tutorials 1, 2, 3

PART B Which of the following is not attached to the central carbon atom in an amino acid?

An oxygen

PART A Complete the following vocabulary exercise relating to the level of structure in proteins.

1. tertiary 2. primary 3. quaternary 4. secondary

PART A If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand?

3'-TAAACG-5'

Approximately how far back in time does the fossil record extend?

3,500,000,000 years

PART F -- interpreting the data Approximately when did Neanderthals become extinct at this location, according to the study?

40,110 years ago or less

PART E Using the 14C calibration on the x-axis, what is the approximate age of the Neanderthal fossil?

40,110 years old

PART D -- using data from the graph Approximately how many half-lives have passed since the Neanderthal died?

7 half-lives

PART B If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?

75

PART E Which of these bonds is weakest?

A. photo of hydrogen bond

PART E Which of the following statements about the formation of polypeptides from amino acids is true?

A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.

PART E Which of these images shows the correct orientation of phospholipids in a biological membrane?

B

If two molecules of glucose (C6H12O6) are joined via condensation synthesis, the resulting molecule would have a molecular formula of _____.

C12H22O11

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18H32O16

Which of the following hydrocarbons has a double bond in its carbon skeleton?

C2H4

PART C Which part of an amino acid is always acidic?

Carboxyl functional group

PART C Which of these is a phospholipid?

E

Which of the following is true of natural selection?

It requires genetic variation, results in descent with modification, and involves differential reproductive success.

There are four levels of protein structure. These figures show primary, secondary, tertiary, and quaternary protein structure. Which level(s) of protein structure may be stabilized by covalent bonds?

Primary, tertiary and quaternary levels of protein structure

PART H -- dating other fossils Most dinosaurs went extinct 65.5 million years ago. Can 14C be used to date dinosaur bones?

No, the 14C present in the dinosaur when it died would decay too much to be measured after 65.5 million years.

PART F Why isn't this insect drowning?

Surface tension

PART A Glycogen is _____.

a polysaccharide found in animals

The available scientific data indicates that life first arose _____.

about 3.7 billion years ago

In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits ________.

altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered

Which of these individuals is likely to be most successful in an evolutionary sense?

an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce

PART E A function of cholesterol that does not harm health is its role _____.

as a component of animal cell membranes

Which of the following is a major difference between RNA and DNA?

type of sugar

RNA's nitrogenous bases include _____.

uracil and guanine

An example of catabolism is the _____.

breakdown of starch into simple sugars

The large diversity of shapes of biological molecules is possible because of the extensive presence of _____ in the molecules.

carbon

In the case study for Tutorial #2, you learned about the "Evolution Canyons" that are found in a mountain chain in Israel. Singaravelan et al (2010) investigated how the melanin content of the hair of spiny mice (Acomys cahirinus) has evolved in response to the selection pressures of the different environments of the north and south-facing slopes of Evolution Canyon I (ECI). The results of this study show that spiny mice that live on the south-facing slope of ECI have _____.

higher pheomelanin than eumelanin content in their hair

Lipids are predominantly hydrophobic because of their _____.

hydrocarbon chains

PART C The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.

hydrogen bonds

Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as ______.

hydrogen bonds

PART C What holds phospholipids together in a bilayer formation?

hydrophilic and hydrophobic interactions with water

PART B glucose + glucose —> _____ by _____

maltose + water ... dehydration synthesis

PART C Which of these is a source of lactose?

milk

Which of these provides evidence of the common ancestry of all life?

near universality of the genetic code

PART D Which monomers make up RNA?

nucleotides

The building blocks or monomers of nucleic acid molecules are called _____.

nucleotides

PART D A nucleotide is composed of a(n) _____.

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

PART B What functional feature(s) does the phosphate group contribute to the structure of a phospholipid?

place to attach another small charged molecule; negative charge to interact with water

PART B The unequal sharing of electrons within a water molecule makes the water molecule _____.

polar

PART D In this molecule, what type of bond is found between the oxygen and hydrogens?

polar covalent

PART B Sort the images according to the level of structure in the proteins shown.

primary -- sequence of proteins secondary -- sequence begins to fold tertiary -- smaller coiled quaternary -- larger foiled

PART B Arrow D is indicating a _____ protein.

receptor

PART B This figure is an example of a(n) _____.

saturated fat

_____ is(are) the best source of fossils.

sedimentary rock

All of the following are functions of proteins EXCEPT _____.

storage of genetic information

PART A Arrow A is indicating a(n) _____ protein.

structural

"A" is ______; "B" is ______.

