Conceptual Biology Review

Flashcards for reviewing key concepts in conceptual biology, covering topics from genetics to ecology.

What is a population in biological terms?

Organisms of the same species that can mate with each other in the same location.

What is a gene pool?

All of the alleles (genes) in a population.

What is microevolution?

Any change in the percentage of the dominant or recessive alleles (called allelic frequency) in a gene pool over time.

What is genetic drift?

Random events that cause random deaths in a population, leading to a change in allele percentage and micro-evolution.

How does genetic drift impact small populations?

Small populations evolve more dramatically from generation to generation than large populations.

What is gene flow?

The process where organisms migrate to different populations, carrying their alleles with them, leading to evolution.

What are selecting factors in natural selection?

Anything in nature that can kill and change the genetic makeup of a gene pool.

What is an adaptation?

An inherited trait controlled by DNA that gives an organism an advantage at living.

Define 'fittest' in the context of natural selection.

Organisms that live despite selecting factors.

What are the four parts of natural selection?

Overproduction, genetic variation, struggle to survive, and differential reproduction.

What is the study of genetics?

The study of how traits are passed from one generation to the next.

Where are genes found?

Genes are found on homologous chromosomes, with two genes for every trait.

What are alleles?

Alleles are genes that code for one specific trait, found on each homologous chromosome.

How many alleles do diploid organisms have?

Diploid organisms have one allele on each homologous chromosome (one allele from mother, one allele from father).

When are dominant alleles expressed?

Dominant alleles are expressed whenever they are present in an organism.

When are recessive alleles expressed?

Recessive alleles are expressed ONLY IN THE ABSENCE of the dominant allele.

What is a genotype?

The genetic makeup (2 alleles) of an organism for a characteristic.

What is a phenotype?

The how the organism physically appears.

What does it mean for an organism to be homozygous?

Homozygous organisms have two of the same allele (TT or tt).

What does it mean for an organism to be heterozygous?

Heterozygous organisms have one dominant and one recessive allele (Tt).

What is a Punnett Square?

A diagram that predicts the expected outcome of the offspring.

What does a genotypic ratio show?

The number of organisms with each genotype is listed with colons between them (e.g., 1RR:2Rr:1rr).

What does a phenotypic ratio show?

The number of organisms with each phenotype is listed with colons between them (e.g., 3 Purple: 1 White).

Describe dominant/recessive inheritance.

Dominant allele masks recessive allele. Tt = Tall.

Describe incomplete dominance.

Two alleles mix together, for instance Rr = Pink flowers.

Describe co-dominance.

Two alleles are both expressed, for instance BW = Black and white feathers.

What are the two parts of cell development?

Interphase (majority of the cell’s life) and Division: Mitosis and Cytokinesis

What happens in G1 phase of interphase?

Cell grows and does its job in the body, with DNA used to make proteins needed for the cell to do its job.

What happens in S phase of interphase?

DNA synthesis/replication, making two identical copies of DNA.

What happens in G2 phase of interphase?

Cell prepares for cell division, and DNA is used to make proteins needed for cell division.

What happens during prophase?

DNA winds (shortens) into chromosomes, the nucleus falls apart, and spindle fibers form.

What happens during metaphase?

Chromosomes line up in the middle of the cell, and spindle fibers connect sister chromatids to centrosomes.

What happens during anaphase?

Sister chromatids pull apart and move to opposite ends of the cell.

What happens during telophase?

Sister chromatids (chromosomes) unwind, the nucleus reforms, and spindle fibers fall apart.

What is the role of RNA in protein synthesis?

RNA makes proteins using the DNA code; this process is the same for all life.

What is the role of mRNA?

Carries copy of gene to ribosome.

What is the role of rRNA?

Holds mRNA during translation.

What is the role of tRNA?

Identifies codons and brings amino acids to correct codon.

What happens during transcription?

DNA writes a letter (RNA) and sends it to the ribosome mailbox.

Where does transcription occur?

Transcription occurs in the nucleus.

During transcription, what pairs with Guanine?

Cytosine.

During transcription, what pairs with Cytosine?

Guanine.

During transcription, what pairs with Thymine?

Adenine.

During transcription, what pairs with Adenine?

Uracil.

What happens during translation?

Ribosome receives the letter (mRNA) and tRNA reads it.

Where does translation occur?

Takes place at the ribosome on the endoplasmic reticulum in the cytoplasm.

What is the start codon in translation?

AUG.

What is the final destination of a protein and what happens?

Vesicle arrives in location where a chemical reaction needs to happen.

What are the three parts of a nucleotide?

Phosphate group, Sugar, and Nitrogen base.

What are the nitrogen bases in DNA?

Guanine, Adenine, Cytosine, and Thymine.

Which nitrogen bases pair together?

Guanine pairs with cytosine and Adenine pairs with thymine.

What is semi-conservative replication?

Both new DNA molecules are half original/half new.

What is population growth rate determined by?

Birth rate and mortality rate.

What factors determine carrying capacity?

Limiting factors such as predation, competition, and habitat space.

How do predator and prey populations affect each other?

When prey population is high, predator population increases, and vice versa.

What has allowed human population to grow exponentially?

Agricultural revolution, better sanitation, better health care, better food supply, and better technology.

What is biodiversity?

The number of different species in a community.

What is competition in ecology?

Two organisms that have the same or similar niche (job).

What is a niche?

Everything that an organism does and uses in an ecosystem.

What are non-native species?

Visiting species brought to a new place by humans that have an unfair advantage over native species.

Define predator/prey relationship.

One organism (predator) kills and consumes the other organism (prey) for energy.

What is symbiosis?

Two different species rely on each other for survival.

What is mutualism?

A partnership where both organisms benefit.

What is parasitism?

A partnership where one organism benefits (the parasite) and the other is harmed but not killed (the host).

What is commensalism?

A partnership where one organism benefits and another is not harmed or benefits in any way.

What is a food web?

Shows many ways energy moves in an ecosystem.

What is a food chain?

Shows one way that energy moves through an ecosystem.

What is a trophic level?

Each organism in the food chain represents a trophic level.

What is an energy pyramid?

Shows the change in population for one food chain.

Approximately how much energy is transferred from one trophic level to the next?

10%.

What are biogeochemicals?

Chemicals found in nonliving and living parts of nature that always cycle.

What are reservoirs?

Places in an ecosystem where biogeochemicals are commonly found.

Importance of Water

Allows things to move throughout the body

Importance of Carbon

The main atom that is the building block of molecules found in life

Importance of Nitrogen

Needed for protein and DNA

What are the levels of ecology?

Biosphere, Ecosystem, Community, Population, Organism.

Define Biosphere

Surface of Earth and oceans which support life.

Define Ecosystem

Studies all living and nonliving factors in an environment

Define Community

Studies only living organisms in a place

Define Population

Studies one species (type) of organism

Define Organism

An individual life