Bio Final Exam

Cell Theory

All living things are made of cells
All cells come from already existing cells
Cells are the most basic unit of life

Euakaryotes

Plant Cells and Animal cells (multicellular organism

Prokaryotes

Bacteria (unicellular organism)

Difference between Eukaryotes and Prokaryotes

Eukaryotes are much more complex due to the presence of membrane bound organelles

Animal Cells vs Plant Cells (differences)

Plant cells have a cell membrane and a cell wall
Plants have both mitochondria and chloroplasts
Plants have a large central Vacuole
Animal Cells have centrioles (contain mitotic spindle fibers)

Nucleus

Stores genetic information (DNA)

Rough Endoplasmic Reticulum

Facilitates the translation of secreted proteins or membrane proteins

Smooth Endoplasmic Reticulum

Synthesizes lipids, detoxifies molecules and acts as a Ca2+ storage

Free Ribosomes

Synthesizes proteins that are NOT excreted (used within the cell)

Golgi Apparatus

Packs and sends out proteins for transport, either outside the cell through exocytosis or to another organelle in a vesicle

Lysosomes

membrane bound sacks that contain hydrolytic enzymes that are used to break down organelle waste or proteins

Mitochondria

Converts glucose to ATP

Chloroplast

Converts photon energy to glucose

Plasma Membrane

Selectively permeable membrane that covers cells
- lipid bilateral that allows nonpolar molecules to pass but not polar molecules without transport proteins.

Structure -> Function

Changes in structure may lead to changes in function because the specific shapes of organelles allow them to complete their tasks more efficiently.
- Ex: Mitochondria cristae are folded in a way that gives it more surface area to perform cellular respiration

How is overall cell function dependent on organelles

Organelles and their individual membranes allow them to compartmentalize reactions therefore allowing multiple different reactions to take place at once, allowing for the efficiency necessary to maintain life.

How do prokaryotic cells divide?

Binary Fission:
- Prokaryotic cell duplicates their DNA
- FTsz proteins form a ring in the middle of the cell
- plasma membrane and cel wall materials begin to form in the middle
- once cell wall is present the cell splits into two

Eukaryotic Cell Cycle (Phases and Descriptions)

Interphase
- G1 - growth phase
- S phase - synthesis phase: DNA replicates
- G2 phase - growth phase
Mitotis
- Prophase: Nuclear membrane dissolves, DNA begins to compress and mitotic spindle begins to form
- Metaphase: Duplicated chromosomes are pushed to the metaphase plate by mitotic spindle fibers. 1 duplicated chromosome is just 1 sister chromatids
- Anaphase: Mitotic Spindle fibers pull chromatids apart
- Telophase: Chromosomes begin to lengthen and the cleavage furrow forms
Cytokinesis
- Cell splits into two and nuclear membrane reforms

Meiosis 1

Homologous chromosomes separate
-> duplicated chromosome from mom and dad make up one homologous chromosome (4 chromatids)
-> crossing over between non sister chromatids
-> goes from 2n to n
Independent Assortment of chromosomes along the metaphase plate

Peroxisomes

Detoxify substances like alchohols

Vacuoles

Fluid-Filled Sacs that can store water, food, salts, or pigments

Why are organelles evolutionarily advantageous?

Organelles allow for compartmentalization which allows for multiple reactions to occur at the same time. This ability is evolutionarily advantageous because it increases cellular efficiency.

Meiosis II

Prophase II consists of haploid cells that have sister chromatids
Metaphase II consists of the sister chromatids lining up on the metaphase II plate
Anaphase II consists of the sister chromatids separating from each other.
- > This is also where Mendels Law of Segregation is observed
Telophase II and Cytokinesis Haploid cell splits into two haploid cells

What are the three factors that result in genetic variation

Crossing over at the end of prophase I, Independent Assortment during Metaphase I, and Random Fertilization
- Honorable Mention = Anaphase II

Why is genetic variation among offspring an evolutionary advantage

Genetic Variation among offspring gives a higher chance for organisms of the population to survive if environmental conditions change. Therefore, it is evolutionarily advantageous to have offspring that vary genetically so that there is a higher chance the population survives

What are the 3 different life cycle types among sexually reproducing organisms?

