What are for ways (anatomical or physiological) plants in dry environments conserve water?

Why is a retrovirus like HIV almost invariably capable of evading the host's immune system when many other pathogens are not?

Shown following is the first 30 amino acid (one-letter code) region of this putative amino acid sequence for p18:

¹YFNPS     ^6TSDWPT    ¹¹LAPAN    ¹⁶YTFLF    ²¹FLARY    ²⁶WYINL³⁰

A) Based on the partial amino acid sequence provided, do you think that it is more likely that this region of p18 associates with a cellular membrane or is exposed to the cytosol?

B) Why or why not?  

C) Describe how you would experimentally demonstrate if p18 was associated with the membrane or the cytosol.

Describe a way a drug might affect synaptic transmission.

Describe the role of vesicles in the transport process between the nucleus, endoplasmic reticula, and the golgi apparatus.

Foodborne epidemiologists at the local health department investigated an outbreak of food poisoning at a Cinco de Mayo potluck dinner. Initially the epidemiologists determined that nachos were the cause of the outbreak. However, upon closer review lettuce was determined to be the true cause of the outbreak.

6a. In this example, would you expect lettuce to act as a positive or negative confounder on the relationship between nachos and food poisoning? Explain your answer.

6b. Assume that you want to analyze the association between nachos and food poisoning. Provide a method to control for the confounder lettuce in the design of your study. Please be specific.

Please explain clear and different to the answers that are already in other websites. Thank you

1. An interesting mutation in lacI results in repressors with 110-fold increased binding to both operator and nonoperator DNA. These repressors display a “reverse” induction curve, allowing β-galactosidase synthesis in the absence of an inducer (IPTG) but partly repressing β-galactosidase expression in the presence of IPTG. How can you explain this? (Note that, when IPTG binds a re- pressor, it does not completely destroy operator affinity, but rather it reduces affinity 110-fold. Additionally, as cells divide and new operators are generated by the synthesis of daughter strands, the repressor must find the new operators by searching along the DNA, rapidly binding to nonoperator sequences and dissociating from them.)

2. Certain lacI mutations eliminate operator binding by the Lac repressor but do not affect the aggregation of subunits to make a tetramer, the active form of the re- pressor. These mutations are partly dominant over wild type. Can you explain the partly dominant I− pheno- type of the I−/I+ heterodiploids?

3. You are examining the regulation of the lactose operon in the bacterium Escherichia coli. You isolate seven new inde- pendent mutant strains that lack the products of all three structural genes. You suspect that some of these muta- tions are lacIS mutations and that other mutations are al- terations that prevent the binding of RNA polymerase to the promoter region. Using whatever haploid and partial diploid genotypes that you think are necessary, describe a set of genotypes that will permit you to distinguish be- tween the lacI and lacP classes of uninducible mutations.

A study is conducted on 8,000 individuals free of diabetes and 8,000 individuals with diabetes. The investigators are looking to determine if a newly marketed drug may prevent diabetes. Among patients with diabetes, 1,000 individuals received the new drug. Among patients without diabetes, 2,000 individuals received the drug.

4a. Construct a 2 by 2 table displaying the combination of diabetics/non-diabetics who are exposed/not exposed.

4b. Calculate an odds ratio and provide an interpretation

4c. Calculate the relative risk and provide an interpretation.

4d. If the number of non-diabetic patients was increased to 800,000, would you expect the answers in 2b and 2c to be more or less similar to each other? Explain why.

1. In the absence of folate-fortified foods, is it possible that mutations in the pathway of folate synthesis could cause Spina Bifida?

2. What are the possible advantages or disadvantages to the organism or its offsrping resulting from DNA modification by environmental factor?

Tom was recently diagnosed with a tumor in the posterior aspect of his spinal cord at the level of C6 that has resulted in a C5 incomplete spinal cord injury with changes in sensation. Based on the location of the tumor: 1. What ascending spinal tract(s) have been affected? 2. What types of sensation have been affected and what types remained intact? (i.e. temperature, pain, proprioception, etc.) 3. Where on Tom’s body will the sensory deficits be present? Use specific dermatomes. After Tom undergoes surgery to remove the tumor, he presents to inpatient rehabilitation to begin therapy. 1. Given the sensory changes you discussed above, what activities would be difficult for Tom to perform? (i.e. ADLs, functional mobility…) 2. If you were Tom’s occupational therapist, what interventions would you recommend to help with his recovery

what are the aspects of visual impairment and blindness?

Question 1

What is the process that results in a population adapted to the environment?

Group of answer choices

natural selection

reproduction

homeostasis

biodiversity

metabolism

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Question 2

Which of the following is NOT required for natural selection?

Group of answer choices

Organisms acquire their characteristics under environmental pressure

Organisms struggle to exist

Organisms vary in their traits

Organisms differ in their fitness biodiversity

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Question 3

Match the evidence for evolution with its example. Answers can be used more than once.

Group of answer choices

The human knee bone and spine were derived from ancestral structures that supported four-legged animals.

      [ Choose ]            Anatomical / Biogeographical / Biochemical      

The genetic code is the same for all organisms.

      [ Choose ]            Anatomical / Biogeographical / Biochemical      

The South American continent lacks rabbits, even though the environment is quite suitable.

