3rd Midterm
Biology 101 with Casper at University of Pennsylvania
About this deck
By: Gabriela Moreno
Textbook:
Life: The Science of Biology, Vol. II
Life: The Science of Biology, Vol. III
Created: 2010-12-16
Size: 160 flashcards
Views: 55
Textbook:
Life: The Science of Biology, Vol. II Life: The Science of Biology, Vol. IIICreated: 2010-12-16
Size: 160 flashcards
Views: 55
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teosinte
ancestor of corn
artificial selection
breeding desirable traits and keeping the desirable progeny
vegetative vs seed propagation
vegetative: grafting shoots to roots
scion vs stock
seed: seeds only inherit genes from shoot
scion vs stock
seed: seeds only inherit genes from shoot
cons of traditional plant breeding
unrelated plants cannot be crossed
transgenic organism
organism created via genetic engineering methods
agrobacterium tumefaciens
plasmid used in genetic engineering to carry gene of interest
good for eudicotyledons
bad for monocotyledons
good for eudicotyledons
bad for monocotyledons
other methods of transferring agrobacterium
electroporation
injection
injection
reason plants can regenerate
totipotency
ability of a cell to divide and differentiate into all the kinds of cells found in that organism
ex: callus (undifferentiated carrot cells)
ability of a cell to divide and differentiate into all the kinds of cells found in that organism
ex: callus (undifferentiated carrot cells)
CaMV35s
popular promoter used to facilitate gene transcription
recombinant
combining two or more gene sequences that would not normally appear together, typically through genetic engineering
protoplast
cell. had its cell wall completely degraded via mechanical or enzymatic means.
some protoplasts from unrelated plants can be fused
some protoplasts from unrelated plants can be fused
bt toxin
derived from bacillus thuringiensis, plants engineered with it are more resistant to insect pests and reduce need for chemical insecticides
Name 5 modifications of roots...
prop roots
pneumatophores
buttress roots
strangling aerial roots
storage roots
pneumatophores
buttress roots
strangling aerial roots
storage roots
Name 4 modified stems...
Stolons: horizontal connections
Bulbs
Tubers
Rhizomes: horizontal, found underground, sends out roots and shoots: ex: ginger
Bulbs
Tubers
Rhizomes: horizontal, found underground, sends out roots and shoots: ex: ginger
Name 5 modified leaves...
Tendrils
Spines
Storage leaves
Reproductive leaves
Bracts
Spines
Storage leaves
Reproductive leaves
Bracts
cotyledon
significant part of embryo within seed of plant
Name the role of tannins and where they are found?
Found in red oak acorns, chemicals that help protect against seed predators and help prevent tree decay
What is the radicle?
The young root in a seed.
Name the 3 main types of plant tissue... and their main role...
Dermal - outer covering
Vascular - conducting tissue and associated cells (made up of xylem and phloem)
Ground (fundamental) - makes up bulk of plant
Vascular - conducting tissue and associated cells (made up of xylem and phloem)
Ground (fundamental) - makes up bulk of plant
What is cambium?
Layer or layers of tissue aka lateral meristem from which secondary growth can occur.
Name the 2 types of cambium...
Cork and vascular
What does xylem transport?
Water and nutrients
What does phloem transport?
Organic nutrients, mainly sucrose
What is the primary cell wall in plants made of? Why is it difficult to digest
cellulose, bonds between beta glucose monomers
What is the secondary cell wall in plants made of? A polymer of ...
lignin, a polymer of phenols, irregular shape
Cellulose comes together to form...
Microfibrils
Name the 3 types of ground tissue?
Parenchyma
Collenchyma
Schlerenchyma
Collenchyma
Schlerenchyma
Name 5 important characteristics of parenchyma cells...
1.thin and flexible primary walls
2.no secondary walls
3.retain ability to divide and differentiate
4.are the least specialized
5.perform the most metabolic functions
2.no secondary walls
3.retain ability to divide and differentiate
4.are the least specialized
5.perform the most metabolic functions
Name 4 important characteristics of collenchyma cells...
