hesi bio prep

The light reaction of photosynthesis occurs in the

A. Nucleus
B. Ribosomes
C. Thylakoid membranes
D. Stroma

Thylakoid membranes

All of the following are involved in the regulation of blood glucose concentration EXCEPT:

A. HGH (Human growth hormone)
B. The liver
C. Insulin
D. Glucagon

HGH

Which enzyme breaks down starch to disaccharides?

A. Gastrin
B. Secretin
C. Maltase
D. Amylase

Amylase

Which of the following statements about enzymes is NOT true?

A. Enzymes optimally operate at a particular pH
B. Enzymes are almost always proteins
C. Enzymes optimally operate at a particular temperature
D. The activity of enzymes is unaffected by genetic mutation

The activity of enzymes is unaffected by genetic mutation

Pancreatic lipase is involved in the digestion of

A. Protein
B. Cellulose
C. Starch
D. Fat

Fat

A mechanism that mammals have developed to dissipate excess heat in hot weather is

A. Sweating
B. Huddling
C. Burrowing
D. Sitting in the shade

Sweating

Which structure is found in protists but not in monerans?

A. Cytoplasm
B. Cell membrane
C. Chromosome
D. Golgi apparatus

Golgi apparatus

Monerans are prokaryotic, and they do not have vacuoles, centrioles, mitochondria, lysosomes, endoplasmic reticula, nuclear membranes, or Golgi apparatuses

Body temperature can be increased by all of the following EXCEPT

A. Drinking alcohol, which results in vasodilation
B. Reducing blood flow to ears
C. Muscle contractions
D. Increasing metabolic activity

Drinking alcohol, which results in vasodilation

It is a myth that alcohol warms the body

Water diffuses into and out of cells via

A. Active transport
B. Osmosis
C. Carrier proteins
D. Symport systems

Osmosis

In which of the following areas of the brain do speech, conscious thinking, and control of skeletal muscles occur?

A. Optic chiasma
B. Corpus caollosum
C. Cerebellum
D. Cerebral cortex

Cerebral cortex

Speech, conscious thinking, and control of skeletal muscles occur in the cerebral cortex. This is the thin outer layer of cerebrum.

Which one is not a reactant in photosynthesis?

A. Glucose
B. Water
C. Carbon dioxide
D. Light energy

Glucose

The reactants in photosynthesis are water, light energy, CO2, and chlorophyll. The products are glucose, O2, and water.

Which of the following statements about genes is NOT true?

A. Genes consist of DNA
B. Genes may contain the instructions for proteins
C. Genes may be transcribed into messenger RNA
D. Genes are copied during translation

Genes are copied during translation

Genes are made of DNA and are arranged into long strands known as chromosomes. DNA may be transcribed into messenger RNA, which is used to make proteins during the process known as translation. Genes thus contain the instructions for protein. Copying genes occurs during REPLICATION, not translation; replication occurs during mitosis and meiosis

Which of the following would normally contain blood with the least amount of oxygen?

A. The left atrium
B. The pulmonary arteries
C. The left ventricle
D. The pulmonary veins

The pulmonary arteries

The pulmonary arteries carry deoxygenated blood from the heart to the lungs, where it is oxygenated for transport back to the heart and throughout the body

Spindles finish elongating in which phase of mitosis?

A. Metaphase
B. Telophase
C. Prophase
D. Anaphase

Metaphase

During metaphase, the spindles finish elongating, and the chromosomes attach themselves along the length of the spindle apparatus

All of the following products form as a result of a condensation or dehydration reaction EXCEPT

A. Steroids
B. Proteins
C. Triglycerides
D. Disaccharides

Steroids

A dehydration reaction occurs when the loss of a water molecule follows the bonding of two monomers. Such loss of water molecules follows the joining of two amino acids in the formation of a protein, two monosaccharides in the formation of a disaccharide or polysaccharide, and when a fatty acid joins a glycerol molecule in the formation of a triglyceride.

Which is not part of a nucleic acid?

A. Phosphate
B. Nitrogen
C. Sulfate
D. Carbon

Sulfate

A nucleic acid is composed of a five-carbon sugar, a phosphate group, and a nitrogenous base

Which of the following is a digestive enzyme found in the stomach?