      [ Choose ]            Anatomical / Biogeographical / Biochemical      

The amino acid sequence of human hemoglobin is more similar to that of rhesus monkeys than to that of mice.

      [ Choose ]            Anatomical / Biogeographical / Biochemical      

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Question 4

The fossil record offers direct evidence for common descent because you can (select all that apply)

Group of answer choices

trace the ancestry of a particular group over time.

sometimes find common ancestors.

see the different beak sizes in finches

see that the types of fossils change over time.

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Question 5

Which of the following is NOT an example of natural selection?

Group of answer choices

On a tree, leaves that grow in the shade are larger than those that row in the sun.

Plant species that produce fragrances to attract pollinators produce more offspring.

Rabbits that sprint quickly are more likely to escape predation.

Insect populations exposed to pesticides become resistant to the chemicals.

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Question 6

The process of ____________ leads to organisms that are ______________ that environment.

Group of answer choices

homeostasis, suited to

natural selection, adapted to

evolution, not suited to

adaptation, only found in

natural selection, perfect for

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Question 7

Which of the following is NOT evidence that supports evolution?

Group of answer choices

Geology and fossils

Analogous structures

Biogeography

Anatomically similar structures

Molecular biology

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Question 8

What 3 factors in the body interact to maintain homeostasis?

Group of answer choices

Proteins, carbohydrates, and lipids

Chemical, thermal and neural factors

Chemical, thermal and endocrine factors

Hormone, immune, and neural factors

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Question 9

Which of the following are examples of things in the body that need to maintain homeostasis (select all that apply)?

Group of answer choices

Body Temperature

Blood Pressure

Skin pigments

Blood Composition

Blood Volume

Digestive enzymes

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Question 10

Placebos are used in which of the following?

Group of answer choices

Independent variable groups

Test groups

Control groups

Dependent variable groups

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Question 11

A hypothesis cannot be formed without a/an

Group of answer choices

observation

conclusion

theory

experiment

data

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Question 12

In an experiment, what is the variable that is measured?

Group of answer choices

Placebo

Dependent

Independent

Control

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Question 13

Which of the following are molecules?  Select all that apply.

Group of answer choices

H2O

NaCl

N2

Mg

CO2

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Question 14

Which of the following are compounds?  Select all that apply.

Group of answer choices

N2

CO2

NaCl

H2O

Mg

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Question 15

Which of the following are ions?  Select all that apply.

Group of answer choices

C

Cl-

K+

Mg

Na

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Question 16

Match the different types of bonds with their example

Group of answer choices

bond formed between two water molecules

      [ Choose ]            hydrogen bond / ionic bond / covalent bond      

bond formed between K+ and Cl-

      [ Choose ]            hydrogen bond / ionic bond         /covalent bond      

bond formed by sharing electrons

      [ Choose ]            hydrogen bond            ionic bond            covalent bond      

bond formed between C and H in methane

      [ Choose ]            hydrogen bond            ionic bond            covalent bond      

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Question 17

The number of electrons in the valance shell determines the reactivity of an atom.

Group of answer choices

True

False

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Question 18

In this equation: 6 CO₂ + 6 H₂0 --->   C₆H₁₂O₆  +  6 O₂, name the reactants:

Group of answer choices

H2O

C6H12O6

C6H12O6 and O2

CO2 and H2O

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Question 19

A sulfur atom has 16 electrons. How many electrons are in its valence shell?

Group of answer choices

16

2

8

6

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Question 20

Match the biochemical building blocks with their role in the cell.

Group of answer choices

Proteins

      [ Choose ]            form membranes / direct cellular activity and synthesis of all cellular proteins. / form internal support and act as enzymes / provide energy and form specialized compounds      

Nucleic acids

      [ Choose ]            form membranes / direct cellular activity and synthesis of all cellular proteins. / form internal support and act as enzymes / provide energy and form specialized compounds      

Carbohydrates

      [ Choose ]            form membranes / direct cellular activity and synthesis of all cellular proteins. / form internal support and act as enzymes / provide energy and form specialized compounds      

Lipids

      [ Choose ]            form membranes / direct cellular activity and synthesis of all cellular proteins. / form internal support and act as enzymes / provide energy and form specialized compounds      

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Question 21

Biological molecules are polymers that are formed when ______ are joined by a ___________reaction.

Group of answer choices

Subunits, reduction

Monomers, hydrolysis

Monomers, dehydration synthesis

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Question 22

Quaternary structure occurs when a protein has

Group of answer choices

Folding and twisting of the secondary structure

More than one polypeptide

Pleated sheets

A sequence of amino acids

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Question 23

What type of reaction is represented in the diagram below?

Group of answer choices

hydrolysis

dehydration synthesis

anabolic

enzymatic

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Question 24

What molecule is represented by the “?” in the diagram below:

Group of answer choices

ATP

alcohol

water

enzymes

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Question 25

The diagram below represents

Group of answer choices

an amino acid

water

monomers

a polymer

glucose

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Question 26

Examples of the diagram below include (select all that apply)

Group of answer choices

starch

amino acids

proteins

fatty acids

glucose

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Question 27

The diagram below represents

Group of answer choices

proteins

water

RNA

a polymer

monomers

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Question 28

Examples of the diagram below include (select all that apply)

Group of answer choices

glucose

protein

amino acids

fatty acids

starch