1.cola...grouped in strands which help support young parts of the plant shoot
2.thicker and uneven cell walls
3.lack secondary cell walls
4.flexible support, w/o growth restriction
2.thicker and uneven cell walls
3.lack secondary cell walls
4.flexible support, w/o growth restriction
Name 2 important characteristics of sclerenchyma cells...
1.cells are rigid because of lignin in secondary cell walls
2.dead at maturity
2.dead at maturity
Name the 2 types of sclerenchyma cells...
1.Schlereids
2.Fibers
2.Fibers
What 4 factors affect the rate of transpiration in a leaf?
leaf vapor density - air vapor density /
stomata resistanc + boundary layer resistance
stomata resistanc + boundary layer resistance
What is the function of tracheids? Where are they found?
Water transport, in xylem.
What action does the Transpiration-Cohesion-Tension Mechanism describe?
The mechanism of water movement up the plant via the xylem and under negative pressure. Some adhesion between water cells and xylem cells (capillary action).
When is new xylem formed and why is it so important?
In the spring in perennial eudicots. New xylem is important because cavitation tends to form in the xylem water pathway which breaks the stream of negative pressure pulling water up.
What is guttation? and why does it happen?
The movement of water up the xylem at night. Happens because of positive pressure exerted by roots since water continues to enter into them.
Is water potential in the roots low or high? Why?
Higher solute concentration in root means water potential is lower, and water flows from high to low.
Name the 3 transport routes between cells...
Symplastic
Transmembrane
Apoplastic
Transmembrane
Apoplastic
Is xylem part of apoplast or symplast?
apoplast
How is water movement across cell regulated?
Aquaporin transport proteins regulated by phosphorylation
What is the last checkpoint for selective passage of minerals from cortex into vascular tissue?
The endodermis
Where is Casparian strip located? what is it made of? and what does it block?
Endodermal wall. Waxy. Blocks passage of water and nutrients via apoplastic route.
What route must water and nutrients take to cross from cortex into vascular tisssue? What is the purpose of this?
Symplastic route. Water travels via xylem (apoplast), Casparian strip forces it to take symplastic route, which acts as another cell membrane checkpoint and controls what may cross.
Name 3 main essential elements in plants...
Potassium
Nitrogen
Phosphorus
Nitrogen
Phosphorus
Name 5 things of which Nitrogen is a component...
Nucleic acids
proteins
hormones
chlorophyll
coenzymes
proteins
hormones
chlorophyll
coenzymes
Name 3 major functions of Potassium...
Water balance
Stomata open and close
Cofactor in protein synthesis
Stomata open and close
Cofactor in protein synthesis
Phosphorus is a component of which 4 things?
Nucleic acids, phospolipids, ATP, several coenzymes
Name the 3 soil particles types from largest to smallest...
Sand
Silt
Clay
Silt
Clay
Give another name for the A horizon and list its 3 components...
Topsoil. Living organisms, mineral particles, and humus (decaying organic material)
Name 2 important characteristics of the B Horizon...
less organic materials
less affected by weather
less affected by weather
Essentially, what is the C horizon?
partially broken down rock
What are micelle soil particles made of ?
humus and clay
Name one measure of soil fertility and some components that make it possible...
Cation exchange capacity,
Potassium, NH4
Potassium, NH4
What is another name for negatively charged ions?
anions
Why can they not bind to soil particles?
Soil particles are negatively charged so they repel other negatively charged ions.
Name 2 important effects of pH on soil...
pH affects solubility of nutrient anions
cations more available in slightly acidic soil, roots make environment slightly more acidic
cations more available in slightly acidic soil, roots make environment slightly more acidic
What are 2 common reactants that cause acidic rain to form? What acid do they make?
Sulfur dioxide and Nitrous oxide = sulfuric acid
What happens to water potential as soil particle size decreases and water is held more tightly?
Water potential decreases
What soil particle is water attracted to?
Clay
What are the most fertile topsoils made of and what are they called?
Loams, equal amounts of sand, silt, and clay
Describe the mutual relationship between Mycorrhizal funghi and host plant?
Mycorrhizal fungi facilitate soil nutrient uptake while benefiting from host plant's supply of carbon.
What are Mycorrhiza fungi made of ?
root and fungus
What does AMF stand for? What is 1 important characteristic?
