Biology Final Review

Why are cells usually small?

The larger the cell, the more demands the cell places on its DNA & if the cell grows too large, it’ll have trouble moving nutrients and waste across the cell membrane.

What are the phases of Mitosis?

Prophase, Metaphase, Anaphase, Telophase and Cytokinesis.

What happens during Prophase?

Chromosomes coil and thicken and are now visible, spindle is formed, chromatids attach to spindle fibers.

What happens during Metaphase?

Centrioles at poles, chromatids at middle.

What happens during Anaphase?

Centromeres divided, chromatids pulled to opposite ends.

What happens during Telophase and Cytokinesis?

Nuclear membrane begins to form, cell pinches in (cleavage furrow), division of cytoplasm occurs.

What happens during the various stages of mitosis?

The cell prepares itself for division and divides.

Compare and Contrast Mitosis and Meiosis:

Mitosis - No genetic variation, produces two identical cells, maintains chromosome number (diploid), 1 division.

Meiosis - Promotes genetic variation, produces four unique gametes, halves chromosome number (haploid), 2 divisions.

How does Meiosis reduce the number of chromosome copies in the cell?

Through the separation of homologous chromosomes, diploid → haploid.

Why is it important that meiosis reduces the number of chromosome copies in the cell?

Cells need to maintain the right number of chromosomes for their offspring.

How does Meiosis promote genetic variation?

Through crossing over.

What is a karyotype?

A picture of an individual's chromosomes, arranged in pairs based on their size, shape, and banding patterns.

What is nondisjunction?

When a pair of homologous chromosomes fail to separate at anaphase, both chromosome pairs go to daughter cell.

What are some disorders that can result from errors of Meiosis?

Down Syndrome, Edwards syndrome, turner syndrome.

What was the work of Gregor Mendel?

Discovered 3 laws of genetics, forever changed biology, experimented with pea plants, discovered law of dominant and recessive alleles, principal of segregation, and principal of Independent assortment.

Why were Gregor Mendel’s experiments so successful?

Because all the traits were dominant and recessive and the traits were noticeable.

What is an Allele?

Any of the alternate forms of a gene that may occur at a specific locus, different versions of a gene.

What is the difference between dominant and recessive alleles?

Dominant alleles are represented by a capital letter, and are more likely to be passed on. Recessive alleles are represented by a lowercase letter and are less likely to be passed on.

What is the Law of Segregation?

Every individual carries two alleles for each trait which separate during the formation of egg and sperm cells.

What is the Law of Independent Assortment?

Inheritance of traits are determined by genes, genes passed down from parent to offspring, each gene has two+ forms called alleles, some alleles are dominant, some alleles are recessive.

What is Incomplete Dominance?

Phenotypes of parents appear to blend together in the phenotype of the offspring.

What is an example of Incomplete Dominance?

The red and white flowers creating pink flowers.

What is Codominance?

Neither allele is dominant or recessive, nor do alleles blend together in the phenotype of the offspring.

What is an example of Codominance?

White cows and brown cows creating a roan cow.

What are Multiple Alleles?

Three or more alleles for a trait.

What is an example of Multiple Alleles?

Blood types.

What are sex-linked traits?

Traits that are found on the X chromosomes.

Why do sex-linked traits typically affect males more often than females?

Males cannot be carries as the alleles can only go on X chromosomes, meaning if they have an allele for the trait they will have the gene.

What is a Pedigree?

A chart that shows our traits and how they are in our family.

Who was Charles Darwin?

Born February 12, 1809, “discovered” evolution.

Describe Charles Darwin’s voyage on the HMS beagle:

Much more different than his life back in England, visited many different islands and studied biology/biodiversity.

Compare Natural Selection and Artificial Selection:

Natural Selection happens when an organism survives because they are better suited for their environment, while artificial selection is at the hands of humans and traits are artificially chosen.

What is an Adaption?

Characteristics of organisms that enhance their survival and reproduction in specific environments.

Give an example of an Adaption:

Humans no longer needing wisdom teeth because we no longer eat sticks or tough meats.

What are Homologous Structures?

Features that are similar I structure but have different functions.

What is an example of Homologous Structures?

An arm of a human and animal (bat, dolphin).

What are Analogous Structures?

Structures that perform a similar functions but not similar in origin.

What is an example of an analogous structure?

Wings of birds, insects, and bats.

What is a Vestigial Structure?

A structure/organ that is no longer function because of adaption.

How do Vestigial Structures provide evidence for evolution?

It shows how we adapted out of an organ’s usage.

What are the three types of selection?

Directional, stabilizing, and disruptive.

What is Directional selection?

Favors phenotypes at one extreme of a traits range.

What is Stabilizing selection?

Intermediate phenotype is favored (middle).

What is Disruptive selection?

Both extreme phenotypes are favored.

What is a Gene Pool?

The combined alleles of all of the individuals in a population.

What is Allele Frequency?

A measure of how common a certain allele is in the population.

What is Microevolution?

The observable change in the allele frequencies of a population over time.

What is Genetic Drift?

Changes in allele frequencies that are due to chance, causes a loss of genetic diversity.

What is the Hardy Weinberg Equilibrium?

The allele frequencies in a population tend to remain the same from one generation to then ext unless acted on by outside forces.

What are the five conditions necessary for a population to be in the Hardy-Weinberg Equilibrium?

Large population, no migration, no mutation, random mating, no natural selection.

What are the levels of hierarchy used in biological classification?

Kingdom → Phylum → Class → Order → Family → Genus → Species

What are the three domains?

Archaea, Bacteria, Eukarya.

What are the main characteristics of Archaea?

Unique cell membrane, prokaryotic, found in extreme conditions.

What are the main characterstics of Bacteria?

No nucleus, unicellular, prokaryotic.

What are the main characteristics of Eukarya?

Eukaryotic, membrane bound organelles.

What are the six kingdoms of life?

Archaea, Bacteria, Protista, Fungi, Plantae, Animalia.

What are the four principles of natural selection?

Variation, inheritance, selection and overproduction.

What are the two main sources of genetic variation?

Mutation and recombination.

What are two types of genetic drift?

Bottleneck and founder Effect.

What is the Bottleneck Effect?

A dramatic loss in a population’s genetic diversity due to a drop in population size.

What is the Founder Effect?

A population is established by a small group from a larger and more diverse population.

What are the main characteristics of the Archaea kingdom?

Unicellular, prokaryotic, microorganisms.

What are the main characteristics of the Bacteria kingdom?

Unicellular, prokaryotic, no membrane-bound nucleus, asexually reproduce

What are the main characteristics of the Protista kingdom?

Eukaryotic, uni/multicellular, asexual and sexual reproduction

What are the main characteristics of the Fungi kingdom?

Heterotrophic, reproduces through spores.

What are the main characteristics of the Plantae kingdom?

Multicellular, eukaryotic, autotrophic.

What are the main characteristics of the Animalia kingdom?

Multicellular, eukaryotic, heterotrophic.

What happens during G1 phase?

The cell increases in size,increase organelles size.

What happens during Synthesis phase?

Replication of DNA

What happens during G2 phase?

Cell assembles special structures for mitosis.

What is the acronym for the order of classification?

King Philip Came Over For Grape Spaghetti.

What is one limitation of the classification system?

It is based on physical characteristics.

How many kingdoms are there?

6.