A. Bile
B. Pepsin
C. Secretin
D. Trypsin

Pepsin

Pepsin splits proteins into polypeptides in the stomach. Trypsin digests proteins in the small intestine. Secretin is a hormone (not an enzyme) that stimulates the secretion of pancreatic enzymes into the intestine. Bile emulsifies fats, not digests them. Another hormone, gastrin, stimulates the secretion of pepsin and other gastric juices into the stomach.

In the hydrological cycle, plants transfer most of their water to the environment through

A. Transpiration
B. Denitrification
C. Photosynthesis
D. Respiration

Transpiration

Digestion of cellulose by protozoans found in a termite's gut is an example of

A. Autotrophism
B. Commensalism
C. Mutualism
D. Parasitism

Mutualism

Both the termite and the protozoans benefit, so this is mutualism. Termites cannot actually digest cellulose, but protozoans in their digestive systems can. In return, the tiny protozoans receive a home, food, and water.

In tall trees, most water and solutes move through the vascular system of a plant by

A. Active transport
B. Bulk flow
C. Passive transport
D. Osmosis

Bulk flow

Which of the following produces ATP?

I. Glycolysis
II. Oxidative phosphorylation
III. Lactic acid fermentation

A. II only
B. I and II only
C. III only
D. I, II, and III

I, II, and III

What is the shape of the bacteria known as bacilli?

A. Rod-shaped
B. Spiral
C. Spherical
D. Star-shaped

Rod-shaped

What is another name for the light-independent reaction in plants?

A. Germination
B. Photosynthesis
C. Phosphorus cycle
D. Calvin cycle

Calvin cycle

Photosynthesis encompasses both light-dependent and light-independent reactions in plants. The Calvin cycle is light-independent, although it uses the products of light-dependent reactions. During the Calvin cycle, the plant uses ATP and NADPH to convert CO2 and water into organic compounds that the plant can use.

Which organism reproduces via binary fission?

A. Blue whale
B. Salmonella
C. Mushroom
D. Rainbow trout

Salmonella

Salmonella is bacteria. In the asexual process known as binary fission, one parent cell divides into two offspring cells with DNA identical to the parent cell's.

Genetic variation can be introduced into bacteria by all of the following methods EXCEPT

A. Transformation
B. Mutation
C. Transfer of DNA between bacteria through pili
D. DNA amplification

DNA amplification

A movement of muscle that bends a joint to a more acute angle is termed

A. Tonus
B. Extension
C. Diastole
D. Flexion

Flexion

Which is NOT a characteristic of proteins?

A. They can act as hormones
B. They act in cell membrane trafficking
C. They contain genetic information
D. They can catalyze chemical reactions

They contain genetic information

In humans, the site of successful fertilization is most commonly the

A. Fallopian tube
B. Ovary
C. Cervix
D. Uterus

Fallopian tube

Which base appears in DNA but in RNA?

A. Thymine
B. Adenine
C. Cytosine
D. Guanine

Thymine

Thymine is replaced by Uracil in RNA

Which of the following would most likely provide examples of mitotic cell divisions?

A. Longitudinal section of a shoot tip
B. Cross section of muscle tissue
C. Cross section of a leaf
D. Cross section of an anther (site of pollen production in a flower)

Longitudinal section of a shoot tip

Growing parts of an organism are good places to find mitosis. The apical meristems at the root tips and shoot tips of plants have cells that are actively dividing by mitosis. In animals, mitotic divisions are visible in the early (blastula stage) development of embryos. In contrast, a good place to observe meiosis is in a cross section of a plant anther, where haploid pollen cells are being produced.

Polysaccharides are types of

A. Nucleic acids
B. Proteins
C. Enzymes
D. Carbohydrates

Carbohydrates

In addition to lacking a nucleus, what else does a prokaryotic cell lack?

A. Cytoplasm
B. DNA
C. Organelles
D. Ribosomes

Organelles

Prokaryotes do have ribosomes, DNA, and cytoplasm. They lack membrane-bound organelles, which include mitochondria, chloroplasts, and vacuoles as well as nuclei.

Hyperthyroidism is ALWAYS associated with

A. Decreased heart rate
B. High metabolic rate
C. Low body temperature
D. Low blood pressure

High metabolic rate

Hyperthyroidism results in an excess of thyroxin and other thyroid hormones. These increase the basal metabolic rate and blood pressure. Patients with hyperthyroidism are often characterized by sensitivity to heat and nervousness.