Arbuscular Mycorrhizal fungi
Spores are produced asexually and underground
Spores are produced asexually and underground
Give the name of the swellings along a legume's roots...
nodules
Nodules are composed of plant cells infected by what nitrogen fixing bacteria?
Rhizobium
What form do Rhizobium bacteria assume inside the root nodule?
Bacteroids
Where are bacteroids contained?
Inside vesicles of root cells.
Describe the transfer going on between the bacteria of a root nodule and the plant.
Bacteria obtain sugar and supply plant with fixed nitrogen.
Name 3 alternate ways of getting nutrients...
Epiphyte - get nutrient from rain and air
Insectivorous
Parasitic - on roots or shoots
Insectivorous
Parasitic - on roots or shoots
Give examples of parasitic plants...
Mistletoe (shoots)
Indian pipes (roots)
Indian pipes (roots)
Give 2 examples of epiphytes...
Staghorn ferns
Pitcher plants
Pitcher plants
Review the Calvin Cycle
do it.
Name a weakness of C3 plants in regard to carbon at high temps...
They are not good at capturing it.
What component of light independent reactions in the Calvin cycle can also act as an oxygenase?
Ribulose biphosphate oxygenase
What 3 things do higher temperatures mean for photorespiration?
1. Photorespiration is more likely to occur
2. Less CO2 dissolved in cell water
3. Rubisco is more likely to act as an oxygenase
2. Less CO2 dissolved in cell water
3. Rubisco is more likely to act as an oxygenase
What does initial fixation of CO2 via rubisco form in most C3 plants?
3 Carbon compound
What happens differently in photorespiration ?
Rubisco adds O2 instead of CO2
Describe the output of photorespiration and how it differs from normal Calvin outputs...
Photorespiration releases CO2
Does not produce ATP or sugars
Does not produce ATP or sugars
Name an important enzyme in C4 plants carbon fixation...
PEP carboxylase
phosphoenolpyruvate
phosphoenolpyruvate
What does the combination of PEP and CO2 yield, given PEP carboxylase?
Oxaloacetate
Name 3 components of C4 plants not found in C3 plants...
Bundle sheath cells
Stoma
Substomatal chamber (air space)
Stoma
Substomatal chamber (air space)
What do CO4 plants use to minimize cost of photorespiration? What does it yield?
They incorporate CO2 into 4 carbon compounds in mesophyll cells
What enzyme is required to do this?
PEP carboxylase
Why does this enzyme work?
PEP carboxylase has a higher affinity for CO2 even when concentrations are low.
Where are the 4 carbon compounds exported to once produced?
Bundle sheath cells
What is the main role of the bundle sheath cells?
Hold 4 carbon compounds which release Co2 that goes into calvin cylcle.
Where are C4 plants most abundant? Give an example of one...
High light, high temp, semi-arid environments
Corn
Corn
What does CAM stand for and what is a characteristic of plants that have it...
Crassulacean Acid Metabolism
Plants capture CO2 at night, release CO2 into Calvin cycle during day
Plants capture CO2 at night, release CO2 into Calvin cycle during day
What happens during the day for CAM plants?
Stoma closed, plants use stored CO2
What does water use efficiency depend on?
rate of carbon gained via photosynthesis vs water lost through transpiration
Carbohydrates are transported across long distances in the form of ...
sucrose
Most green plants store carbohydrates in the form of ...
starch
What is sucrose?
disaccharide of glucose and fructose
What is starch?
polysaccharide of glucose monomers
What is the difference between the glucose monomers in starch vs cellulose?
starch - linear, alpha glucose
cellulose - one rightside up, one righside down, beta glucose
cellulose - one rightside up, one righside down, beta glucose
Name 2 different forms of starch...
1. amylose
2. amylopectin
2. amylopectin
Define translocation...
process of moving sugars in the phloem
Name 3 important components of translocation in the phloem...
1. sieve tube element
2. sieve plate
3. companion cells
2. sieve plate
3. companion cells
What is the purpose of the sieve plates?
Facilitate movement of fluids between cells.
Name 2 important features of both sieve tube element and companion cells...
1. Sieve tube elements - living, contain no nucleus, ribosomes, vacuole, and cytoskeleton
2. Companion cells - living, do contain nucleus, ribosomes, and many mitochondria
2. Companion cells - living, do contain nucleus, ribosomes, and many mitochondria
Name 2 pathways through which sucrose may enter sieve tube element...
