Exam 2 Flashcards
What is dormancy?
The seed will germinate when environmental conditions are right
What is the quiescent phase?
A resting phase followed by germination
What happens during seed maturation?
Food stores build up, the seed dessicates, and the seed coat hardens
What are meristems?
Growth tissue
What are the three tissue types?
Vascular tissue, dermal tissue, and ground tissue
What is the apical-basal pattern of growth?
Upwards and downward growth. Apical is up, basal is down?
What are the two patterns of plant growth?
Apical-basal and radial
What is embryogenesis?
Formation of the embryo
What are gymnosperms?
Vascular plants with seeds but no fruit or flowers
What are eudicots?
Plants with two cotyledons
What are monocots?
Plants with a single cotyledon
What are the types of angiosperm?
Monocots and eudicots
What are angiosperms?
Vascular plants with flowers, seeds, and fruit
What are the two types of vascular plants?
Angiosperms and gymnosperms
Define vascular.
Networks of cells that move water and sugars throughout the plant
What is step 3 of speciation?
Reinforcement in the form of secondary contact. The populations return to sympatry and any hybrid offspring have reduced fitness
What is step 2 of speciation?
Divergence. The populations must diverge genetically
What is allopatric speciation?
Geographic isolation
What is step 1 of speciation?
Isolation of populations
Where does primary growth occur?
Tips of roots and shoots (apical & basal meristems)
What is after-ripening dormancy?
Requires environmental changes (ex: vernalization)
What is embryo dormancy?
Hormone ratios prevent germination
What is coat-imposed dormancy?
When the seed coat prevents water and oxygen from entering the seed.
What is a point mutation?
A change in a single base pair.
What is a population bottleneck?
When a population crash occurs and the survivors become the founders of a new population.
What is the founder effect?
When a small number of individuals leave a larger population and start a new population, the allele frequencies are likely to be different
What is disruptive selection?
Heterozygote is less fit than homozygote
What is balancing selection?
The heterozygote is more fit than either homozygote, maintaining both alleles in the population
What is directional selection?
One allele is favored over other alleles. The favored allele will be driven to fixation while the others will be driven to loss.
Name the 4 postulates of evolution through natural selection.
- Individuals within a population show variation within a trait.
- Some of the variation is inherited by offspring.
- Individuals have different reproductive and survival success.
- Survival and reproduction are not random with respect to the trait.
Define migration.
Changes in allele frequency within different populations of the same species due to migration.
Define mutation
Creates new alleles
Define genetic drift
Random chance movement of allele frequencies
Define selection
External agent applies selective pressure that influences which genes are passed on to the next generation
Name the four mechanisms of evolution.
Migration, mutation, genetic drift, and selection.
Define microevolution.
Small-scale changes within populations over time.
What is hybridization?
When separate species can produce viable offspring.
What is interbreeding?
Producing fertile offspring.
What is the biological species concept?
A group of potentially interbreeding organisms that are reproductively isolated from all such other groups.
What is the phylogenic species concept?
Evolutionary history based on unique character states. Organism must be related to other members of a species.
What is the morphospecies concept?
Distinct morphological differences define species; based on appearance and other comparable traits.
How do we recognize a species?
Biological species concept, phylogenic species concept, and morphospecies concept.
What is an adaptation?
A trait that evolves by natural selection for a particular function that increases fitness.
What is gene flow?
The transfer of alleles from the gene pool of one population to the gene pool of another.
How does polyploidy occur?
Mutation causes production of diploid gametes, then tetraploid offspring create diploid gametes.
List some causes of dormancy.
Coat-imposed dormancy, embryo dormancy, and after-ripening
What is a dominant allele?
An allele that is expressed whenever it is part of the genotype.
Define phenotype.
The physical manifestation of a genotype in a particular environment.
Define genotype.
The genetic makeup of an individual at one or more genes.
Define heterozygous.
Individual with different alleles on each chromosome.
Define homozygous.
An individual with the same allele on both chromosomes.
What is an allele?
One of the alternative forms of a single gene at a single locus.
What is a locus?
