Bio Exam 3

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experts estimate that approximately ______ of the US population (nearly 90 million people) is colonized by S. aureus

30-40%

an individual inheriting the genotype aaBbCc falls in the ____ foot phenotype

5

A mating of two people of medium height (where three genes control height): AaBbCc x AaBbCc produce _____ distinct phenotypes determined by the number of genes inherited.

7

if a person with AB- blood is in need of a transfusion, people with that blood types will be able to donate blood for them

A-

you have type B blood. therefore, you can accept blood donations from people with a

BB and BO genotypes

a wife is heterozygous for DMD alleles and her husband has a dominant allele on his X chromosome. What percentage of their sons and what percentage of their daughters will have DMD

DMD is X-linked recessive. 50 % of their sons will have DMD and 0% of the daughters will have DMD

thich of the steps of bacterial reproduction occurs first

DNA is replicated

If a man has an X-linked recessive disease, can his sons inherit that disease from him? Why or why not?

If a male has an X-linked recessive disease he cannot pass it to his son because the father must pass the Y chromosome to his son. The X chromosome in males will always come from the mother

Why are more males than females affected by X-linked recessive genetic disorders?

Males have only X chromosomes, whereas females have two X chromosomes. Recessive traits occur when only recessive alleles are present. Males have only one allele of each X-linked gene because they have one X chromosome; therefore, if they have the recessive genetic disease. Females are less likely to be affected because their recessive allele can be masked by a dominant allele.

the term "MRSA" as it is used today refers to

S. aureus bacteria that are resistant to many antibiotics

If you are a female, will your brother and your son have essentially identical Y chromosomes?

The brother and son of a female will not have identical Y chromosomes because the Y chromosome is inherited from the father. The exception is if the brother is the son's father

which sex chromosome is present in a typical male

XY

early in development, a human embryo resembles

a car embryo

antibiotics

a chemical that can slow or stop the growth of bacteria; many antibitotics are produced by living organisms

estrogen

a class of sex hormones, including estradiol, that are higher in women than in men and support female sexual development and function

androgens

a class of sex hormones, including testosterone, that are present in higher levels in men and cause male-associated traits like deep voice, growth of facial hair, and defined musculature

which two people would have the most different Y chromosomes

a father and his daughter's biological son

incomplete dominance

a form of inheritance in which heterozygotes have a phenotype that is intermediate between the two homozygotes

codominance

a form of inheritance in which the effects of both alleles are displayed in the phenotype of a heterozygote

population

a group of organisms of the same species living together in the same geographic area

which of these was an adaptation observed in Tiktaalik

a jointed elbow. wrist, and fingerlike bones

which couple could have a boy with Duchenne muscular dystrophy (DMD)?

a male with DMD and a carrier female

which feature of Tiktaalik is not shared with other bony fish

a mobile neck

x-linked traits

a phenotype determined by an allele on an X chromosome

amniocentesis

a procedure that removes fluid surrounding the fetus to obtain and analyze the chromosomal makeup of fetal cells

in the presence of penicillin: what happens to a resistant strain of S. aureus

a resistant strain will not be affected by penicillin and will continue to grow

in the presence of penicillin: what happens to a sensitive strain of S. aureus

a sensitive strain will eventually burst (lyse) and die because of its weakened cell wall

polygenic trait

a trait phenotype is determined by the interaction among alleles of more than one gene

diversifying selection

a type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment

stabalizing selection

a type of natural selection in which organisms with phenotypes at one end of a spectrum are favored by the environment

directional selection

a type of natural selection in which organisms with phenttypes at one end of a spectrum are favored by the environment

pedigree

a visual representation of the occurrence of phenotypes across generations

as a woman ages, the risk of giving birth to a baby with any chromosomal abnormalities increases because

a woman is born with all the eggs she will ever have, all her eggs ages as she ages, older eggs have more chance of acquiring mutations, older eggs have a greater chance of making errors during meiosis

the change in foot structure of horses from ancestral species to modern species is indicative of

adaptation to a prairie environment

when a population shows an adaptation, it means that a population responds to an environmental pressure such that the presence of ____ trait ____ over time

advantageous;increases

if a nondisjunction occurs in meiosis I

all four resulting cells will be aneuploid

what conclusions are drawn from Darwin's proposal of descent with modification, now known as the theory of evolution

all living things are related

a trait with polygenic inheritance is influenced by

alleles of multiple genes

aneuploidies

an abnormal number of one or more chromosomes (either extra or missing copies)

multifactorial

an interaction between genes and the environment that contributes to a phenotype or trait

a person with 47 total chromosomes has a karyotype that can best be described as

aneuploid

chemicals that either kill bacteria or slow their growth by interfering with the function of essential bacterial cell structures are

antibiotics

binary fission is asexual. What does this mean? how could two daughter cells end up with different genomes at the end of one round of binary fission

asexual reproduction involves only one parent. the parent passes on a copy of all its genetic material to its offspring. this means that the offspring are copies of the parent. The two daughter cells that are the products of binary fission could be genetically different if a mutation occurred during replication of the parent genome before division. One copy of the genome would contain the mutation and one copy would not, and each daughter cell would inherit one of the two different copies