Haplontic - Multicellular Haploid Stage is the most prominent and the diploid stage is the zygote which undergoes meiosis to form the haploid organism.

Diplontic - Multicellular Diploid Stage is the dominant life stage and haploid stage is present only in gametes formed by meiosis.

Haplodiplontic(Alternation of Generations) - Includes both dominant generations of diploid organisms (sporophytes) and haploid organisms (germatophyte)

What is the Genotype ratio of a monohybrid cross between 2 true-breeding individuals (one dominant and the other recessive)

100% Aa

True Breeding

An organism that is homozygous for an allele

What is the phenotypic and genotypic ratio of a monohybrid cross

Genotypic ratio: 1:2:1
Phenotypic ratio: 3:1

Genotype

The genes that underlie a physical trait

Phenotype

The expression of genotype

Mendels Law of Dominance

One allele is dominant over the other and will phenotypically mask its presence.

Mendels Law of Segregation

Alleles segregate into different gametes in Anaphase II of Meiosis II

Mendels law of Independent Assortment

Genes are separated into different gametes independent of one another
- The orientation of homologous chromosomes around the metaphase I plate is independent of other homologous chromosomes.

What are the two other important dominance patterns and their definitions?

Co-dominance
- Both alleles are dominant and are expressed
- Ex: If the blue and red alleles for a color gene are codominant, the flower will have spots of red AND blue all over it

Incomplete Dominance
- Neither allele is completely dominant, instead a blend of the two alleles are expressed
- White allele and red allele are incompletely dominant and produce a pink flowered phenotype for heterozygotes.

What is the most common misconception of evolution and why is it wrong?

The most common misconception is that evolution happens because populations want it to happen, or that its strictly helpful.
- This is wrong because evolution is completely due to random chance and it may even be harmful to a population. Evolution is based on the genetic variation in a population and therefore is not an intentional adaptation but an adaptation by chance.

What conditions must a population meet in order for it to evolve by natural selection?

The population must have: genetic variation, inheritable traits, and must live in an environment that cannot support the population.

What are the 5 different types of natural selection and describe them

Stabilizing Selection: Natural selection in which the neutral phenotype is selected for.

Directional Selection: One end of a spectrum of phenotypes are selected for (ex: animals on the white side of a black and white fur spectrum are selected for)

Disruptive Selection: Selection of the extremes of a phenotypic spectrum

Sexual Selection: Selection based on sexual fitness and preference for certain characteristics

Frequency-Dependent Selection: Selection based on the frequency of a phenotype
- Positive: The more frequent a phenotype is, the more fit it is.
- Negative: The less frequent a phenotype is, the more fit it is.

What are the 5 driving factors of evolution and describe

Genetic Drift: The random change in allele frequencies in a population over time
Gene Flow: The transfer of genes from one population to another
Mutation: Random mutations cause a populations allele frequencies to change
Non-Random Mating: Non-Random mating indicates some preference for certain characteristics in a population -> therefore leading to sexual selection
Natural Selection: Natural Selection is the selection of individuals based on the fitness of their phenotypes for the given environment.

What are the 2 different types of Genetic Drift and describe

Bottleneck Effect: When a random chance event kills off most of the population leaving a population of members that are not representative of the original population.

Founder Effect: When a small group, not representative of the original population, separates from the original population and settles in a new habitat. The allele frequencies here are different from the original which will lead to evolution.

What 5 conditions must be met for a population to be in Hardy-Weinberg Equilibrium

No Genetic Drift -> Large Population
No Gene Flow -> Isolated Population
No Random Mutations
No Natural Selection
Random Mating

What is Hardy-Weinberg Equilibrium

A state of a population in which it does not evolve and its allele frequencies do not change.

What are the Hardy Weinberg equations?

p + q = 1
p = frequency of dominant allele
q = frequency of recessive allele

p^2+2pq +q^2 = 1
p^2 = frequency of homozygous dominant genotype
2pq = frequency of heterozygotes
q^2 = frequency of homozygous recessive genotype

Genotype Frequency

Frequency of a certain genotype (specific gene composition) in a population
- Heterozygous genotypes are a separate frequency

Phenotype Frequency

Frequency of phenotypes in a population
- Heterozygotes are counted as part of the dominant phenotype frequency if the gene displays complete dominance.

