OpenStax bio questions exam 1

You have neen identifying the sequence of a segment of a protein. The sequence to date is: Leucine-methionine-tyrosine-alanine-glutamine-lysine-glutamate. You insert arginine between the leucine and methionine. What effect would this have on the segment?

Inserting arginine places a positively charged amino acid in a portion that is non-polar, creating the possibility of a hydrogen bond in this area

Vegans are people who do not consume any animal products in their diet. Why do vegans need to pay special attention to the protein they eat?

It is more difficult to obtain all essential amino acids from single plant sources

K-41 is one of the naturally occurring isotopes of potassium. Use the period table to explain how the structure of K-41 differs from the normal K atom

K-41 has a total of 22 neutrons and normal K atom has 20 neutrons

What part of cell membranes gives flexibility to the structure?

Lipids

What are three functions that lipids serve in plants and/or animals?

Lipids serve in the storage of energy, as a structural component of hormones, and also as signaling molecules.

What are the differences in the way lipids are found or function in plants and animals?

Plants store starch and do not have bile salts whereas animals store triglycerides and have bile salts

Which categories of amino acid would you expect to find on the surface of a soluble protein, and which would you expect to find in the interior?

Polar and charged amino acids will be found in the interior

What categories of amino acids would you expect to find on the surface of a soluble protein and which would you expect to find in the interior? Which of these are some examples for each part of the answer?

Polar and charged amino acids will be found on the surface whereas non-polar in the interior

The word Hydrolysis is defined as the lysis of water. How does this apply to polymers?

Polymers break by separating water into hydrogen and hydroxyl group that are added to the monomers.

Which of the following is not an extracellular matrix role of carbohydrates?

Provide energy for muscle movement

What is the difference between saturated and unsaturated fats?

Saturated fats are SOLID at room temp and unsaturated fats are LIQUID at room temp

Animals cannot digest cellulose due to the type of bonding between the glucose monomers. The glucose monomers are there for an energy source but an unattainable. Yet ruminants such as cows and sheep, and termites eat cellulose in the form of grasses and wood. How do they do it?

Specialized bacteria and protist are found in the digestive tracts of these animals making cellulase that result in cellulose breakdown

Which of these describe some of the similarities and differences between glycogen and starch?

Starch is less branched than glycogen and is found in plants

A mutation occurs and cytosine is replaced with adenine. What impact do you think this will have on the DNA structure?

The DNA will bulge in the places where cytosine is replaced by adenine

Fiber is not really a nutrient, because is passes through our body undigested. Why can't fiber be digested and why is it important to our diet?

The enzymes required to digest cellulose are not produced in human body undigested fiber adds bulk to the food easing bowel movements.

Dehydration is a word usually used to mean the removal of water. How does this apply to macromolecules?

The hydroxyl groups of two monomers are used to form a bond by removing a hydrogen from one monomer and a hydroxyl group from the second forming a molecule to water.

List the mass number and atomic number of Carbon-12 and Carbon-13, respectively

The mass number and atomic number of carbon -13 is 13 and 6, while that of carbon-12 is 12 and 6, respectively

What scientific evidence was used by Carl Woese to determine there should be a separate domain for archaea?

a sequence of RNA

(backwards) Elements of group 1 needs to lose one electron, elements of group 14 need to gain 4 electrons, and elements of group 17 need to gain 1 electron

an atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. Looking at this figure, how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?

Water takes up 333 million cubic miles on Earth, yet access to drinking water is critical issues for many communities around the world. Explain why this is so

only 4% of the total water on earth is freshwater, out of which is 68% is found in glaciers.

What are the 4 types and functions of RNA?

-mRNA: (messenger) is a single stranded transcript of DNA. -rRNA (Ribosomal) is found in ribosomes. -tRNA (transfer) transfers specific amino acids to a developing protein strand -miRNA (micro) regulates the expression of mRNA strands

Which of the following domains contain prokaryotes? 1) Archaea 2) Bacteria 3) Eukarya

1 and 2 (Archaea and bacteria)

Which of the following statements is the strongest argument in favor of two organisms, A and B, being closely related evolutionarily? 1) A and B look alike 2) A and B live in the same ecosystem 3) A and B use the same metabolic pathways 4) The DNA sequences of A and B are highly homologous

4

What is structurally different between starch and cellulose that gives them different physical properties?

Cellulose is formed by B(beta)-1, 4 glycosidic linkages and crosslinks, making it rigid. Starch has a(alpha)-1.4 and 1(alpha) 1.6 glycosicid linkages without the tight crosslinks of cellulose

How does chaperone work with proteins?

Chaperones assist proteins in folding

The protein sequence of cytochrome C from Chimpanzees and humans is identical. The protein sequence of cytochrome C from rhesus monkeys differs from the human sequence by one amino acid. What do these comparisons suggest?

