports water (vascular) *Tracheids & Vessel elements *dead at maturity
49
Phloem:
*sugars transportation (vascular) *Tube shaped living cells *Sieve tube elements *Companion cells *Alive at maturity
50
Ground tissue
bulk of plant tissue, can function in storage, photosynthesis, etc
51
Parenchyma
(photosynthetic storage cells) Ground tissue alive at maturity
52
Collenchyma
(support growth in young plants and shoots, alive at maturity) Ground tissue
53
Sclerenchyma
(support and strength, dead at maturity) Ground tissue
54
two types of meristems
Apical (primary growth, length of shoots and roots) lateral (secondary growth, increase thickness of stem in woody plants)
55
what are meristems
sites of active cell division
56
What are two ways plants respond to stimuli?
Adjust their growth, adjust their development
57
what occurs when light is detected by phytochromes.
*Produces cGMP which phosphorylates a protein kinase. This travels to the nucleus and phosphorylates and certain transcription factor. *Opens a calcium ion channel which phosphorylates a protein kinase. This travels to the nucleus and phosphorylates a certain transcription factor. *Both transcription factors initiate the transcription and translation of proteins required for the de-etiolation response. Basically transitions from dark to light growth
58
de-etiolation.
*he greening response; stem elongation slows, leaves develop, there are many chloroplasts/chlorophyll, extensive root development for water absorption. *Allows them to maximize photosynthesis.
59
Auxin Purpose
Stem elongation, enhances apical dominance, the tropisms
60
Auxin location
Shoot apical meristems and young leaves
61
Giberellins Location
Meristems of apical buds and roots
62
Ethylene Location
Produced by most parts of plant
63
Giberellins Function
Stem elongation, seed germination
64
Ethylene Function
Ripening of fruit, triple response
65
Cytokinins Location
Roots
66
Cytokinins Function
Cell division in shoots and roots modify apical dominance ( encourage lateral growth to counter auxin )
67
Abscisic acid Function
Inhibits growth, stomatal closure and seed dormancy
68
Abscisic acid Location
All over the plant (detected in all organs and living tissues)
69
Hormone involved in phototropism?
Auxin
70
gravitropism.
The growth of roots and shoots toward or away from the direction of gravity Auxin
71
apical dominance
Terminal bud’s ability to suppress development of axillary buds Cytokinin and mostly Auxin Cut top to encourage lateral growth
72
seed germination
Water diffuses into the seed and this triggers GA to be released which triggers alpha amylase. This converts starch in the cell wall to sugars that can be used by the growing seed. Giberellins
73
triple response
A plant's response to mechanical stress; slower stem elongation, thickening of the stem, curvature to horizontal growth Ethylene
74
feedback mechanism of fruit ripening
positive feedback mechanism. Ethylene causes ripening, which in turn stimulates more ethylene production.
75
conditions that would cause the stomata of a plant to be closed and how this occurs.
Drought conditions ABA causes potassium channels in the plasma membrane of guard cells to open → potassium ions diffuse out → water flows out osmotically → guard cell pressure decreases and this leads to the closing of stomatal pores.
76
How do plants tackle the problem of the soil's general charge?
Acidify the soil by releasing CO2
77
How does acidifying the soil assist in mineral absorption?
With the soil more acidic, the strong negative charge is gone and mineral cations are released.
78
Which vascular tissue do water and minerals try to get to? What are the transport cells associated with this tissue?
Xylem, tracheids and vessel elements
79
What is the Casparian strip and its function?
A waxy strip in the cell wall of endodermal cells (make up the boundary of vascular tissue) which makes endodermal cells impervious to water. Forces water to take the symplastic route through the cell. Filters things through symplastic route to be transfered to xylem in apoplastic route
80
Explain bulk flow. Is it sufficient to explain xylem transport?
The active pumping of water and minerals into the xylem causes positive pressure which forces particles up the xylem it is not sufficient
81
cohesion-tension hypothesis.
water is transported even though bulk flow is insufficient to cause it all. Water is lost at the leaves through stomata which creates negative pressure at the top of the plant. Due to hydrogen bonding, the entire column of water is “pulled” up.
82
What is transported in the phloem? What are its transport cells?
Sugar, sieve tube elements
83
Where is sucrose transported to and from?
produced in mesophyll cells produced to sieve tube elements where it can access phloem via apoplastic or symplastic route
84
How is sucrose transported into the cell? Does this require ATP?
Actively transported into the cell, YES
85
phloem transport requires a chemiosmotic mechanism, explain
ATP is used to pump H+ proteins from low to high concentration, when H+ flows down its concentration gradient it produces sufficient energy that sucrose is able to be actively transported into the cell
86
Is there a high or low concentration of sugar near the source (leaf)?
There is a high concentration near the source
87
What direction is bulk flow driven in?
Away from the source
88
When sugar needs to be used or stored, how is it transported out of the phloem?
Passively diffuses out of phloem into sink cell
89
What is the metabolism of animals?
Chemoheterotroph
90
What are the four types of animal tissues?
Muscular, epithelial, nervous, connective
91
epithelial tissues
Cover the outside of the body and lines the organs and cavities; the cells are closely packers and the basement membrane is present where it is classified based on cell shape and layers Forms skin Protection, absorption, secretion (think sweat), filtration
92
connective tissues
These are cells embedded in an extracellular matrix
93
types of connective tissue
Collagen - building block of skin/bone Mineral matrix– bone Liquid matrix– blood
94
Functions of connective tissue
Form structure Protection Bind and connect
95
nervous tissue.
Receives processes and transmits information
96
what makes up nervous system
Nervous system consists of neurons and glial cells
97
How does the way that we exchange materials with the environment differ from an amoeba?
We require systems in order to exchange our materials with the environment while the amoeba is thin enough that every cell is 0-1 cells away from the environment and can therefore utilize diffusion to do so
98
What two systems play a prominent and integral role in maintaining homeostasis?
Nervous and endocrine
99
regulator.
Control mechanism maintain internal conditions
100
conformer.
Allows internal conditions to vary with environment
101
what is shuttling? Is this a behavioral or physiological control mechanism?
Going back and forth from shaded areas to not shaded areas, behavioral
102
negative feedback? Is this a behavioral or physiological control mechanism?
Where the secreted molecule or signal inhibits the molecule that secreted it, physiological when there is deviation from a set point, think thermostat
103
Thermo regulation
If the body temperature rises: hypothalamus activates cooling mechanisms → blood vessels dilate and we sweat If the body temperature lowers: hypothalamus activates warming mechanisms → blood vessels constrict and we shiver
104
What organisms’ body temperature is determined by internal metabolism? By external environment?
Internal: endotherm External: ectotherm
105
What organisms’ body temperature is constant regardless of the external temperature? Which fluctuates?
Constant: homeotherm (mammals) Fluctuates: poikilotherm
106
Node
A node is the point on the plant stem where leaves, branches, or buds are attached. Function: Nodes serve as the anchor for the growth of leaves, flowers, and lateral branches.
107
Internode
An internode is the region of the stem between two nodes. Function: Internodes contribute to the elongation of the stem, allowing the plant to grow taller. The length of internodes can vary, affecting the plant’s overall shape.
108
Bud
A bud is an undeveloped shoot that can give rise to a new leaf, flower, or branch. There are two main types of buds: -Apical Bud (Terminal Bud): Located at the tip of the stem or branch, it is responsible for the primary growth of the plant, contributing to the elongation of the stem. -Lateral Bud (Axillary Bud): Located in the angle between the stem and a leaf (called the axil), it can develop into a branch, a flower, or a new shoot.

Biology Test 3 (9 decks)

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