What is an example of natural selection

Development of antibiotic resistance

What are the two types of speciation

Allopatric Speciation and Sympatric Speciation
- Allopatric speciation is speciation that occurs due to the geographical separation of a population of the certain species. Once separated, the two groups may develop distinct traits and evolve into new species.
- Sympatric Speciation is speciation that occurs in the same geographical area. Can occur due to conditions that make members of the same species unable to mate. -> Sexual Selection can cause this. Also nutrient separation in the same habitat can cause this.

What are the Prezygotic Barriers and explain them

Prezygotic Barriers are barriers that inhibit 2 species from mating in the first place.
1) Habitat Isolation: 2 species are separated geographically and therefore cannot mate
2) Gametic Isolation: The gametes of one species may not be recognized for fertilization
3) Mechanical Isolation: The location of reproductive organs on the 2 species make them unable to physically mate.
4) Temporal Isolation: The times of ovulation or fertility of the 2 species do not line up.
5) Behavioral Isolation: When a species does not respond to mating behaviors of other species.

What are the Post zygotic Barriers and explain them

Postzygotic barriers prevent a population of hybrid individuals from forming.
- Reduced Hybrid viability: Hybrid individuals die before birth
- Hybrid Sterility: Hybrids are sterile and cannot reproduce
- Hybrid Breakdown: While the first generation hybrids can breed with individuals of either parent species, the second generation hybrids are sterile.

How do the reproductive isolating mechanisms( pre and post zygotic barriers) support speciation.

A species by definition consists of individuals that cannot breed with other species, therefore, the reproductive isolating mechanisms ensure that a new species is formed by inhibiting mating with other species.

List the hierarchy of taxonomy from largest to smallest

Does King Phillip Come Over For Good Spaghetti
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Binomial Nomenclature

Way of naming species
(Name of Genus) (Name of species)

Ex: Polar Bears and Brown Bears are part of the same genus
- Polar bears: Ursus Maritimus
- Brown bears: Ursus Arctos

What are the main adaptations that plants developed for land, and how did each help?

Alternation of Generations
- Allowed plants to alternate between a sexually producing generation and an asexually reproducing generation in the case of harsh environments

Vasculature
- Allows plants to grow larger while still being able to effectively transport water and nutrients throughout their body.

Apical Meristems
- Allows plants to grow in their shoots and roots to access more resources-> growing towards the sun to access more light energy and growing in the soil to access more nutrient rich soil

Cuticle
- Prevents desiccation (water loss) which is extremely important for plants.

What are the 4 main groups of land plants?

Bryophytes
Seedless Vascular Plants
Gymnosperms
Angiosperms

Bryophytes

Nonvascular plants
- Seedless
- Gametophyte Dominant Life Cycle in which sporophyte grows and develops on the gametophyte completely.
- GAMETES released, not spores
- Consists of Mosses primarily
- Can be heterosporous or homosporous

Seedless Tracheophytes

Seedless Vascular Plants
- Sporophyte dominant Life Cycle in which the gametophyte is completely INDEPENDENT of the sporophyte
- Spores are released
- Gametophyte can grow independently of the sporophyte since the spore that is released from the sporophyte develops into the gametophyte.
- Can be heterosporous or homosporous

heterosporous

A term denoting that a plant produces 2 types of spores that develop into specific male or female gamtophytes
- BASICALLY: a plant that produces male or female spores.

Male spores are called Microspores
Female spores are called Megaspores

homosporous

A term denoting that a plant produces only one type of spore which develops into a hermaphrodite gametophyte, a gametophyte that has both male and female gametangia.

Sporangia

Structure in a a sporophyte in which the spores are developed

Megasporangia

Produce megaspores that develop into female gametophytes

Microsporangia

Produce microspores that develop into male gametophytes

Gametangia

Structure on a gametophyte in which gametes are produced, male or female.

