Biology exam 3

What would be the first codon translated in the mRNA sequence 5'-GGAAUGAAACAGGAACCC-3'?

- AUG

An ion is an atom that has

a net negative or positive charge, with number of electrons different from number of protons.

In a covalent bond, atoms

share electrons

Alternate forms of the same gene

- are alleles.

In the biology lab, you observed that your lab partner's blood type is AB. The placement of the A and B molecules on each cell is controlled by proteins, coded by different versions of the same gene. Having both is an example of

- codominant inheritance.

Crossing-over is more likely to separate genes on a chromatid if they are

- far apart

The correct sequence for the phases of the cell cycle, starting with a newly divided cell, is

- interphase .mitosis .cytokinesis.

Which of the following is the large lymphoid organ in the abdomen that produces and stores large amounts of white blood cells?

- spleen

It is thought that eukaryotes probably originated about __________ years ago.

-1.5 billion

Which of the following RNA strands is complementary to the DNA sequence 5'-ATCGATCG-3'?

-3'-UAGCUAGC-5'

It is thought that the first cells probably arose about __________ years ago.

-3.85 billion

Mendel's monohybrid cross of Tt parents resulted in a tall-to-short ratio of

-3:1

What is an example of adaptive cell-mediated immunity?

-A cytotoxic T cell destroying a virus-infected cell.

If asked to sort cards of immune responses into boxes marked "active immunity" and "passive immunity," which of the following cards would go into the "passive immunity" box?

-A fetus acquiring antibodies through the placenta, and a person receiving an injection of antibodies.

Why are the leading causes of death in high-income countries heart disease, stroke, and cancer, while in low-income countries infectious diseases are the leading causes of death?

-Access to sanitation, vaccines, and antibiotics is greater in high-income countries.

Mitochondria are proposed to have evolved before chloroplasts based on which observation?

-All eukaryotes have mitochondria, but not all eukaryotes have chloroplasts.

Identify the correct comparison between the human X and Y chromosomes.

-All of the answer choices are correct. -Although both are sex chromosomes, they do not share the same genes. -Only the Y chromosome is always found without a homologous match. -The X chromosome is paired with a homologous match in human females.

Nondisjunction may cause

-All of the answer choices are correct. -Klinefelter syndrome. -Jacobs syndrome. -trisomy 21. -Turner syndrome

RNA differs from DNA in that

-All of the answer choices are correct. -RNA contains ribose. -Some RNA molecules can catalyze bond formation. -RNA contains uracil. -RNA is usually single stranded.

How does fever help fight infection as part of the innate defense?

-All of the answer choices are correct. Correct -Fever reduces the iron level in the blood, thereby retarding the growth of some bacteria. -Fever speeds up the rate of phagocytosis. Fever kills some bacteria. -Fever inactivates (kills) some viruses.

Meiosis is a process that produces

-All the answers are correct -Sperm cells, egg cells, gametes, and haploid cells

In meiosis, homologous chromosomes separate during

-Anaphase I

Photosynthesis probably originated during the __________ eon, and most likely used __________ as an electron donor.

-Archean; hydrogen sulfide

A country's ecological footprint can be calculated by multiplying its population size by the footprint of each individual. Why are some ecologists concerned about the ecological footprint of a country like India?

-Both its population and standard of living are increasing.

Of the following statements, which does not correlate a type of RNA with its function?

-Complementary RNA reorders the amino acids in a protein to ensure their correct sequence

Mutations are usually rare, because

-DNA polymerase quickly corrects mismatched nucleotide base pairs.

Why does a replication fork have a leading and lagging strand?

-DNA synthesis always goes from 5' to 3'.

The first amphibians appeared during the __________ period.

-Devonian

Given this information from one element in the periodic table of elements, the number of neutrons plus protons is

-Given this information from one element in the periodic table of elements, the number of neutrons plus protons is

Why does sexual reproduction produce more genetic variability in a population than asexual reproduction?