Chimpanzees are more closely related to humans than rhesus monkeys

Carbohydrates serve various functions in different animals. Arthropods like insects, crustaceans, and others, have an outer layer, called the exoskeleton is made mostly of chitin. Chitin is also a major component of the cell walls of fungi, the kingdom that includes molds and mushrooms. Chitin is a polysaccharide. What is the major difference between chitin and other types of polysaccharides?

Chitin is a nitrogen-containing polysaccharide, with repeating units of N-acetyl-B(beta)-D-glucosamine, a modified sugar

What type of compound functions in hormone production, contributes to membrane flexibility, and is the starting molecule for bile salts?

Cholesterol, which is a lipid and also a steroid, functions here.

Why can some insects walk on water?

Insects can walk on water because of its high surface tension

Discuss how buffers help prevent drastic swings in pH

Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decreases in pH. An example is the bicarbonate system in human body

what property of carboxyl containing moles hydrophilic? Which macromolecules contain carboxyl?

-Carboxyl groups realize H+ making its parent molecule hydrophilic -It is found in amino acids and fatty acids

What are two topics that are likely to be studies by biologist and two areas of scientific study that would fall outside the realm of biology?

-Diseases affecting humans, pollution affecting species habitat -Calculating surface area of rectangular ground, functioning of planetary orbitals

In which domain would a fish be classified? Why?

-Eukarya -Because fish are multicellular (eukaryotic)

Compare and contrast saturated and unsaturated fats

-Saturated fats contain single bonds and are solids at room temp -unsaturated fats contain double bonds and are liquids at room temp

Which of the following bodily process would most likely be hindered by lack of water in the body? 1) Digestion 2) protein synthesis 3) Copying DNA d) Breathing

1) Digestion (Digestion involves chemically breaking down larger polymers within food into smaller molecules. Hydrolysis is a process that breaks down molecules. An inability to perform hydrolysis would negativity affect digestion)

What are the 4 classes of lipids and what is an example of each?

1) Lipids--margarine 2) Wax-- like coating on feathers 3) Phospholipids-- like cell membrane constitutents 4) Steroid-- like cholesterol

Which example most clearly shows a way that humans can respond directly to a change in the environment? 1) We shiver when we are cold and swear when we are hot 2) We walk by putting our front leg forward and pushing off with out back leg 3) we are able to breath in and out unconsciously 4) Our hair and fingernails grow at a constant rate over time

1) We shiver when we are cold and sweat when we are hot

Which of the following statements is FALSE? 1) Tissues exist within organs which exist within organ systems 2) Communities exist within populations which exist within ecosystems 3)Organelles exist within cells which exist within tissues 4) Communities exist within ecosystems which exist in the biosphere

2

Which of the following structures is conserved in all living organisms and points to a common origin? 1) All living organisms have mitochondria that produce energy 2) All living organisms store genetic material in DNA/RNA 3)All living organisms use the energy from sunlight 4) All living organisms have a nucleus

2) All living organisms store genetic material in DNA/RNA

Limestone is naturally occurring mineral rich in calcium carbonate (CaCO3). In water, calcium carbonate dissolves to form carbonate (CO32-), a weak base that acts as a buffer. Which would you expect to be more affected by acid rain, an environment in rich limestone or an environment poor in limestone?

An environment poor in limestone would be more affected by acid rain

Most organisms carry their hereditary genetic information as DNA. However, some viruses use RNA instead. The HIV virus has RNA, but its genetic information is found in host DNA. How does this happen?

An enzyme reverses the usual process, producing DNA from the viral RNA

The French scientist Jacques Monod famously said "Anything found to be true of E. Coli must also be true of elephants." How is this statement based on the notion that living organisms share a common ancestor?

E. Coli is a prokaryote. The various metabolic processes and core functions in E. Coli share homology with higher organisms.

Describe the pH scale and how it relates to living systems. Give an example of how drastic pH changes are prevented in living systems.

The pH scale ranges from 0 to 14, where anything below 7 is acidic and above 7 is alkaline. The bicarbonate system in the human body buffers the blood

How do phospholipids contribute flexibility to cell membrane structure?

The phospholipids containing unsaturated fatty acids cannot be tightly packed which provides membrane flexibility.

What is the importance of the nodes seen on the illustration of the phylogenetic tree seen?

They show points during evolution when ancestors are believed to have broken off into two new species

When the temperature of liquid water is reduce, water freezes and becomes less dense. This is a property not seen in most other liquids. Ice floats on liquid water because it is less dense. What molecular property of water allows for this phenomenon?

When water cools, hydrogen bonds form, pushing water molecules apart into a regular crystal structure.

The unique properties of water are important in biological processes. For the following three properties of water define the property and give one example of how the property affects living organisms: 1) Cohesion 2) Adhesion 3) High heat vaporization

cohesion is the attraction between the water molecules, which helps create surface tension. Insects can walk on water because of cohesion. adhesion is the attraction between water molecules another molecules. Water moving up from the roots of plants to the leaves as a result of capillary action is because of adhesion. Heat vaporization is the amount of energy required to convert liquid into gas. This property helps humans maintain homeostasis of body temperature of evaporation.