Male gametangia -> Antheridia
Female gametangia -> Archegonium

Spermatophytes

Seed Vascular Plants
- Consist of Angiosperms and Gymnosperms
- Sporophyte dominant generation with dependent and reduced gametophyte
- Male gametophyte = pollen
- Seed = Zygote formed by fertilization of female gamete.
- Seeds are released as well as male gametophytes in the form of pollen
ALL are heterosporous

What are the 3 main types of plant cells

Parenchyma
- Thin walled plant cells
- Most common in plants
Collenchyma
- Thick but FLEXIBLE cell walls
Sclerenchyma
- Extremely thick RIGID cell walls packed with lignin that provide structure to plant
- Found dead at maturity

How do Monocots and Dicots differ in terms of roots, stems, and leaves

Roots:
- Monocots have fibrous dense roots
- Vascular structures are arranged in a ring around the pith
- Dicots have a tap root system
- Vascular structures are arranged in an alternating X pattern in the sclera

Stems:
- Monocots have the vascular bundles randomly scattered throughout the stem
- Dicots have their vascular bundles arranged in a ring formation around the central pith in the stem

Leaves:
- Monocots have linear venation in their leaves
- Dicots have highly branched venation in their leaves

What are the 3 types of permanent tissues in plants

Vascular Tissue
- Xylem and Phloem
Ground Tissue
- Parenchyma, Sclerenchyma, and Collenchyma Cells
- Cells that conduct photosynthesis, store materials, etc.
- Basically cells that aren't part of the xylem, phloem, or any of the dermal linings.
Dermal Tissue
- dermal linings of the plant structures and internal linings.

An area where leaves diverge off of a stem is called what?

A node

What are the 2 types of tissues in plants?

Meristematic Tissue and Permanent Tissue

What are the 3 types of Meristematic Tissues?

Apical Meristematic Tissue
- Found in root tips and shoot tips and allow the plant to grow up and down.

Lateral Meristematic Tissue
- Found in the stems or shoots of plants/woody trees that allow them to grow outwards/ become thicker.

Intercalary Meristematic Tissue
- Only found in Monocots and allows them to grow their leaves longer after they are cut (ex: grass)

What is the difference between Pollination and Fertilization?

Pollination is when the male gametophyte (pollen) lands on the stigma of a flower and builds the pollen tube to the female ovules.
- Basically the event of pollen traveling to another flower

Fertilization is the actual act of the male gametophyte producing 2 sperm cells that travel down the pollen tube and fertilize the eggs.

What are the main organ systems of plants?

Leaves, Stems and Roots

The area in a root where cells begin to differentiate into permanent tissue is called what?

Region of maturation

What are the 3 main tropisms of plants?

Phototropism, Gravitropism, and Thigmotropism

What are the characteristics of Bryophytes?

non-vascular, seedless, flagellated sperm, requires water to reproduce, Gametophyte dominant
- Moss

What are the characteristics of seedless tracheophytes

Seedless, have vasculature, release spores, sporophyte dominant with gametophyte INDEPENDENT, requires water to reproduce.
- Ferns

What are the characteristics of Gymnosperms

naked seeds that are not protected by ovary(fruit)
- Have vasculature, seeds, release seeds, sporophyte dominant with dependent and reduced gametophyte
- Also release pollen (male gametophytes)

A seed is a mature _________

Ovule
- The individual casings for the eggs inside the ovary

A fruit is a mature ______

Ovary
- Structure that contains all of the ovules in a flower.

What are the characteristics of angiosperms?

Flowering plants with seeds (ovules) that are encased by fruit (ovaries)
- Have vasculature, seeds, sporophyte dominant with reduced dependent gametophyte

Describe the Life Cycle of angiosperms

The sporophyte (heterosporous) produces a male and female spore. The male spore is housed in the anther of the sporangia where it develops into a gametophyte before it is released.

The gametophyte is composed of 2 cells, a pollen tube cell and a cell that becomes the 2 sperms during fertilization.

When the male gametophyte (pollen) is transferred (by water, wind, animals, explosions, etc.) onto the stigma of a flower, the pollen tube cell starts developing into the pollen tube reaching down the stigma through the style and attaching to an ovule in the ovary.
- This is pollination

Inside the ovule, the female spores are produced which then develop into female gametophytes. Each gametophyte produces 4 gametes but only 1 survives which's consists of an egg cell and a polar nuclei body and 6 other cells.

