Semester 2 Final- Bio

The process of cell division in which the nucleus divides into two identical nuclei.

Mitosis Phase

The division of the cytoplasm to form two separate daughter cells.

Cytokinesis Phase

End Result of Cell Division

The production of two genetically identical daughter cells, each maintaining the same number of DNA.

Importance of the Cell Cycle

Critical for growth and development by enabling cell replication and specialization.

Purpose of DNA Replication

To ensure the accurate transmission of genetic information during cell division.

Process of DNA Replication

Includes unzipping of DNA, attachment of free nucleotides to complementary base pairs, and synthesis of new DNA strands using DNA polymerase.

DNA Replication - Semiconservative

The process in which each DNA molecule has one strand from the original DNA and one newly formed strand, using templates and complementary base pairing.

A molecule of DNA that is tightly coiled around proteins and contains many genes.

Chromosome

Two identical pieces of DNA from DNA replication, visible as the cell prepares to divide, resembling an 'X'.

Replicated Chromosome

A single piece of DNA, visible as the cell prepares to divide, resembling an 'I'.

Unreplicated Chromosome

Cell Cycle

The series of events that take place in a cell leading to its division and duplication to produce more cells. It consists of interphase, mitosis, and cytokinesis.

The phase in the cell cycle when the cell grows, carries out its normal functions, and prepares for cell division. It includes G1, S, and G2 phases.

Interphase

The process of cell division used by body cells for growth and repair, in which a parent cell divides into two genetically identical daughter cells, each containing the same number of chromosomes as the parent cell.

Mitosis

The final stage of cell division, during which the cytoplasm is divided and two daughter cells are formed.

Cytokinesis

G1 Phase

The first phase of interphase, during which the cell grows and carries out its routine functions.

S Phase

The phase of interphase when the cell's DNA is replicated, ensuring that each daughter cell receives an identical copy of the genetic material.

G2 Phase

The phase of interphase when the cell prepares for mitosis by synthesizing proteins, duplicating organelles and the cell checks over the replicated DNA for any mutations and prepares for cell division.

Prophase

The first stage of mitosis, characterized by the condensation of chromatin into chromosomes and the appearance of spindle fibers.

Metaphase

The stage of mitosis during which the replicated chromosomes align along the cell's equator, ready to be separated into the daughter cells.

Anaphase

The stage of mitosis when the sister chromatids are pulled apart by the spindle fibers and move towards opposite poles of the cell.

Telophase

The final stage of mitosis, during which the chromosomes arrive at the poles of the cell, the nuclear envelope reforms, and the chromosomes begin to uncoil.

A group of diseases characterized by uncontrolled cell growth and division, often caused by genetic mutations.

Cancer

The process of producing two identical replicas of DNA from one original DNA molecule, ensuring accurate transmission of genetic information during cell division.

DNA Replication

The mechanism by which DNA is replicated, where each new DNA molecule consists of one original strand and one newly synthesized strand.

Semiconservative DNA Replication

An enzyme responsible for unwinding the DNA double helix during DNA replication by breaking the hydrogen bonds between complementary base pairs.

DNA Helicase

An enzyme that synthesizes new DNA strands by adding nucleotides to the growing DNA molecule during DNA replication.

DNA Polymerase

One of the two identical copies of a replicated chromosome, joined at the centromere, which are separated during cell division.

Sister Chromatid

The region of a chromosome to which the microtubules of the spindle attach during cell division.

Centromere

The different forms of a gene (two versions: dominant & recessive)

Allele

An allele whose trait ALWAYS shows up in the organism when the allele is present

Dominant Allele

An allele that is masked/hidden when a dominant allele is present

Recessive Allele

Having two identical alleles for a trait

Homozygous

Having two different alleles for a trait

Heterozygous

Genotype

An organisms genetic makeup, or allele combinations

Phenotype

The physical traits that appear in an individual as a result of its genotype

Genes that reside ONLY on the X chromosome; more commonly found in males.

Sex-linked Traits

Passing of traits from parent to offspring

Heredity

Section of DNA that codes for a protein

Gene

Image that depicts the total number (and pairs) of chromosomes from a dividing cell

Kayotype

Pairs of chromosomes: same size, contain same type of genes, NOT identical to each other. Inherited from each parent.

Homologous Pairs

Chromosomes that carry genes which determine the traits of an individual.

Autosomes

Sex Chromosomes

Pair of chromosomes that determine the biological sex of an individual.

Biological Female

XX

Biological Male

XY

Define genetic variation

The diversity of alleles and genotypes within a population or species

What is VEAR?

Variation, Environment, Adaptation, and Reproduction, which are key components of natural selection.

Define environment

Place where the population olives (includes trophic and non-trophic relationships)

How might the environment cause species to evolve?

The environment presents different challenges and possibilities that allow a species to adapt.

Canada geese have a large population size, and many populations are interconnected because geese can fly between different locations-will the population adapt or go extinct?