The emergence of oxygen in the atmosphere is a result of

A. Photosynthesis
B. Amino acids
C. Mammals
D. Fungi

Photosynthesis

All viruses consist of

A. Proteins and polysaccharides
B. A nucleic acid and a protein coat
C. RNA and a protein coat
D. DNA and a protein coat

A nucleic acid and a protein coat

The vascular tissue composed of living tubular cells that carry sugars from the leaves to other parts of the plant is called

A. Parenchyma
B. Pericycle
C. Phloem
D. Xylem

Phloem

Animal behaviors acquired through imprinting require

A. Conditioning
B. Habituation
C. Spatial learning
D. A sensitive or critical period

A sensitive or critical period

Which of the following is a normal pathway of blood flow?

A. Pulmonary veins to left atrium
B. Pulmonary veins to left ventricle
C. Left ventricle to pulmonary artery
D. Right ventricle to aorta

Pulmonary veins to left atrium

Blood traveling from the left ventricle flows into the aorta, then goes to all areas of the body except the lungs.

Which is not a type of genetic mutation?

A. Frameshift
B. Recombination
C. Substitution
D. Deletion

Recombination

All of the following are homologous structures EXCEPT

A. A human arm
B. A penguin flipper
C. A butterfly wing
D. A bird wing

A butterfly wing

Structures in different species are homologous because they have been inherited from a common ancestor. Insects are not closely related to the other listed animals. Mammals and birds are related by descent from an early reptile. Insect wings, therefore, are analogous structures.

Which of the following are found both in open and closed circulatory systems?

A. Immune cells
B. Arteries
C. Red blood cells
D. Capillaries

Immune cells

Arthropods such as insects or crustaceans have open circulatory systems, in which hemolymph flows freely rather than being locked into vessels. Hemolymph does not transport oxygen, so it contains no RBCs. Within the hemolymph are hemocytes, which are immune cells.

Which of the following types of cells does not go through mitosis?

A. Liver cells
B. Skin cells
C. Sperm
D. Heart cells

Sperm

Which is a byproduct of fermentation in muscle cells?

A. Lactic acid
B. Ethanol
C. Oxygen
D. Pyruvic acid

Lactic acid

Fermentation is an incomplete form of cellular respiration. When it occurs in yeast, pyruvic acid is converted into ethanol and carbon dioxide. When it occurs in muscle cells that are not receiving enough oxygen, pyruvic acid is converted into lactic acid.

A typical human gamete

A. Always contains an X or Y chromosome
B. Has genetic material that has undergone recombination
C. Contains a haploid number of genes
D. All of the above

All of the above

All of the following are examples of evolution EXCEPT:

A. Changes in an allele frequency in a population
B. Divergence of a species into two species
C. Mutations in an individual
D. Changes in an allele frequency in a species

Mutations in an individual

Evolution does not occur for an individual. Only groups (of the same species) evolve.

Organelles that make or synthesize proteins for use in the cell are

A. Centrioles
B. Ribosomes
C. Vacuoles
D. Lysosomes

Ribosomes

Lysosomes hold enzymes that the cell creates. Vacuoles act as storage containers within a cell. Centrioles are little tubelike structures whose only purpose is to assist in cell division, whether through asexual or sexual reproduction.

Which of the following is most likely NOT a characteristic of plants that are adapted to nutrient-poor soils?

A. Large ratio of root surface area to shoot mass
B. Conservative growth rate
C. Symbiotic association with fungus
D. High rate of transpiration

High rate of transpiration

Long chains of amino acids joined by peptide bonds are

A. NADH
B. Inorganic compounds
C. Proteins
D. Lipids

Proteins

An animal cell in a hypertonic solution would

A. Shrink and then swell
B. Exhibit plasmolysis
C. Swell
D. Swell and exhibit turgor

Exhibit plasmolysis

An animal cell in a hypertonic solution would shrink because the concentration of water is greater inside the cell than outside the cell. Since water flows down a gradient, it would flow out of the cell. Plasmolysis means cell shrinking.

Rates of transpiration are influenced by all of the following EXCEPT

A. Leaf orientation
B. Cuticle thickness
C. Leaf surface area
D. Phloem cell density

Phloem cell density

Phloem cells transport sugars and other organic materials; their density does not influence transpiration. Many plants in hot climates have smaller leaves with thicker cuticles to reduce transpiration rates. Other plants have vertically oriented leaves that reduce the amount of surface area exposed to the sun, thus reducing transpiration.