the common ancestor of all life; the last common ancestor of Archaea and Eukarya

Radiocarbon dating is appropriate to use when estimating the dates of fossils deposited at the time of _____.

the first European occupation of the New World (less than 10,000 years ago)

PART F True or false? Enzymes in the digestive tract catalyze hydrolysis reactions.

true

PART C The tendency of an atom to pull electrons toward itself is referred to as its _____.

electronegativity

How many half-lives should have elapsed if 6.25% of the parent isotope remains in a fossil at the time of analysis?

four

PART A A water molecule can bond to up to _____ other water molecules by _____ bonds.

four ... hydrogen

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16) Hemoglobin, when subjected to 40% acetonitrile at pH 10.0, loses its quaternary structure, which means the ________.

four α and β polypeptides dissociate

PART C Which of these does NOT contain a structural protein?

ovalbumin

According to the evidence for the early chemical evolution of life, the atmosphere on early Earth was highly reductive because it was lacking which of the following key molecules?

oxygen

PART B The graph below is the same as in Part A, but with the fractions converted to decimal values. For each decimal value, fill in the exponent to complete the scientific notation. Don't forget to indicate if the exponent should be negative (-).

(top to bottom) -1, -1, -2, -2, -2, -3, -3, -3, -4

PART A -- reading the graph Drag the fractions to indicate the amount of isotope remaining at each point in time.

(left to right) 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, 1/256, 1/512, 1/1024

If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old?

22,900

You are an archaeologist who has just found an ancient fire ring containing charcoal fragments. You send these fragments to the lab for carbon-14 analysis. The report comes back that these fragments have 1/4 the amount of carbon-14, compared to modern wood. You use 5730 years as the half-life of carbon-14. You conclude the charcoal is about _____.

11,460 years old

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16) How many heme groups are present in three hemoglobin protein molecules?

12

The available astronomical data indicate that the universe is about _____.

13 billion years old

PART C -- Calibrating the graph to 14C decay To calibrate the x-axis for 14C decay, you have to convert half-lives to number of years. Recall that 14C has a single half-life of 5,730 years. How many years make up 5 half-lives for 14C?

28,650 years

How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?

19

PART A How many fatty acids are in a phospholipid?

2

There are _____ amino acids that are used by organisms for protein synthesis.

20

PART D Which molecule is less soluble in water--a fat or a phospholipid? Why?

A fat molecule is less soluble in water because it has three non-polar fatty acids and no polar or charged head like a phospholipid has.

You find an ancient spear and apply dendrochronological methodology to discover that its growth ring pattern corresponds to 5,000 years ago. You are not satisfied with this single method and want to corroborate the date using another approach. You turn to carbon-14 methodology. If the dendrochronology data are correct, how much carbon-14 (compared to modern wood) should be present in the spear?

About 50%

PART E _____ is the most abundant organic compound on Earth.

Cellulose

What is metacognition?

Metacognition is an awareness and understanding of one's own thought processes while actively monitoring one's own learning and making changes to one's own learning behaviours and strategies based on this monitoring.

Which of the following statements about natural selection is most accurate?

Natural selection can only act on populations with genetic variation.

PART G What does this suggest about the possible overlap of Neanderthals and modern humans in the region?

Neanderthals and modern humans may have lived in the same region for up to approximately 2,000 years, or they may not have overlapped at all.

Carbon-14 decays into _____.

Nitrogen-14

PART A Which polymers are composed of amino acids?

Proteins

These figures show the four levels of protein structure: primary, secondary, tertiary, and quaternary structure. Which level of protein structure is characteristic of some, but not all, proteins?

Quaternary level of protein structure

If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?

RNA

PART A Which of these is NOT a lipid?

RNA

PART I Radioactive uranium-235 has a half-life of 704 million years. If it was incorporated into dinosaur bones, could it be used to date the dinosaur fossils?

Yes, after 65.5 million years only about one tenth of the 235U would have decayed, leaving plenty to measure in the fossils.

You are suffering from Streptococcus throat infection. You share the following with the bacteria that is responsible for your condition.

You both are made up of cells.

"The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16) Hemoglobin is ________.

a quaternary protein with four polypeptides

PART D Which of these is a polysaccharide?

cellulose

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should _____.

determine if hair length is heritable

PART D Defensive proteins are manufactured by the _____ system.

immune

Natural selection _____.

is the process by which a population becomes more well adapted to its' environment over time

PART D Which of these is rich in unsaturated fats?

olive oil

The diversity of carbon compounds is largely due to carbon's _____.

valence of four