-In addition to the variation that meiosis creates, fertilization mixes parental genetics

An ionic bond

-In an ionic bond,

Why do lymph nodes often become swollen during an infection?

-Macrophages move to lymph nodes after engulfing pathogens.

Jawless fishes were the first vertebrates to leave fossil evidence during the __________ period.

-Ordovician

Placental mammals appeared during the __________ period.

-Paleogene

The amniote egg, in which an embryo could develop completely on dry land, arose during the __________ period.

-Permian

Every year the common flu vaccine is designed to protect against three different strains of the influenza virus. How is your body able to raise antibodies against so many new forms of the flu virus?

-Recombination of the gene used to make antibodies leads to variability.

In what phase of the eukaryotic cell cycle are the chromosomes replicated?

-S phase of interphase

Why would a cancer cell need to induce angiogenesis?

-Why would a cancer cell need to induce angiogenesis?

Rh incompatibility is due to an immune reaction in a pregnant woman to which of the following?

-a foreign antigen on red blood cells

The three major components in a nucleotide are

-a nitrogen base, a five-carbon sugar, and a phosphate group.

The primary building block (monomer) of nucleic acids is

-a nucleotide.

The difference between a population and a community in the same location is that

-a population includes members of one species, while a community includes members of multiple species.

In order for a cell to become cancerous, oncogenes must be ________, or tumor suppressors must be ________.

-activated; inactivated

In a molecule of DNA, hydrogen bonds hold together the two strands, such as hydrogen bonds that form when

-adenine pairs with thymine.

The four nitrogen bases found in RNA are

-adenine, cytosine, guanine, and uracil.

Mitochondria are proposed to have arisen after host cells engulfed __________ in endosymbiosis

-aerobic bacteria

Antigens attached to harmless substances found in food, dust mites, pollen, fur, and some oils in plants that elicit an immune attack are called

-allergens

The primary building block (monomer) of proteins is

-an amino acid.

In a survivorship curve, a type II species, like a songbird, is a species that has

-an equal probability of dying at any age.

A Y-shaped protein that proliferates in response to a specific antigen and recognizes these antigens is a(n)

-antibody

Which of the following is part of the adaptive, rather than the innate, immune response?

-antibody production

by removing different combinations of introns

-anticodon

Linked genes

-are found on the same chromosome.

The number of individuals produced per individual per unit time in a population is its __________ rate.

-birth

In the biology lab, you observe animal cells under a microscope. In one slide you see the nucleus with two nucleolus areas of compact chromatin. The value in packaging DNA in tighter forms of chromatin is for

-both DNA mobility and protection and regulation in mitosis and transcription.

A male expresses

-both dominant and recessive alleles on his X chromosome.

In eukaryotic cells, how can a single gene encode for more than one protein?

-by removing different combinations of introns

The 5' and 3' designations used in reference to DNA and RNA sequences are assigned to the

-carbon atoms of deoxyribose and ribose.

The maximum number of individuals that a habitat can support is its

-carrying capacity.

In a process called __________, an army of plasma cells and memory cells are produced from stimulated B cells.

-clonal selection

Among enzymes required for DNA replication, ligases are needed to form ______ bonds between nucleotides to join DNA segments.

-covalent

Within a single molecule of water, as shown, ____ bonds are formed between oxygen and hydrogen.

-covalent

Which of the following may occur in meiosis but not in mitosis?

-crossing-over

Recombinant chromatids have a mix of paternal and maternal alleles due to

-crossing-over between the linked genes.

The number of individuals that die in a population per unit time is its __________ rate.

-death

If a sperm cell combines with an egg cell, then the result is a

-diploid cell.

By ignoring a checkpoint in the cell cycle, a cancer cell may

-divide before its DNA is completely replicated.

Mendel observed that some genetic traits seemed to mask others in the pea plants. The masking trait is referred to as the

-dominant trait.

Inheritance of autosomal dominant disorders require ___ to pass on the allele, while inheritance of autosomal recessive disorders require ___ to pass on the allele for it to be expressed in the offspring.