How many net ATP molecules are produced during aerobic cellular respiration?

A. 36
B. 44
C. 2
D. 4

36

Two ATPs are produced in glycolysis, and 34 are produced in the Krebs cycle and electron transport chain for a total of 36 ATPs.

Which does not name a female part of a flowering plant?

A. Pistil
B. Anther
C. Style
D. Stigma

Anther

The anther produces pollen, which contains the male gametes in plant production.

To experience exponential growth, a population must have

A. A large size
B. A small size
C. A high birth rate and a low death rate
D. Few individuals that have reached sexual maturity

A high birth rate and a low death rate

Which are examples of homologous structures?

A. Shark fin and dolphin fin
B. Moth wing and bat wing
C. Fish scale and bird feather
D. Human arm and whale flipper

Human arm and whale flipper

For structures to be homologous, they must not only be parallel in form and function, but must also occur in animals with a common ancestor. Because sharks are fish and dolphins are mammals, their fins are not considered homologous. However, the similarities in form and function between the human arm and the whale flipper — both found in mammals — are enough to make scientists consider these structures homologous.

Which of the following initiates an attack against a specific antigen or pathogen?

A. Plasma cells
B. Macrophages
C. Complement
D. Interferon

Plasma cells

Plasma cells are B cells bearing specific antibodies for binding with a specific antigen.

Which molecules contain only carbon, hydrogen, and oxygen?

A. Carbohydrates and lipids
B. Nucleic acids and proteins
C. Lipids and proteins
D. Proteins and carbohydrates

Carbohydrates and lipids

Carbohydrates and lipids are made up of different combinations of carbon, hydrogen, and oxygen. Proteins are made up of amino acids, which center around carbon atoms and always contain hydrogen and oxygen PLUS nitrogen. Nucleic acids contain carbon, hydrogen, and oxygen in their simple sugars PLUS nitrogen and phosphates.

Cell types of xylem tissue include

A. Fibers and companion cells
B. Parenchyma and chlorenchyma
C. Tracheids and vessel elements
D. Tracheids and companion cells

Tracheids and vessel elements

Tracheids are relatively long, narrow cells that have tapered ends that overlap with the next tracheid. Water passes through the overlapping ends through pits. Vessels are more evolutionarily advanced. They are shorter and wider than tracheids, and the ends that border the next vessel allow for the movement of water between the vessels through perforations, essentially open holes.

What gives a cell its structure?

A. Cytoskeleton
B. Centrioles
C. Cilia
D. Cytoplasm

Cytoskeleton

Which of these is not an example of a lipid?

A. Canola oil
B. Honey
C. Wax
D. Butter

Honey

Honey is primarily carbohydrate (glucose and fructose)

Which of the following would be activated first in response to. abody cell that has been invaded by a virus?

A. Antibodies
B. Cytotoxic T cells
C. Macrophages
D. Natural killer cells

Cytotoxic T cells

As part of the cell-mediated immune response, cytotoxic T cells would attack the abnormal body cell first. Once the abnormal cell is lysed, nonspecific attacks by macrophages and other phagocytes would occur.

Which of the following elements best describes organic?

A. Oxygen
B. Nitrogen
C. Carbon
D. Water

Carbon

The term organic means matter that is living or alive. Organic matter describes compounds that are derived from carbon. Oxygen, water, and nitrogen are essential for much of the life on earth, but neither are the backbone of organic matter.

Chromosomes composed of distinct units are called

A. Organic catalysts
B. Complex carbohydrates
C. Substrates
D. Genes

Genes

Genes are working units of heredity. They occupy a specific place on a chromosome.

Which type of sugar is a disaccharide?

A. Galactose
B. Sucrose
C. Fructose
D. Glucose

Sucrose

Sucrose is made up of glucose and fructose. Sucrose, lactose, and maltose are all disaccharides, formed of two monosaccharides. The other choices listed are monosaccharides, or simple sugars.

What is the genus of human beings?

A. Homo
B. Primates
C. Chordata
D. Mammalia

Homo

Human beings are genus Homo, species sapiens. Others in our genus in the past included Homo erectus, Homo neanderthalensis, and Homo habilis.

Which of the following is correct about eukaryotic organisms?