Adapt

Ladybugs have a lot of genetic variation within their populations-will the population adapt or go extinct?

Adapt

Sea otters have very low levels of genetic variation because humans hunted them for their fur in the 1800s-will the population adapt or go extinct?

At risk of extinction due to low genetic variation.

Hibiscus plants need bright sunlight to survive. Imagine that a volcano erupts in the plants' environment. The eruption rapidly changes the environment by creating clouds of ash and smoke that block out the sun for a long time-will the population adapt or go extinct?

At risk of extinction due to environmental change.

What is a mutation?

A change in the DNA sequence of an organism.

What is an example of a mutation as an evolutionary force that can change the genetic variation in a population?

Mutations create new alleles

Do mutations increase or decrease variation? Why?

Increase genetic variation because they introduce new alleles into the gene pool due to random changes in DNA sequences and chromosome structure creating genetic differences.

What is non-random mating?

Mates are not chosen by chance. Some individuals have a higher/lower chance of reproducing.

Does non-random mating increase or decrease variation? Why?

Can decrease variation disadvantageous traits may become very uncommon.

What is the bottleneck effect?

Population shrinks suddenly

Does the bottleneck effect increase or decrease variation? Why?

Decreases variation because it reduces the number of alleles in the gene pool.

What is migration?

Individuals move between populations.

Does migration increase or decrease variation? Why?

Increases genetic variation by introducing new alleles into populations and reducing genetic differences between populations.

What are the 3 types of natural selection?

Directional, stabilizing, and disruptive selection

What is directional selection?

One extreme phenotype is more fit than all the other phenotypes.

What is stabilizing selection?

Intermediate phenotypes are more fit than extreme ones.

What is disruptive selection?

Both extreme phenotypes are more fit than those in the middle.

What is speciation?

When one species diverges (splits) into 2 DIFFERENT species (their DNA cannot be identical once they diverge)

Which type of selections could lead to scientists classifying different populations of organisms as 2 different species?

Directional and disruptive selection

What are the mechanisms for speciation?

Geographical and reproductive isolation

What is geographical isolation?

Physical separation of members of the same species.

What is reproductive isolation?

Various mechanisms that prevent species from producing fertile offspring.

What is divergent evolution?

The process by which closely related species evolve different traits or characteristics due to adapting to similar environments.

What is convergent evolution?

The process by which unrelated species evolve similar traits or characteristics due to adapting to different environments.

What are types of evidence for evolution?

Fossils, vestigial structures, homologous structures, analogous structures, embryology, biochemical similarities

What are fossils?

Preserved remains or traces of ancient organisms.

What do fossils show us?

Species have become extinct and new species have formed.

What are vestigial structures?

Have no function, but had a function in the species' ancestors. Anatomical features that have lost their original function in the course of evolution.

What are homologous structures?

Structures that have similar anatomy because they evolved from a common ancestor (may have different functions)

What are analogous structures?

Have similar functions but different anatomy because they evolved through convergent evolution (NOT from a common ancestor)

What is an embryo?

A young plant/animal in early stages of development.

What are biochemical similarities?

Similarities in amino acids indicate similar DNA. Very solid evidence in common ancestry.

What are adaptations?

Genetic traits that help an organism to survive or reproduce in its environment.

What is a gene pool?

All of the alleles within a population-each individual has 2 alleles for every gene.

Define species

A group of individuals that actually or potentially interbreed in nature.

What is taxonomy?

A system of grouping organisms according to their morphological (physical) characteristics/traits.

What are the 8 Taxa Levels?

Domain, kingdom, phylum, class, order, family, genus, species

What is Binomial Nomenclature?

2 word naming system-gives each species a scientific name.

What are Cladistics?

A system of grouping organisms based on evolutionary descent.

What evidence do scientists use when classifying organisms?

Morphology (body structure), behavior, molecular (DNA), fossils

What do Nodes represent on a Cladogram?

Represent split into 2 groups

What do Point of Split represent on a Cladogram?

Common ancestor of all groups beyond that point.

How do you determine if 2 species are more closely related?

They share a more recent common ancestor.

What is a common ancestor?

A species in the past from which new species have evolved.

Theory

The best explanation of an aspect of the natural world, supported by evidence. But is subject to change!

Process by which modern organisms have descended from ancient organisms (decent with modification)

Evolution

formation of new species as a result of geographic or reproductive isolation.

Speciation

Similar structures (ie bone arrangement) but different functions/purpose as a result of divergent evolution; evidence of common ancestry

Homologous structures

Similar function/purpose but different structures as a result of convergent evolution. Organisms have DIFFERENT ancestral origins.

Analogous structures

Earliest stages of development are similar across species; indicates common ancestry

Embryology

process by which a single species or small group of species evolves into several different forms that live in different ways

Divergent evolution

process by which unrelated organisms independently evolve similarities when adapting to similar environments

Convergent evolution