biology: week 9 - 12

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

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

a foreign antigen on red blood cells

an ion is an atom that has

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

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 nuclei 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

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 higher-income countries

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, uracil

mitochondria are proposed to have arisen after host cells engulfed _______ in endosymbiosis

aerobic bacteria

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

all eukaryotes have mitochondria, but not all eukaryotes have chloroplasts

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 amnio 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 thee antigens is a(n)

antibody

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

antibody production

a three-base sequence, found on the bottom loop of tRNA, that is complementary to a sequence of three bases in mRNA is a(n)

anticodon

linked genes

are found on the same chromosome

in an ionic bond,

atoms, having gained or lost electrons, attract one another with opposite charges

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.

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

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

primitive reptiles first appeared during the _______ period

carboniferous

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

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

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

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

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

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, and used the term __________ to describe these traits.

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.

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

far apart

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

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 & mitosis

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

interphase- mitosis - cytokinesis

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

why do lymph nodes often become swollen during an infection?

macrophages move to lymph nodes after engulfing pathogens

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 Yucatan 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 & carbons

a single strand of DNA consists of covalently bonded building blocks called

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

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 a 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

the mass number is defined as the total number of ________ of an atom

protons & neutrons

the atomic number of an element is the number of

protons in the nucleus

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 gene used to make antibodies leads to variability

in a covalent bond, atoms

share electrons

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

sister chromatid

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

spleen

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

- an unpunctured skin - the acidity of the stomach - mucus and cilia of the respiratory tract - tear fluid from the eye

how does fever help fight inflection as part of the innate defense?

- 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

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

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

RNA differs from DNA in that

-some RNA molecules can catalyze bond formation -RNA contains uracil -RNA contains ribose -RNA is usually single stranded

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

termination

It is thought that eukaryotes probably originated about __________ years ago

1.5 billion

Nitrogen element

14, which is approximately the same as the atomic weights

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

AUG

genotype refers to

the combination of alleles in an individual

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

Archean; hydrogen sulfide

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 insect 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

Why would a cancer cell need to induce angiogenesis?

Cancer cells depend on a large blood supply

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 given locus, homologous chromosomes have

the same genes but can have different alleles

mutations are usually rare, because

DNA polymerase quickly discards 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

which scientist is given credit for proposing the endosymbiont theory?

Lynn Margullis

The nucleotides called pyrimidines include

thymine and cytosine

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

Ordovician

placental mammals appeared during the _______ period

Paleogene

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

Permian

the first energy shell of an atom has on orbital. Therefore, it can contain a maximum of __________ electron(s)

two

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

S phase of interphase