When the sperm reach the ovule, one sperm fertilizes the egg and the other fertilized the polar nuclear body developing into an endosperm that acts as a source of nutrition later on for the seed.
-> Fertilization

The zygote then develops into a seed in the ovary and when fully mature, the ovary develops into a fruit to protect the seed and acts as a vehicle for transportation for the seed.

How are fruits vehicles of transportation

Fruits can be carried by wind, animals, water, etc.

What is sporopollenin and why is it considered an evolutionary advantage

Sporopollenin is a material found in he casings of shells and pollen that is unnaturally resistant to chemical and biological changes, allowing seeds and pollen to survive HARSH conditions and still pollinate or germinate.

What is phototropism and how does it work?

Phototropism is the tendency for plants to grow in response to light

When sunlight hits a plant in an angle, the auxins in the plant move to the shaded side of the plant. When there are a lot of auxins on one side of a plant, they promote cell elongation, and therefore promote cell elongation on the shaded side of the plant.
This causes the plant to grow tawdry the light since the side facing the light is not elongating.

What is gravitropism and how does it work?

Plastids in the plant cell called amyloplasts react to gravity. When a plant is growing slanted, the amyloplasts settle in the bottom corner of the plant and induce cell elongation. Therefore the cells on the bottom portion of the slanted plant elongate faster therefore making the plant grow upright!

What is thigmotropism and how does it work?

When the stem makes contact with an object, the cells that make contact with the object slow their growth/elongation, making the stem wrap around the object.

Body Plans

Bilateral Symmetry
Radial Symmetry
Asymmetrical

What shape do aquatic animals usually have an why?

Fusiform Shape
The Fusiform shape allows aquatic organisms to limit drag on their body's from water.

What governs land animals adaptations?

Gravity

What is an exoskeleton

Hard outer covering (shell) that provides protection to organs, allows the attachment of muscles and only in land animals, prevents desiccation

What is the main limitation of an exoskeleton

Exoskeletons cannot grow with the organism and as such they need to be molted then replaced in order for animals to grow

Endotherm

An animal that maintains an internal body temperature through metabolic activity,

Exotherm

Animals that regulate their body temperatures by exchanging heat with their environment

What are the 4 types of animal tissues

Epithelial, Connective, Muscle, Nervous

What are the different cells that make up epithelial tissue

Squamous epithelial cells: Flat, thin, round cells
- Can be in a single thin layer (facilitate diffusion) or stratified (protect body from damage)

Cuboidal epithelial cells: uCbe shaped cells
- Secrtete glandular materials (often found in gland tissues)

Columnar epithelial cells
- Tall cells that are almost always in a single cell arrangement

Transitional Epithelial Cells
- Found in the bladder
- Stratified and stack on top of each other but can TRANSITION to be very thin layers in order to expand the volume of the bladder

What are the different Tissues are part of Connective Tissue

Adipose, Blood, Fibrous, Areolar, Bone, Cartilage Tissue

Adipose Tissue

Fat Tissue
Found in Subcutaneous fat tissue
Cells: Adipocytes (stores fat)

Blood Tissue

Liquid extracellular matrix: plasma
- Found in...blood
Cells: erthythrocytes (RBC) and leukocytes(WBC)

Fibrous Tissue

Tissue that binds structures together
- Found in the dermis, TENDONS and Ligaments
- Cells: Fibroblasts and Macrophages
- Fibers: Mostly Collagen

Loose/ Areolar Tissue

Binds skin together and to underlying organs and keeps organs in place
- Found in the dermis
- Most widespread
- Cells: Fibroblasts, Macrophages, neutrophils, and some lymphocytes
- Fibers: A little bit of all 3

Bone Tissue

Most rigid connective tissue, Internally supports body structures
- Found in the Skeleton
- Cells: Osteoblasts (make other osteo- cells), Osteocytes (regulate calcium deposition), and Osteoclasts (recycle osteocytes and bone tissue to make room for new bone- very active in bone repair)