bio study guide fall 2025

What are the components of organ systems? Select all that apply. 

Organs, Tissues, Cells

Which of the following is defined as a community interacting with its environment? 

Ecosystem

Which of these are cellular activities that sustain a single-celled organism through its lifetime? Select all that apply. 

Increases in cell size and volume, The transmission of DNA to offspring processes by which individuals produce offspring

Which of these organisms is an example of a producer?

 A plant that gathers energy from sunlight to make its own food

What is the process in which organisms keep their internal conditions within tolerable ranges by sensing and responding appropriately to change? 

Homeostasis

Which of the following are the steps of the scientific method? Select all that apply. 

Observe some aspect of nature, Make a hypothesis ,Report your work to the scientific community, Test the hypothesis, Form a conclusion

What is a control group?

A group of individuals identical to an experimental group except for the variable under investigation

Which process describes the ability of living organisms to maintain an internal environment within a tolerable range?

homeostasis

Which of the following defines the first law of thermodynamics?

 Energy cannot be created or destroyed

In the following chemical reaction, which compounds are the products?

Carbon dioxide + Water → Sugar + Oxygen

Sugar and oxygen

What are the features of an energy-requiring reaction? Select all that apply.

The reaction requires an input of energy.

The energy captured by producers and stored in chemical bonds is eventually lost from the ecosystem in a one-way ____ . In contrast, nutrients are continuously ____

 in trophic interactions between producers and consumers.

Flow and recycled

Which of the following best describes a decomposer? 

An organism that feeds on biological remains and breaks down organic material into its inorganic subunits

Which of the following best describes the greenhouse effect?

 A warming of Earth’s lower atmosphere and surface as a result of heat trapped by greenhouse gases

Which of the following processes of the carbon cycle involves the incorporation of carbon in the shells of marine organisms into the Earth’s crust?

Sedimentation

Which of the following is a process of the nitrogen cycle that involves the conversion of nitrogen gas to ammonia?

 Nitrogen fixation

The phosphorus cycle is an example of a _______, a biochemical cycle in which the atmosphere plays little role and rocks are the major reservoir. In comparison, _________ are biogeochemical cycles in which a gaseous form of an element plays a significant role.

sedimentary cycle,  atmospheric cycles

Which of the following organisms capture energy and use it to make their own food from nonbiological materials in the environment?

Producers

Which of the following is an action that decreases the amount of available phosphates stored in soil, lakes, or rivers?

The uptake of phosphates by producers

Which of the following compounds of the nitrogen cycle is the main source of bioavailable nitrogen for plants?

 Ammonium

Which of the following stages of the carbon cycle contributes the most to the rise in atmospheric levels and global climate change?

The burning of fossil fuels

Which of the following defines the atomic number of a given element?

The number of protons in the atomic nucleus

Which of the following is described as a pure substance that consists only of atoms with the same number of protons?

Element

Which of the following levels in the shell model of an atom can hold up to two electrons?

The first shell

Which of the following polysaccharides is the principal form of stored sugars in animals?

Glycogen

In proteins, which of the following are the characteristic patterns that arise when hydrogen bonds form between amino acids?

Secondary structure

Which of the following is defined as the loss of a protein’s three-dimensional shape and function?

Denaturation

Fatty acids and nucleotides are examples of molecular subunits called ______

 . Complex molecules such as proteins or nucleic acids formed from these repeated molecular subunits are called ______

 .

monumers, polymores

Which of the following describes a lipid?

A fatty, oily, or waxy organic compound often composed of fatty acids

Which of the following describes an organic molecule that consists of one or more chains of amino acids folded up in a specific shape?

Protein (muscle) 

What is the distribution of individuals among various age groups in a population?

Age structure

Which of the following are variables in the direct calculation of per capita growth rate? Select all that apply.

Initial population size

Per capita birth rate

Per capita death rate

What are the assumptions of the exponential model of population growth? Select all that apply.

Constant per capita growth rate

Unlimited resources

Which of the following defines the carrying capacity of a population?

The maximum number of individuals of a species that a specific environment can sustain

Which of the following are examples of density-independent limiting factors? Select all that apply.

A tsunami wipes out most individuals of a tidal ecosystem.

An extreme drought negatively impacts a population of plants.

Which of the following defines the biotic potential of a species?

Maximum possible population growth under optimal conditions

What are trends that promoted large increases in the human population? Select all that apply.

Humans sidestepped some limiting factors that typically restrain population growth.

Humans developed technologies that increased the carrying capacity of existing habitats.

Humans migrated into new habitats and expanded into new climate zones.

What is the average number of children born to females of a population over the course of their lifetimes?

Total fertility rate

What defines the postindustrial stage of the demographic transition model?

A population's growth rate becomes negative and the population size slowly decreases.

What advancements in human history led to large decreases in the death rates of human populations? Select all that apply.

Improved understanding of the link between certain microbes and human diseases

Improved sanitation of living environments and medical practices

The development of vaccines and antibiotics

What features are a part of all cells? Select all that apply.

Plasma membrane

Cytosol

DNA

Ribosomes

What are the tenets of cell theory? Select all that apply.

Every living organism consists of one or more cells.

Cells are individually alive and are the basic structural and functional units of life.

All living cells arise by division of preexisting cells.

What kind of membrane proteins trigger a change in cellular activity in response to a stimulus?

Receptor proteins

Which of these structures is not an example of an extracellular matrix?

Nuclear envelope

What features of mitochondria are similar to bacteria? Select all that apply.

Membrane-bound ribosomes

Independent movement

Circular DNA similar to plasmids

Which phase of interphase is characterized by a period of cell growth and the production of molecules for DNA replication?

G1

Which of the following is a stage of mitosis? Select all that apply.