The position the gene occupies on a chromosome.
What is a gene?
A sequence of DNA that codes for a specific protein or RNA
Define meiosis.
The process by which a diploid cell becomes four haploid cells.
Define asexual reproduction.
The process by which a single individual produces viable offspring.
Define sexual reproduction.
The process by which two individuals contribute genetic material to viable offspring.
What is the third stage of the Calvin Cycle?
Some of the PGAL comes back as RuBP and is cycled through the Calvin Cycle again.
What is the second stage of the Calvin Cycle?
PGA is reduced to PGAL
What is the first stage of the Calvin Cycle?
CO2 fixed to RuBP is hydrolyzed to form 2 PGA molecules.
What is the duplication of the entire genome called?
Polyploidy.
What is the duplication of a whole chromosome called?
Trisomy
What are the four types of chromosomal mutation?
Deletion, duplication, inversion, and translocation.
What are chromosomal mutations?
Alterations to a region of chromosome.
What is a frame-shift mutation?
Insertion/deletion of a base pair.
What is a non-sense mutation?
A change in a stop/start codon.
What is a mis-sense mutation?
A change in amino acid.
What are the types of non-synonymous mutations?
Mis-sense, non-sense, and frame-shift
What are silent/synonymous mutations?
The base pair changes, but the amino acid does not.
Name the pyrimidines.
Cytosine and thymine
Name the purines.
Adenine and guanine.
Describe DNA structure.
double helical structure with a sugar phosphate backbone and nucleotide-pair rungs
What is created from asexual reproduction?
Clones
When does physical linkage occur?
When two or more genes on the same chromosome do not sort independently.
Describe independent assortment.
During meiosis, the separation of characters on different chromosomes into different gametes, independent of each other.
Define segregation.
During meiosis, alternate alleles of a single gene separate out into different gametes.
What is a recessive allele?
An allele that is expressed only in the homozygous genotype.
What are the five types of genetic manipulation?
Selective breeding, radiation breeding, transgenics, cisgenics, and subgenics.
What are genetically modified organisms?
Organisms that contain genes from an unrelated species.
What is a callus?
A mass of dividing cells that form where a stem is cut and begin growing roots.
What is biotechnology?
The manipulation of living organisms and their components to produce useful products.
What are SINEs and LINEs
Short and long interspersed nuclear elements; highly repetitive strings of DNA
What are the types of noncoding DNA?
SINEs and LINEs, introns, and telomeres & centromeres
What does tRNA do?
works with rRNA and binds to one type of amino acid
How many “words” are in the DNA “language”?
64
How many bases code for a stop codon?
every 3
What is the purpose of mRNA?
Complementary to DNA and tRNA, but replaces thymine with uracil. Transcribes information from DNA.
What is mRNA?
messenger RNA
What does topoisomerase do?
Prevents twisting and kinks during DNA unwinding.
What does helicase do?
unwinds the DNA strand.
What does DNA polymerase do?
Adds new nucleotides to unzipped DNA strand.
What does semi-conservative replication mean?
Each original strand of DNA becomes half of a new strand of DNA.
What is chlorophyll B?
An accessory pigment to chlorophyll A
What is chlorophyll A?
Primary pigment that is key to photosynthesis.
Name three types of pigments.
Chlorophyll A, chlorophyll B, and carotenoids.
What is a pigment?
Substance that absorbs light.
What is sunlight composed of?
photons
How much less efficient is fermentation than aerobic respiration?
About 13%
What is the equation for anaerobic respiration?
Glucose + 2ADP + 2Pl –> 2 Ethanol + 2 CO2 + 2ATP + 2H2O
How many molecules of acetyl CoA can Oleic acid yield?
9
How can fats be used for the citric acid cycle?
The triglyceride molecule is hydrolyzed to glycerol and three fatty acids. Two carbon acetyl groups are then removed as acetyl CoA.
How much energy do we get from respiration?
686 kilocal or 2 ATP
How does the electron transport chain work?
High energy electrons are passed through the chain to form H2O.
List the steps of the citric acid cycle.
- Pyruvate passes from cytosol into mitochondrion.