In what sense do bacteria "eveolve faster" than other species

because bacteria divide very rapidly, they have a very short generation time. As evolution is a change in allele frequency over time, it doesn't take long for bacterial populations to accumulate many generations. As there is a chance of one or more mutations to arise with every generation, there is a wealth of genetic diversity for natural selection to act on

MRSA is most likely to be problematic of found in the

bloodstream

in codominance wha tphenotype does heterozygotes display

both the homozygous dominants and homozygous recessive phenotypes

how do b-lactam antibiotics kill sensitive bacteria

by destabalizing the cell wall

how do beta-lactam antibiotics kill sensitive bacteria

by destabilizing the cell wall

what are the two major mechanisms by which bacterial populations generate genetic diversity

by gene exchange and mutation

evolution

change in allele frequencies in a population over time

amniocentesis can detect

chromosome abnormalities in the fetus

A black dog is bred with a brown dog, and all the puppies have patches of black and brown. The color coat alleles for black and brown are an example of

codominance

a form of inheritance in which both alleles contribute equally to the phenotype is

codominance

if you carry staph of any strain but aren't sick, you are

colonized

which step is not involved in bacterial reproduction

daughter cells stay attached

natural selection

differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies in a population over tome

a sensitive S. aureua bacterium acquires acquires a new genre that allows it to resist the effects of beta-lactam antibiotics. what might the protein encoded by that gene do

digest beta-lactam antibiotics

the evolution of antibiotic resistance is an example of

directional selection

a woman is born with the BRCA1 breast cancer susceptibility allele. This is a "strike" against her in terms of her risk of developing breast cancer. Which of these will reduce her risk

eating a healthy diet, exercising, and not becoming obese

a highly resistant antibiotic strain of S. aureus would reproduce

equally in the presence or absence of antibiotic

the discovery of transitional fossils is important because it supports

evolution and natural selection

a person with type B blood makes antibodies against the "B" anitgen

false

methicillin is currently used to treat staph infections

false

what are the two major mechanisms by which bacterial populations generate gentic diversity

gene transfer and mutation

When looking at a karyotype, for example to diagnose Trisomy 21 in a fetus, is it possible to use that anlysis also tot ell if the fetus has inherited a cystic fibrosis allele from a carrier mother

genotypes cannot be deduced from karyotype analysis. Karyotype analysis is used to determine the number of chromosomes present

trisomy 21

having an extra copy of chromosome 21; Down Syndrome

what is one human system that protects us from most infections

immune system

for incomplete dominance, what is the phenotype of heterozygotes

in between homozygous dominants and homozygous recessive

what is the difference betweena n S. aureua colonization and an S. aureus infection

in colonization, the bacteria are growing on or in the body without causing disease. infections are associated with disease

how does incomplete dominance differ from co-dominance

incomplete dominance describes traits in which heterozygous individuals have an intermediate phenotype between that if the homozygous dominant and homozygous recessive phenotypes. Traits that are co-dominant produce heterozygotes that display both the dominant and recessive phenotypes. traits that are co-dominant produce heterozygotes that display both the dominant and recessive phenotypes

if you have a genetic predisposition to a disease such as cancer, you will eventually get cancer. Is this a true statement?

it is not necessarily true; it may be dependent on the environment

some of the middle ear bones of humans are homologous with the

jaw bones of reptiles

which inheritance patterns includes an environmental contribution

multifactorial

two people with the same genotype for a condition such as asthma have different phenotypes. this results from what type of inheritance pattern?

multifactorial inheritance

differential survival and reproduction of individuals in response to environmental pressure that leads to changes in allele frequencies in a population over time is called

natural selection

the most severe disease that can result from MRSA is

necrotizing fascitis

If we take the most fit bacterium from one environment--one in which the antibiotic amoxicillin is abundant, for example--and place it in an environment in which a different antibiotic is abundant, will it retain its high degree of fitness?