-either the mother or the father; both the mother and the father

A visiting scientist is introduced to you, and has a current project studying initiation, elongation, and termination. As a result, you know she is studying

-either transcription or translation.

A phagocyte is a cell that

-engulfs other cells and debris.

The role of the enzyme telomerase is to

-extend telomeres which enables cells to continuously divide.

White blood cells are produced

-from bone marrow stem cells.

An example of a density-independent factor that affects a population's growth is

-frost killing all of your tomato plants.

Sister chromatids are

-genetically identical and attached to each other at the centromere

If any of the traits that Mendel worked with had been due to linked genes, his dihybrid crosses would have

-had different results.

During DNA replication, the enzyme that unwinds and separates the DNA double-helical molecule is

-helicase.

Chromosomes that look alike and carry the same sequence of genes for the same traits, such as these shown from two parents, are

-homologous chromosomes.

Sugars like glucose (C6H12O6) dissolve well in water because sugars form ____ bonds with water.

-hydrogen

In DNA, the "rungs" between the two strands of DNA are formed from the

-hydrogen bonds between nitrogen base pairs.

The movement of individuals into a population is termed

-immigration.

A Barr body is a(n)

-inactive X chromosome

In eukaryotic cells, the cell cycle is divided into two main phases in which the cell spends most of its time and metabolic energy. These two phases are

-interphase and mitosis.

The process by which homologous chromosomes exchange genetic material

-is crossing-over.

Which of Mendel's laws states that two alleles separate during the formation of gametes?

-law of segregation

A population with a large fraction of pre-reproductive individuals is common in __________-developed countries; this population will most likely __________ in size.

-less; increase

During DNA replication, the lagging strand is synthesized by forming Okazaki fragments. The enzyme that joins Okazaki fragments together is

-ligase.

B cells and T cells are

-lymphocytes

Which of the following exhibit phagocytic activity?

-macrophages and neutrophils

At the end of the Cretaceous period, a mass extinction occurred and coincided with the impact of a large asteroid that hit Earth near the Yucatán peninsula; this impact likely produced __________, which created uninhabitable conditions.

-massive volumes of debris that blocked out sunlight

Immunological memory results from the production of

-memory B cells and memory cytotoxic T cells.

In clonal selection, activated T helper cells divide and differentiate into __________ cells and into __________ cells that help activate cytotoxic T cells and B cells

-memory; effector

The eukaryotic cell will complete the ______ portion of the cell cycle to ______.

-mitosis; divide the replicated chromosomes before the cell splits into two daughter cells

A population with a large fraction of post-reproductive individuals is common in __________-developed countries; this population will most likely __________ in size.

-more; decrease

An amino acid contains a structural "backbone" chain of

-nitrogens and carbons

A single strand of DNA consists of covalently bonded building blocks calle

-nucleotides.

A group of prokaryotic genes that are controlled together is a(n)

-operon.

Emigration happens when individuals move __________ a population, while immigration happens when individuals move __________ a population.

-out of; into

Water has unique properties which include its strength as a solvent; its three environmental stages of solid, liquid, and gas; and its temperature regulation. These properties are due to polar covalent bonds between oxygen and hydrogen. The polar covalent bonds are a result of

-oxygen being more electronegative and therefore attracting more electrons than hydrogen.

Which of the following can be a target of an autoimmune disease but is not considered to be part of the immune system?

-pancreas

The mass extinction of the Permian period

-paved the way for the age of dinosaurs. -was caused by a drop in sea level. -was caused by a rise in global temperature. -was caused by a long series of volcanic eruptions. -All of the answer choices are correct.

Chloroplasts are proposed to have arisen after host cells engulfed __________ in endosymbiosis, allowing the engulfed cell to remain, with specialized function.

-photosynthetic bacteria

In humoral immunity, cells that are produced by activated B cells and function by secreting antibodies are called

-plasma cells.

In biology lab, your class counts the number of people with different colors of hair and eyes. Your instructor says that these traits are variable and difficult to trace in each family. The reason is that these two traits depend on more than one gene, and are called

-polygenic.

