Bio 156

A monohybrid cross is

a breeding experiment in which the parental varieties differ in only one trait.

Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's firstborn child is female and second-born child is male?

25%

A carrier of a genetic disorder who does not show symptoms is most likely to be __________ to transmit it to offspring.

heterozygous for the trait and able

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes?

Dd and Dd

Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of

incomplete dominance.

The expression of both alleles for a trait in a heterozygous individual illustrates

co-dominance.

Which of the following terms refers to the situation where a single phenotypic characteristic is determined by the additive effects of two or more genes?

polygenic inheritance.

Linked genes generally

do not follow the laws of independent assortment.

What is the normal complement of sex chromosomes in a human male?

one X chromosome and one Y chromosome

Recessive X-linked traits are more likely to be expressed in a male than a female because

the male's phenotype results entirely from his single X-linked gene.

A karyotype is most like which of the following?

Photographs of every couple at a high school prom

Nondisjunction occurs when

members of a chromosome pair fail to separate.

Solve this monohybrid genetics problem: Black hair is governed by the dominant gene (B) and blond hair is determined by the recessive gene (b). In this monohybrid cross, if both parents are heterozygous, what percentage of the offspring would be expected to have blond hair?

25%

Which of the following is the BEST description of Mendel's principle of independent assortment?

Genes for different characteristics sort into eggs or sperm without regard for the position of other genes on other chromosomes.

If both parents in a dihybrid cross are heterozygous for both traits, the expected phenotypic ratio in the offspring would be

9:3:3:1

Solve the following multiple allele problem: Susan, a mother with Type B blood, has a child with Type O blood. She claims that Craig, who has Type A blood, is the father. He claims that he cannot possibly be the father. Further blood tests ordered by the judge reveal that Craig is AA. The judge rules that

Craig is right and doesn't have to pay child support.

Different alleles of the same gene are found

at the same place on homologous chromosomes.

If you had an individual who showed a dominant phenotype and you wanted to find out if the individual was homozygous or heterozygous, you could do a test cross. You would cross the unknown with a known

homozygous recessive.

Many genetic disorders of humans are caused by

recessive alleles.

TRUE OR FALSE?
Most human genetic diseases are treatable if caught early.

FALSE

A person who has type AB blood illustrates the principle of

co-dominance.

Sometimes, linked genes are not inherited because they are broken apart during the formation of the gametes. These breaks are caused by

crossing over.

How many sex chromosomes are in an egg or a sperm?

one

By studying a karyotype, a prospective parent would be able to tell

if there is an alteration in the number of chromosomes.

In the gene arrangement ABCDEFG breaks and a segment repositions itself so that the segment now reads ABEDCFG, what specific kind of mutation has occurred?

Inversion

Which of the following genotypes would be homozygous dominant for both alleles?

DDEE

If a colorblind woman marries a colorblind man, the chances of any daughter being of normal vision is

0%

When you trace the occurrence of a specific characteristic through your past ancestry, you are constructing a family ______________.

pedigree

Human skin color varies greatly from one individual to another. The specific genetic situation to account for this fact is

polygenic inheritance - several genes act together to govern the phenotype of a certain characteristic.

Mendel was fortunate to work out the laws of segregation and independent assortment because he used an organism that reproduced quickly and in which the traits were discrete (easy to observe). Mendel's organism of choice was the

pea plant

The monomers of DNA and RNA are

nucleotides.

The copying mechanism of DNA is most like

using a photographic negative to make a positive image.

When one DNA molecule is copied to make two DNA molecules, the new DNA contains

50% of the parent DNA.

The one gene-one polypeptide theory states that

the function of an individual gene is to dictate the production of a specific polypeptide.

The transfer of genetic information from DNA to RNA is called

transcription.

Experiments have demonstrated that the words of the genetic code (the units that specify amino acids) are

three-nucleotide sequences.

Which of the following enzymes catalyzes the linking of RNA nucleotides to form RNA?

RNA polymerase

Translation consists of which of the following?

the conversion of genetic information from the language of nucleic acids to the language of proteins

A physical or chemical agent that changes the nucleotide sequence of DNA is called

a mutagen.

Replication of DNA is said to be semiconservative because

each separated strand serves as a template to make an exact copy.

Each DNA strand has a backbone that consists of alternating

sugar and phosphate molecules.

DNA polymerase

All of the above

If the DNA triplets were ATG-CGT, the mRNA codons would be _____________.

UAC-GCA

A chromosome that has been broken and rejoined in a reversed sequence has undergone which of the following mutations?

Inversion.

Which of the following is the enzyme that HIV uses to synthesize DNA on an RNA template?

reverse transcriptase

One type of virus that infects bacteria is called a(n)

phage

Sticky Ends are

DNA fragments with single-stranded ends.

DNA ligase binds

nucleotides together.

In the process of human gene cloning using recombinant plasmids, the bacterial plasmid

functions as a vector.

Retroviruses such as HIV use __________ to convert information stored in their RNA to information stored in DNA.

reverse transcriptase

Genetically modifying __________ cells may directly affect future generations.

germ

If you commit a crime, you need to make sure that you do not leave even the smallest speck of blood, hair, etc., from your body behind, because if you do, the DNA in this material can be amplified by __________, subjected to genetic analysis, and used to identify you as the perpetrator of the crime.

PCR

Segments of eukaryotic DNA that can move or be copied from one site to another in the genome are called

transposons.

Gel electrophoresis separates DNA molecules on the basis of

their lengths

When a virus takes over the machinery of a cell, it forces the cell to manufacture

more viral particles.