- An acetyl group is attached to CoA
- Acetyl CoA combines with oxaloacetate
- The oxidation of carbon converts ADP to ATP and NAD+ to NADH
- FAD is reduced to FADH2
The citric acid cycle is also known as what?
The krebs cycle.
What is glycolysis?
10 step anaerobic process occurring in the cytosol that forms ATP and NAOH
List the steps in respiration.
Glycolysis, citric acid cycle, oxidative phosphorylation.
For what processes can glucose provide energy for?
Both anaerobic and aerobic processes.
In glucose oxidation, electrons move from ______ energy, to ______ energy
high, low
Define macroevolution.
Large scale changes that lead to speciation or higher-level diversification
Define evolution.
Change in allele frequency in a population over time.
What is subgenics?
Removing genes from a species.
What is cisgenics?
Moving genes within a species.
What is transgenics?
Moving genes from one species to another.
What is radiation breeding?
Mutating organisms in order to increase genetic variation.
What is selective breeding?
Only allowing the most valuable phenotypes to reproduce.
What does glucose oxidation do?
Removes hydrogen atoms from carbon atoms and combines the hydrogen with water.
What is respiration?
The complete oxidation of sugars and other molecules to carbon dioxide and water.
How do plants store energy?
As sugars and starches.
What is the calvin cycle?
photosynthesis.
Which photosystem can operate independently?
Photosystem I
What is photosystem II and what are the steps followed within it?
Pair of chlorophyll A molecules, peak absorption is P680.
- light energy is absorbed by P680 molecules in reaction center.
- Photon excites electron, electron steps through several processes, then releases energy.
Which two processes are involved in photosynthesis?
light reactions and carbon fixation reactions.
What are carotenoid pigments?
They are pigments that take a different spectrum of energy in and transfer it to chlorophyll A.
What is ground tissue composed of?
Parenchyma, collenchyma, and sclerenchyma
What are the five general types of plant cells?
Parenchyma, collenchyma, sclerenchyma, xylem, and phloem.
Describe fibers.
Long, slender sclerenchyma cells arranged in threads.
Describe slereids
Short and irregular sclerenchyma cells with thick lignified secondary walls.
What are the two types of sclerenchyma cells?
Fibers and Sclereids
Describe sclerenchyma cells.
Rigid due to thick secondary walls strengthened with lignin.
Which cells are dead at functional maturity?
Sclerenchyma, xylem
Describe collenchyma cells.
Thick, uneven cell walls that provide flexible support without restraining growth.
What does it mean to be totipotent?
To retain the ability to divide and differentiate.
Describe mature parenchyma cells.
Thin and flexible primary cells, large central vacuole, totipotent. Store nutrients and photosynthesize.
What is the periderm?
Secondary protective tissue composed of cork, cork cambium, and phelloderm.
List the functions of trichomes.
Water absorption, insect defense, reduced thermal stress, secrete salt
What is the cuticle?
Wax coating on epidermis exposed to air.
What is the epidermis?
Outside layer of leaves, flowers, fruits, seeds, and young roots and shoots.
What does each sieve tube element have instead of organelles?
A companion cell
What are sieve plates?
Porous end walls that allow fluid to flow between cells along the sieve tube.
Describe phloem as sieve-tube elements.
Lack organelles and nucleus to allow an easier flow of sugars
Describe xylem as vessel elements.
shorter cells with a larger diameter that are aligned end to end to form vessels. The end walls have perforation plates.
Describe tracheids.
tubular, elongated, and dead xylem. water travels via pits in tracheids
What are perennials?
Plants that live for many years.
What are biennials?
Plants that require two growing seasons.
What are annuals?
Plants that complete their life cycle in a year or less/
What is determinate growth?
Some plant organs cease to grow past a certain size.
What is indeterminate growth?
Growing throughout an organisms life.
What does cork cambium do?
Replaces the epidermis with periderm which is thicker and tougher.
What does vascular cambium do?
adds secondary xylem (wood) and secondary phloem.
What do lateral meristems do?
add thickness to woody plants.