A. They are the simplest form of organism
B. They contain a nucleus that holds DNA
C. They are bacteria
D. They do not have a nucleus

They contain a nucleus that holds DNA

Which organism reproduces via spore formation?

A. Staphylococcus
B. Smallmouth bass
C. Lemon tree
D. Shelf fungus

Shelf fungus

Fungi, algae, moss, and ferns may release spores, which allow them to reproduce asexually. If the spores land in a place hospitable to germination, they will grow into a clone of the parent plant.

Which part of an animal cell contains the most water?

A. Cytoplasm
B. Ribosome
C. Cell membrane
D. Nucleus

Cytoplasm

The cytosol portion of the cytoplasm is formed from water, salts, and organic molecules. It makes up a large portion of the cell.

When NADH is converted to NAD, the process is categorized as

A. Reduction
B. Catalysis
C. Oxidation
D. Dehydration

Oxidation

Oxidation is always coupled with reduction, that is, when one molecule is oxidized, another is reduced. Reduction is simply the opposite of oxidation. The conversion of NADH to NAD indicates a loss of a hydrogen ion, and thus oxidation. There are three conditions that define oxidation: (1) when a molecule gains an oxygen atom, (2) when a molecule loses an electron, or (3) when a molecule loses a hydrogen ion (proton)

Which of the following statements is NOT correct?

A. RNA contains uracil
B. DNA cannot be altered
C. RNA is single-stranded
D. DNA codes for proteins

DNA cannot be altered

DNA can mutate and change.

A catabolic reaction of proteins would create which of the following molecules?

A. Fatty acids
B. Amino acids
C. Glycerides
D. Glucose

Amino acids

Which animals has an open transport system?

A. Penguin
B. Earthworm
C. Trout
D. Crayfish

Crayfish

Crayfish and other crustaceans have a system in which blood circulates through blood vessels that open into spaces in their body cavities

Which of the following is NOT a biological function of lipids?

A. Energy
B. Joint lubrication
C. Cushioning and insulation
D. Precursors to the synthesis of signaling molecules

Joint lubrication

Joints are places where two bones meet. The joint itself is encased in a synovial fluid capsule, which is not a lipid.

What kind of symbiosis exists between a pneumonia bacteria and a human?

A. Commensalism
B. Mutualism
C. Competition
D. Parasitism

Parasitism

A parasitic relationship is in which one organism (in this case, the bacterium) benefits to the detriment of another (in this case, the human).

Which plant part produces pollen?

A. Style
B. Pistil
C. Anther
D. Stigma

Anther

The anther is part of the stamen. It produces pollen, which later lands on the stigma, descends down the style, and enters the ovary.

Which is NOT a product of glycolysis?

A. Oxygen
B. NADH
C. ATP
D. Pyruvate

Oxygen

Glycolysis converts glucose into pyruvate, releasing energy in the form of ATP and NADH. Oxygen is neither used for the reaction nor released as a byproduct.

Where are ribosomes found within a cell?

A. Within the cytoplasm and endoplasmic reticulum
B. Only within the cytoplasm
C. Only within the nucleus
D. Within the cytoplasm, mitochondria, and chloroplasts

Within the cytoplasm, mitochondria, and chloroplasts

Among the evidence for the Endosymbiotic Theory are the facts that chloroplasts and mitochondria have their own separate genome, bacteria-like DNA polymerases, and bacteria-like ribosomes. The ribosomes of the eukaryotic cell are found only within the cytosol, although they are commonly closely associated near the endoplasmic reticulum (ER).

Which of the following describes the creation of ATP in the absence of oxygen?

A. Fermentation
B. Aerobic respiration
C. Metabolism
D. Krebs cycle

Fermentation

Fermentation creates ATP without oxygen. Metabolism as a whole absolutely brings about energy; however, that energy is in the form of breaking down food into smaller components. These components may eventually be used to create ATP, but that does not describe metabolism as a whole. Aerobic respiration, which includes the Krebs cycle, requires oxygen to work.

Which organelle is responsible for protein synthesis?

A. Cell membrane
B. Mitochondrion
C. Ribosome
D. Vacuole

Ribosome

These beadlike organelles are located in the cytoplasm of nearly all cells, on the rough endoplasmic reticulum. They assemble the proteins that the cell uses to grow, repair itself, and control processes.

Which is found in animal cells but NOT in plant cells?