If one sticky end has the nucleotide sequence TTAA exposed, the piece of DNA that will come in and attach to that sticky end will have the sequence ___________.

AATT

A harmless variant or derivative of a pathogen that is used to prevent infectious disease is called a __________.

vaccine

In the gel electrophoresis chamber, the DNA fragments migrate toward the __________ charged pole.

positively

A transgenic organism has acquired genes from

another species.

Most scientists do not consider viruses to be alive because

they are unable to reproduce on their own.

Epithelial tissues are characterized as such because they

cover both external and internal body surfaces.

Which muscle tissue is responsible for voluntary movement?

skeletal muscle only

Which of these is an example of positive feedback?

labor pains increasing

What kind of connective tissue has a liquid matrix?

blood

The basic unit of nervous tissue is the

neuron

Structure in the living world is organized at hierarchal levels. Which of the following choices lists several of these, from least inclusive to most inclusive?

cell → tissue → organ → organ system → organism

The main function of muscle tissue is __________.

contraction

Which of the following is most likely to be responsible if your blood sugar were to come back down following a rise?

a homeostatic mechanism based on negative feedback

When body temperature is too low, which of the following occurs?

Blood vessels in the skin contract.

The organ in the body most responsible for maintaining water and salt balance is the __________.

kidney

Which of the following neurons is part of the peripheral nervous system?

Sensory neuron and motor neuron

The minimum change in a membrane's voltage that must occur to trigger an action potential is the ____________.

threshold

The movement of an action potential along a neuron is most like

a crowd at a sporting event doing the wave around a stadium.

Which of the following neurotransmitters is associated with sleep, mood, attention, and learning?

Serotonin

Arthritis is a common result of aging, affecting a person's ability to

move their joints.

Muscles are connected to bones by _____________.

tendons

Functionally, what is the muscle fiber's fundamental unit of contraction?

sacromere

At a chemical synapse, what causes the ion channels on the receiving cell's membrane to close?

The neurotransmitter is broken down by an enzyme.

Digestion is the

mechanical and chemical breakdown of food.

Muscular action propels food through the alimentary canal by a process called __________.

peristalsis

How does Helicobacter pylori cause gastric ulcers in humans?

It damages the stomach's mucous coat.

Which of the following mechanisms helps prevent the gastric juice from digesting the stomach lining?

mucus lining the inside surface of the stomach

Someone with liver failure will, in particular, have problems with the digestion and absorption of ___________.

fats

Absorption of water is one major function of which of the following structures?

colon

The tongue does all of the following except ___________.

Secrete saliva

Movement of food from the stomach into the esophagus is usually prevented by __________.

sphincter

Which of the following is the usual cause of heartburn?

backflow of acid chyme from the stomach into the lower esophagus

Bile from the liver is stored in the _____________ before entering the intestine.

gallbladder

The epithelial cells lining the intestine have surface projections that increase the area for absorption. These projections are called ________________.

microvilli

The two major divisions of the nervous system are the _____________.

CNS and PNS

Which of these carry oxygen-poor blood?

pulmonary arteries

Which of these carry oxygen-poor blood?

pulmonary arteries

Why does the left ventricle have a thicker wall than the right ventricle?

A more muscular wall is required to supply the pumping that powers the flow of blood into the systemic circuit.

The one-way flow of blood in veins is maintained by ______________.

valves

Blood pressure is lowest in ___________.

veins

If your blood pressure were 120/70, it would mean that

Your blood pressure during systole is 120 and your blood pressure during diastole is 70.

Plasma is primarily what?

water

You increase your risk of cardiovascular disease by reducing your consumption of ________.

fruits and vegetables

What path does a molecule of oxygen take from the nose to the respiratory surface?

Pharynx → larynx → trachea → bronchus → bronchiole → alveolus

Breathing is regulated by

autonomic centers in the brain.

Oxygen is mostly transported through the body

bound to hemoglobin.

Within the lungs, gas exchange occurs across ______________.

alveoli

A new flu vaccine is needed every year because

new flu strains are regularly evolving.

Which response occurs as part of our nonspecific defense system?

Inflammation

Histamine

causes local swelling of the affected area.

A substance that can elicit an immune response is called a(n) _____________.

antigen

Anaphylactic shock is an example of an ________________.

allergic response

Which gland exerts primary control over the concentration of sugar in the blood?

pancreas

Which of the following hormones causes a rise in the concentration of sugar in the blood?

glucagons

When the concentration of glucose in the blood rises following the digestion of a meal, what is the hormonal response?

Insulin is released, but not glucagons.

What is the metabolic abnormality that underlies the characteristic symptoms of diabetes mellitus?

The body's cells can't absorb enough glucose from the blood.

Where in a woman's reproductive tract does fertilization most often take place?

In the upper part of the oviduct

A vasectomy

prevents the movement of sperm into the urethra.

A diaphragm functions as a birth control device by ______________.

preventing the movement of sperm into the uterus

Which of the following is not one of the endocrine glands?

Alveoli glands

Which of the following glands produces hormones that enable the body to respond to stress?

Adrenal glands

Maintaining a dynamic balance between too much or too little calcium in the blood, or insulin in the blood is described by the general term:

Homeostasis

All of the following statements about hormones are correct except:

They are carried by the nervous system.

In which of the following ways are mature human sperm and ova similar?

They both have the same number of chromosomes.

Which of the following sequences does not indicate a DIRECT pathway that blood might follow in human circulation?

Right ventricle → pulmonary vein