Across membrane, or plasmodesmata in companion cell
Name the 4 steps of translocation...
1. load sugar
2. load water
3. unloading sugar
4. recycle water
2. load water
3. unloading sugar
4. recycle water
What kind of pressure drives translocation?
positive pressure, flow goes down
Describe the movement of sucrose across a membrane...
Sucrose moves through cotransporter which also channels H+ ions from high concentration to low concentration. Proton pump on the other hand uses ATP energy to transport H+ ions from low to high concentrations.
What happens at the sink?
Concentration of sucrose is higher than outside of sieve tube so sucrose leaves via diffusion.
What 3 other things can be transported via the phloem?
1. Electrical signals
2. Viruses
3. Macromolecules, RNA, hormones, signal molecules
2. Viruses
3. Macromolecules, RNA, hormones, signal molecules
What 3 things can cause plasmodesmata to change in permeability?
1. Turgor pressure
2. Cytoplasmic calcium levels
3. Cytoplasmic pH
2. Cytoplasmic calcium levels
3. Cytoplasmic pH
What is the effect of plant viruses on plasmodesmata?
Dilation
What drives plant growth?
turgor pressure
What does being annual mean for a plant?
It completes its growth cycle in a year.
What does biennial mean?
the plant requires two or fewer growing seasons
What are meristems made of ?
Embryonic tissue
What kind of growth do meristems allow for?
indeterminate
Where are apical meristems located?
tips of roots and shoots
at axillary buds of shoots
at axillary buds of shoots
What is the function of apical meristems?
elongate shoots and roots
primary growth
primary growth
Where are lateral meristems located?
Inside stems
What is the purpose of lateral meristems?
add thickness to woody plants
secondary growth
secondary growth
What two things do meristems give rise to?
Initials and derivatives
What happens to initials?
They stay in the meristem
What happens to derivatives?
They become specialized in developing tissues
What is the role of the apical bud?
protection of main shoot meristem
What is the role of the axillary bud?
protection of branch shoot meristem
Name the 3 zones of a root...
1. zone of differentiation
2. zone of elongation
3. zone of cell division (root cap and apical meristem)
2. zone of elongation
3. zone of cell division (root cap and apical meristem)
What is the function of the root cap?
protection of the root apical meristem
From where do lateral roots arise?
from the pericycle
From where do leaves arise?
leaf primordia along sides of apical meristem
What happens to the meristematic cells left at the base of leaf primordia?
They develop into axillary buds
Name 2 types of lateral meristem?
Vascular and cork cambium
What is the role played by vascular cambium?
adds layers of vascular tissue called secondary xylem(wood) and pholem
What is the function of the cork cambium?
Replaces epidermis with periderm, which is tougher and thicker
Describe the cells that make up the vascular cambium...
Meristematic cells one cell layer thick
Develops from undifferentiated parenchyma cells
Develops from undifferentiated parenchyma cells
An interesting note, xylem typically consists of either vessels or tracheids. However both can be found in where?
flowering plants (vessel elements)
Why does wood formed in the spring have thin cell walls?
To maximize water delivery
Why does late wood in the fall have thicker cell walls?
stem support
What does the bark consist of ?
everything from periderm to cork cambium (includes secondary phloem)
What is the role of lenticels? and where are they located?
allow for gas exchange between living stem or roots and outside,
located in periderm
located in periderm
What are the 3 steps in the signal transduction pathway?
1. reception
2. transduction
3. response
2. transduction
3. response
What is the one main component in reception?
Receptors (proteins)
Who are the main players in transduction and what 2 things do they do?
Second messengers
1. transfer signals
2. amplify signals from receptors to proteins that will trigger responses
1. transfer signals
2. amplify signals from receptors to proteins that will trigger responses
What are the 2 ways that the signal transduction pathway can increase enzyme activity?
transcriptional regulation
post translational modification
post translational modification
What is etiolation?