Anaphase

Prophase

Metaphase

Telophase

_________ is a nuclear division mechanism that maintains the ____________.

Mitosis, chromosome number.

During which stage of mitosis are the chromosomes aligned midway between the spindle poles?

Metaphase

What occurs during the prophase stage of mitosis?

Chromosomes pack tightly and become attached to a newly forming spindle

Which of the following demonstrates the link between oncogenes and cancer?

The mutations in oncogenes increase the activity or number of molecules that stimulate mitosis, leading to irregular cell division.

Which of the following are characteristics of benign tumors? Select all that apply.

They stay in their home tissue.

Which of the following is NOT an example of fail-safe mechanisms that prevent the irregular cell divisions characteristic of cancer?

Mutation in a tumor suppressor gene

In which stage of mitosis do the chromosomes reach opposite sides of the cells and a new nuclear envelope forms around each cluster of chromosomes?

Telophase

What occurs during the anaphase stage of mitosis?

Sister chromatids separate and move toward opposite spindle poles.

Which of the following defines a telomere?

A region of noncoding DNA at the end of a chromosome that protects coding sequences from degradation

Which of the following defines a genotype?

The particular set of alleles that is carried in an individual’s chromosomes

An individual with the same allele of a gene on both homologous chromosomes is ___________. for allele. An individual with different allele genes is a _________ for the allele.

homozygous, heterozygote

Which of the following genotypes is indicative of an individual who is homozygous for a recessive allele?

pp

If an individual is homozygous dominant for a given allele (AA), what allele will be carried by that individual’s gametes?

A

Which of the following defines polygenic inheritance?

A pattern of inheritance in which multiple genes affect one trait

Which of the following is an example of environmental impacts on the expression of traits?

Animal coat color shifts in response to seasonal changes in day length and temperature.

Which of the following is defined as an individual’s observable traits?

Phenotype

If one parent is heterozygous for an autosomal allele (Aa), and the other is homozygous for the recessive allele (aa), what is the probability that their child will inherit the dominant allele and have the associated trait?

50 percent

If both parents are heterozygous for an autosomal trait (Aa), what is the probability that their child will inherit two recessive alleles and have the associated trait?

25 percent

For an X-linked recessive allele, what proportion of female offspring will be carriers in the cross of an affected father and a noncarrying mother?

100 percent

Which of the following disorders in humans has an X-linked recessive inheritance pattern?

Red-green color blindness

Which genotype indicates a carrier of an autosomal recessive trait?

Bb

In a pedigree, the relationships between individual family members are represented as _________. Individuals who have the studied trait are represented by

lines, filled shapes.

Which of the following statements about X-linked recessive patterns is true?

An affected father can never pass an X-linked recessive allele to an XY son.

Which of the following is the definition of a gene?

A unit of information encoded in the sequence of nucleotide bases in DNA

In gene expression, a gene is _______ into mRNA, which is then ________ into a protein.

transcribed, translated

Which of the following is the function of transfer RNA?

Delivers amino acids to ribosomes

________are three-nucleotide units of information in mRNA that often specify a particular amino acid. They correspond to complementary sets of three nucleotides on tRNA called _______

Codons , anticodons

Which of the following codons is called the start codon?

AUG

Where does the transcription of DNA into mRNA occur in eukaryotes?

Nucleus

Which of the following amino acids is carried by the tRNA that initiates translation in eukaryotes?

Methionine

Which of the following mutations is most likely to cause a single amino acid difference during the translation of mRNA into protein?

Base-pair substitution

Which of the following nitrogenous bases is found in RNA but not in DNA?

Uracil

Which of the following mutations involve the loss of one or more nucleotides from a gene sequence?

Deletion

Which of these observations about genetics influenced the principles of natural selection? Select all that apply.

Different forms of genes, alleles, give rise to variation in shared traits.

Shared traits in populations are heritable in the form of genes.

Which of these factors influence the radioactive decay measured by radiometric dating?

Half-life

What are homologous structures?

Body structures that are similar in different lineages because they are derived from a feature present in a common ancestor

What is a form of a heritable trait that enhances an individual's fitness?

Adaptation

What is a mode of natural selection that favors a phenotype at one end of a range of variation?

Directional selection

What is the gene pool?

All of the alleles of all the genes in a population

Which of these scenarios is an example of disruptive selection?

The dark and light color morphs of a butterfly population are maintained, and the intermediate gray morph has been eliminated from the population.

Which of these interactions are examples of sexual selection? Select all that apply.

Male seals compete for territory and access to clusters of female seals. The more aggressive male seals tend to secure the largest territories and clusters.

Female flies prefer to mate with males that have longer eyestalks. These eyestalks provide no survival advantage, but longer eyestalks become more common over generations.

What can result when a small group of related individuals forms a new, isolated population? Select all that apply.

Founder effect

Inbreeding

Bottleneck

What is known as a collection of one or more specific cell types that are organized in a way that suits them to a task?

Tissue

What is the function of the endocrine system?

To secrete hormones that control the activity of other organ systems

Which human organ system returns tissue fluid to the blood and defends the body against infection?

Lymphatic system

Epithelial cells are specialized for four of the five following functions. Select the exception.

contraction

Endocrine glands secrete ____.

hormones

Embryonic cells that have the potential to become any cell type are called ____ cells.

pluripotent stem

Maintaining the volume and composition of blood is the direct responsibility of which system?

urinary

Which of the following compounds are products of aerobic respiration? Select all that apply.

Carbon dioxide

Water

______________ is the main respiratory protein of vertebrates and some invertebrates such as earthworms. 

Hemoglobin

_______ is a copper-containing respiratory protein in invertebrates such as octopuses and horseshoe crabs.

Hemocyanin

Which of the following is an internal respiratory organ in which blood exchanges gases with the air?

Lung