not necessarily, fitness depends on the ability of an organism to survive and reproduce, and it may not do this as well in a different environment

which hypothetical antibiotic would treat bacterial infections by interfering with bacterial reproduction

oe that decreases cell membrane synthesis

In sedimentary rock, the _____ fossils tend to be found _______

older; in the deeper layers

autosomes

paired chromosomes present in both males and females; all chromosomes except the X and Y chromosomes

sex chromosomes

paired chromosomes that differ between males and females. Females have XX and males have XY

beta-lactam include

penicillin, cephalosporins and methicillin

fitness is determined by the interaction between ____ and the environment

phenotype

the combination of alleles a person inherits predicts a distinct phenotype. we call this type of inheritance

polygenic

a group of organisms of the same species living together in the same geographic are is called a

population

the us of radioactive isotopes as a easure to determine the age of rock or fossils is termed

radiometric dating

a wife is heterozygous for DMD alleles and her husband has a dominant allele on his X chromosome. What percentage of their sons and what percentage of their daughters will have an X-linked dominant form of rickets

rickets is X-linked dominant. 50% of their sons will have rickets and 100% of the daughters will have rickets

which of these is a harmful bacterium

salmonella

people with depression have lower levels of ____ in their brain

serotonin

gonads

sex organs: ovaries in females, testes in males

X-linked traits are most typically inherited by _____ from their _______

sons; mothers

in humans, very large birth weight and very tiny babies do not survive as well as midrange babies. What kind of selection is acting on human birth weight

stabalizing selection

MRSA and drug-resistant syaph refer to

staph strains that are resistant to penicillins, cephalosporins, and beta-lactams

MRSA is caused by a drug-resistant form of

staphylococcus aureus

what is the evolutionary meaning of the term "fitness"

the ability of an individual to survive and reproduce in a given environment. Individuals that are more fit leave more offspring and more of their alleles in the next generation relative to individuals that are less fit

Which of the following most infuence the development of a female fetus?

the absence of a Y chromosome

If you are male, will your brother and your son have essentially identical Y chromosomes?

the brother and son of a male will have essentially identical Y chromosomes because the Y chromosomes is inherited from the father. The two brothers will have received essentially the same Y chromosome from their father and then pass that Y chromosome to their sons

karyotype

the chromosomal makeup of cells. analysis can be used to detect chromosome disorders prenatally

Y-chromosome analysis

the comparison of sequences on the Y chromosomes of different individuals to examine paternity and paternal ancestry

when amniotic fluid is tested for chromosome anaylsis, whose karyotype is being examined

the embryo's

nondisjunction

the failure of chromosomes to separate accurately during cell division; nondisjunction in meiosis leads to aneuploid gametes

If you are blood type A+, to whom can you safely donate blood? who can safely donate blood to you?

the only possible recipient for an A+ door is type A+. The possible donors to an A+ patient are types A+, A-, O+, and O-

what is the environmental pressure in the case of antibiotic resistance

the presence or absence of antibiotics in the environment

gene transfer

the process by which bacteria can exchange segments of DNA between them

adaptation

the process by which populations become beteer suited to their environment as a result of natural selection

which of these is decreased when there is stabalising selection

the range of phenotypic variation

fitness

the relative ability of an organism to survive and reproduce in a particular environment

a male has a son and a daughter. both the son and the daughter have one son and one daughter. which grandchild has a Y chromosome that is identical to the grandfather in this question

the son's son

why do the beta-lactam antibiotics affect sensitive bacterial cells but not eukaryotic cells

they interfere with the syntheis of peptidoglycan-containing cell walls. Humans (and other animals) do not have cell walls at all, and while plant cells do have a cell wall, it is made if cellulose and not peptidoglycan. Eukaryotic cells therefore do not have the structure that is the target of penicillin (and other beta-lactam antibiotics)

an organism's fitness depends on its environment

true

even though mutation rates for bacteria and humans are identical, bacteria are able to adapt more quickly to their environment than are humans

true

binary fission

type of asexual reproduction in which one parental cell divides into two

which situation puts a healthy person at greater risk for a MRSA infection

undergoing a medical procedure that weakens the immune system, undergoing a procedure that causes a break in the skin, being a child whose immune system is still maturing, and being elderly

continuous vatiation

variation in a population showing an unbroken range of phenotypes rather than discrete categories

a homologous structure is one that

was inherited from a common ancesotr

tracing a paternal (male) line of ancestry is best accomplished by examining genes on the ___ chromosome

y

can S. aureus be present in or on a person who has no evidence of an infection

yes; S. aureus is a common skin bacterium


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