Meiosis is a process used for

-production of gametes

An embryo fish in its egg cannot survive outside the egg because it has underdeveloped tissues and organs needed for survival. The embryo has a large number of cells undergoing mitosis for the purpose of

-production of new cells that can differentiate and specialize for different functions.

Apoptosis is the process of

-programmed cell death

In meiosis, homologous chromosomes align next to one another during

-prophase I.

The mass number is defined as the total number of __________ of an atom.

-protons and neutrons

The atomic number of an element is the number of

-protons in the nucleus.

You have an opportunity in biology lab to observe the prepared, stained karyotypes of a stallion, a mare, and their foal offspring horses. Banding patterns of some of the autosomes from the foal match those of the stallion, while others from the foal match those of the mare. This variability is produced in meiosis due to

-random orientation of chromosome pairs

Graphed from 10,000 BCE to 2020, as shown below, the global human population

-shows the typical curve of exponential growth.

Evidence supporting the idea that mitochondria and chloroplasts in present-day cells originated as independent organisms includes

-similarities in DNA sequences between mitochondrial and bacterial genomes. -similarities in size and shape between mitochondria and some bacteria. -similarity between photosynthetic pigments in chloroplasts and cyanobacteria. -similarity in the way mitochondria, chloroplasts, and bacteria reproduce. -All of the answer choices are correct.

After replication, in eukaryotic cells, the identical copies of the chromosome are each called a

-sister chromatid

If a chromosome in one of your bone cells becomes mutated, you will not pass this mutation on to your children because

-somatic cells cannot undergo meiosis.

Physical and chemical barriers that form the first line of innate defense include

-tear fluid from the eye. -an unpunctured skin. -mucus and cilia of the respiratory tract. -the acidity of the stomach. -All of the answer choices are correct.

The step of translation in which release factors bind to a stop codon is

-termination.

In humans, germ cells are located in the

-testes and ovaries

Genotype refers to

-the combination of alleles in an individual

The central dogma refers to

-the flow of genetic information in cells, from a gene sequence in DNA to a specific protein.

In a survivorship curve, a type I species, like a human or elephant, is a species that has

-the highest probability of dying as it reaches its maximum life span.

In a survivorship curve, a type III species, like most insects and plants, is a species that has

-the highest probability of dying at a very young age

You collect and measure samples of ice and surrounding liquid water from a stream in the winter. You find that you collected the same number of water molecules in each form. The volume of the ice samples are larger than the liquid water samples. This is a result of

-the hydrogen bonds between the water molecules being in a fixed position that increases the volume and decreases the density of the ice.

In eukaryotic cells, if you compared the DNA sequence of a gene with the sequence of the processed mRNA that was transcribed from the gene you would find

-the mRNA is shorter because it does not contain introns.

Phenotype refers to

-the observable expression of the genes in an individual

In the lac operon, the protein that binds to the operator to prevent transcription is

-the repressor.

At a given locus, homologous chromosomes have

-the same genes but can have different alleles.

The nucleotides called pyrimidines include

-thymine and cytosine.

A diploid cell only has two copies of most genes, but can make hundreds of copies of a protein from those genes per second because

-transcription can repeat and make multiple mRNA copies of genes, and multiple ribosomes can translate the same mRNA.

Which proteins initiate transcription in eukaryotes by recognizing sequences within the promoter region of a gene and attracts RNA polymerase?

-transcription factors

The process used by cells to convert the mRNA "message" into a sequence of amino acids is

-translation.

The first energy shell of an atom has one orbital. Therefore, it can contain a maximum of ________ electron(s).

-two

Diploid (2n) means having

-two complete sets of homologous chromosomes

In meiosis I, cytokinesis usually occurs after telophase I and produces

-two haploid cells.

Primitive reptiles first appeared during the __________ period.

Carboniferous

Which scientist is given credit for proposing the endosymbiont theory?

Lynn Margulis