When plants are grown without exposure to light
What does cGMP mean? What is its role in the signal transduction pathway?
cyclic Guanosine Monophosphate
Phytochrome is a receptor protein activated by light, it communicates with cyclic Guanosine Monophosphate ( a second messenger) which transfers signal and activate a specific protein kinase
Phytochrome is a receptor protein activated by light, it communicates with cyclic Guanosine Monophosphate ( a second messenger) which transfers signal and activate a specific protein kinase
What is the role of Ca2+ levels in the signal transduction pathway?
Phytochromes activated by light communicate with Ca2+ channel, opening it and allowing ions to transfer signals again to a specific protein kinase
specifically cytoskeletal proteins and enzymes
specifically cytoskeletal proteins and enzymes
What is the response step then?
Protein kinases activate transcription factors in nucleus triggering transcription, then translation outside of nucleus, then de-etiolation (greening response proteins)
What 2 things does transduction often involve?
1. Protein kinases that phosphorylate proteins
2. Protein phosphates that de-phosphorylate proteins
2. Protein phosphates that de-phosphorylate proteins
What are the 2 effects of such enzyme activities?
1. Can regulate transcription
2. Can modify proteins post-translation
2. Can modify proteins post-translation
What is the difference between positive and negative transcription factors?
Positive transcription factors are proteins that increase the transcription of specific genes while negative TF are proteins that decrease the transcription of specific genes
What does post-translational modification involve ?
modification of existing proteins in signal response
phosphorylation of specific amino acids
phosphorylation of specific amino acids
What function do hormones play in signal transduction pathway? What 3 key aspects do they affect?
plant growth regulators
they affect division, elongation, and differentiation of cells
tropism
they affect division, elongation, and differentiation of cells
tropism
Define tropism...
greek tropos - to turn
any response resulting in curvature of organs towards or away from a stimulus
any response resulting in curvature of organs towards or away from a stimulus
What was the main topic of Charles Darwin and his son Francis' experiment in late 1800s?
phototropism
What were the results?
Postulated that coleoptile tip hit by sunlight will cause grass seedling to bend toward light because coleoptile transmits signal to zone of elongation.
What did Peter Boysen-James demonstrate in 1913?
The signal to the elongating zone is a mobile chemical substance.
Who took the experiment even further? What did he discover?
Frits Went. Extracted chemical messenger for phototropism known as auxin
Define auxin and 3 noteworthy characteristics...
Any chemical that promotes elongation of coleoptiles
1. Auxin transporter proteins move the hormone from the basal end of the cell to the apical end of the neighboring cell
2. moves from tip of shoot to base
3. only certain concentrations of auxin work in cell elongation
1. Auxin transporter proteins move the hormone from the basal end of the cell to the apical end of the neighboring cell
2. moves from tip of shoot to base
3. only certain concentrations of auxin work in cell elongation
Give an example of a common auxin...
indoleactic acid (IAA)
Where are auxin transporter proteins located? What is their function?
In xylem parenchyma at base of cells. Function is to move auxin out of cells.
Describe the acid growth hypothesis...
Auxin stimulate proton pumps that lower the pH in the cell wall. This causes expansins to be released that break the hydrogen bonds between cellulose microfibrils and crosslinking polysaccharides. The microfibrils are loosened and can slide so the cell elongates.
How does expansion rely on turgor pressure?
Increasing the proton gradient increases ion uptake into the cell. This lowers water potential and caused water to flow in. The increase in turgor pressure and the plastic cell wall allows for cellular expansion.
What other 5 functions does auxin perform?
Root formation
Root branching
Herbicide (overdoses kill eudicots)
Affects secondary growth by increasing cell division vascular cambium and promoting differentiation in secondary xylem
Gravitropism
Root branching
Herbicide (overdoses kill eudicots)
Affects secondary growth by increasing cell division vascular cambium and promoting differentiation in secondary xylem
Gravitropism
About this deck
By: Gabriela Moreno
Textbook: Life: The Science of Biology, Vol. II
Life: The Science of Biology, Vol. III
Created: 2010-12-16
Size: 160 flashcards
Views: 55
Textbook:
Life: The Science of Biology, Vol. II Life: The Science of Biology, Vol. IIICreated: 2010-12-16
Size: 160 flashcards
Views: 55
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have used this website for three exams, and I see a huge difference in my test results.”
Naj
Naj