A. Golgi apparatus
B. Vacuole
C. Cytoplasm
D. Centriole

Centriole

The centriole is involved in animal cell reproduction. Vacuoles are found in plant cells but not in animal cells.

Which is NOT a form of passive transport?

A. Endocytosis
B. Diffusion
C. Osmosis
D. Filtration

Endocytosis

The four forms of passive transport are diffusion, facilitated diffusion, filtration, and osmosis. Endocytosis is active transport in which a cell uses energy to form a vacuole and engulf molecules.

In the taxonomic system, a class is grouped into which level?

A. Order
B. Family
C. Species
D. Phylum

Phylum

A researcher characterizes a polymer that consists of glycerol molecules. What does she write in her notes about this polymer?

A. These molecules will form lipid biomolecules
B. This polymer is capable of storing very little energy
C. The glycerol molecules are covalently bonded together
D. This polymer will help transmit genetic information in a cell

The glycerol molecules are covalently bonded together

A researcher characterizes the amino acid chain and structure of a novel substance. What type of substance is the researcher studying?

A. Fat
B. DNA
C. Enzyme
D. Sucrose

Enzyme

A study was performed to evaluate which type of road salt deiced a road most quickly. What is the independent variable?

A. Deicing time period
B. Road used for deicing
C. Type of road salt used
D. Amount of road salt used

Type of road salt used

A researcher predicts that a new drug will lower cholesterol in people. What is this statement called?

A. Law
B. Theory
C. Variable
D. Hypothesis

Hypothesis

Which trait is used to distinguish living things from nonliving things?

A. Size
B. Genetics
C. Homeostasis
D. Environment

Homeostasis

Why did it take many years for the cell theory to be developed?

A. Advancements in microscopy took place slowly
B. Cells were difficult to isolate for experimental analysis
C. Researchers believed a cell formed from preexisting cells
D. Scientists already proved that cells were essential for life

Advancements in microscopy took place slowly

A researcher discovers a cell that is less than 0.5 millimeters in diameter. This cell has pili surrounding its cell wall. What does the researcher classify this cell as?

A. Autotroph
B. Eukaryote
C. Heterotroph
D. Prokaryote

Prokaryote

Which structure do cells rely on for movement?

A. Flagellum
B. Microtubule
C. Pili
D. Vesicle

Flagellum

What is a characteristic of eukaryotes?

A. These organisms are all unicellular
B. They lack a membrane-bound nucleus
C. Many organelles are in their cytoplasm
D. Bacteria and plants are examples of eukaryotes

Many organelles are in their cytoplasm

What cellular process do autotrophs rely on to obtain energy?

A. Carbon fixation
B. Cell respiration
C. Photosynthesis
D. Gluconeogenesis

Photosynthesis

How is a plant cell different from an animal cell?

A. It lacks a cell wall
B. It is rectangular
C. It has many vacuoles in its cytoplasm
D. It traps sunlight using its mitochondria

It is rectangular

Glycolysis breaks down

A. acetyl coA
B. ATP
C. glucose
D. pyruvate

Pyruvate

During the G2 phase, more copies of tubulin are made to separate

A. histones
B. chromosomes
C. daughter cells
D. sister chromatids

Chromosomes

Which process involves crossing over?

A. Mitosis
B. Meiosis
C. Calvin cycle
D. Cell respiration

Meiosis

Meiosis is a form of cell division that occurs when DNA from homologous chromosomes is exchanged. This exchange, or crossing over, increases genetic diversity in a population.

Chromosomes line up during ___________

A. anaphase
B. interphase
C. prometaphase
D. telophase

Prometaphase

During prometaphase, the spindle fibers (that are attached to the centromere of the chromosome) pull the duplicated chromosome toward the poles of the cell

What is the correct order of the stages of the cell cycle?

A. G1, S, G2, M
B. G2, S, G1, M
C. M, S, G2, G1
D. S, M, G1, G2

G1, S, G2, M

What is made only during the light reaction phase of photosynthesis?

A. ATP
B. CO2
C. H2O
D. FADH2

CO2

Which of the following is a segment of DNA that transmits information from parent to offspring?

A. Centromere
B. Chromatid
C. Chromosome
D. Gene

Gene

The replication of DNA ends with a twisted strand called a ___________

A. base pair
B. nucleic acid
C. double helix
D. single strand

Double helix