How do the differences in amino acid sequences lead to different protein functios?

different amino acids produce different proteins based on the bonds formed between them

What molecule carries information in a form that is inherited from one generation to another?

hereditary information is stored in DNA

Why can water be a good insulator within the body of endothermic (water-blooded) animals?

specific heat capacity

What best describes the production of sucrose, maltose, and lactose?

Glucose and fructose combine to form sucrose. Glucose and galactose combine to form lactose. Two glucose monomers combine to form maltose

Identify each sugar as an aldose or ketose 1) Fructose 2) Galactose 3) Glucose

Glucose and galactose are aldoses. Fructose is a ketose

What role do electrons play in dehydration synthesis and hydrolysis?

H+ and OH- ions share electrons with the respective monomers in hydrolysis

How can an unsaturated fat be made to function like a saturated one?

Hydrogen is bubbled through unsaturated fats to form saturated fats and incidentally trans fats

All flying birds and insects have wings. Birds and insects flap their wings as they move through the air. Therefore, wings enable flight. DECUDTIVE OR INDUCTIVE REASONING?

INDUCTIVE

Animals as diverse as insects and wolves all exhibit social behavior. Therefore, social behavior must have an evolutionary advantage for humans. DEDUCTIVE OR INDUCTIVE REASONING?

INDUCTIVE

What makes ionic bonds different from covalent bonds?

Ionic bond involves the TRANSFER of electrons whereas covalent bonds involves the SHARING of electrons

Some plants called lithops grow in South African desert and look like stones. How were scientist able to determine they are living organisms?

Lithops are autotrophic. They show growth and reproduction

(Backwards) Group 1 and group 17

Looking at the figure, can you infer which two groups together will form a strong ionic bond?

(backwards) Carbonyl, methyl, carboxyl

Name the 3 functional groups in the compounded in the picture

How do phospholipids contribute to cell membrane structure?

Phospholipids orient their heads towards the polar molecules and tails in the interior of the membrane, thus forming a bilayer.

Phylogenetic trees can represent traits that are derived or lost due to evolution. One example is the absence of legs in some marine mammals. One such group is the Cetaceans, which includes toothed whales, such as dolphins and killer whales, and baleen whales such as humpback whales. Cetaceans are descended from even-toed ungulates and share a common ancestry with the hippopotamus, cows, sheep, camel, and pig. Based on this phylogenetic tree, which of the following animal is the most closely related to a horse? 1) armadillo 2)camel 3)bat 4)cat

CAT

What property of carbon makes it essential for organ life?

Carbon can form up to 4 covalent bonds, allowing it to form carbon chains

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12 contains neutrons while carbon-13 contains 7 neutrons

The shape of hair proteins is maintained by a combination of hydrogen bonds and covalent, disulfide bonds. Heat is sufficient to break the hydrogen bonds, but harsh chemicals are required to break the disulfide bonds. Why is it harder to break the disulfide bonds than the hydrogen bonds?

Covalent bonds are stronger than hydrogen bonds

Chromosomes, the carriers of the DNA, separate into daughter cells during cell division. Therefore, DNA is the genetic material. DEDUCTIVE OR INDUCTIVE REASONING?

DEDUCTIVE

Insects generally survive mild winters better than harsh ones. Therefore, insects pests will become more problematic if global temperatures increase- DEDUCTIVE OR INDUCTIVE REASONING?

DEDUCTIVE

What are some reasons that DNA is double stranded and RNA is single stranded in plants and animals ?

DNA encodes multiple genes and is stable. RNA is functional and translated into proteins

The word helix means spiral. What does this tell you about the structure of the DNA, which is a double helix macromolecule?

DNA is a double helix because it has two strands held together like a spiral staircase

a change in DNA on a chromosome affects all proteins made from that gene for the life of the cell. A change in the RNA involved in protein production is short lived. What is the difference between the effects of the changed in the two types of nucleic acids?

DNA is passed on to the daughter cell, permanently altering the genetic material

One of the risks for people with diabetic ketoacidosis, a build-up of acid in the blood stream. Explain why this dangerous to humans

Diabetic Ketoacidosis decreases normal pH (7.35-7.45) to a lower value

How do the differences in amino acid sequence lead to different protein functions?

Different amino acids provide different geometric configurations and thus varied functions

Is the statement "To be enantiomers, a molecule must have at least three different atoms or groups to a central carbon" TRUE or FALSE?-- WHY?

FALSE-- Enantiomers are mirror images of each other

Why do long distance runners "carbo load" before a race?

They eat foods high in starch, a polysaccharide, because they can be broken down slowly into monosaccharide to provide long lasting energy

What causes the changes in protein structure through the three or four levels of structure?

The primary chain forms secondary a-helix and B-pleated sheets which fold onto each other forming the tertiary structure

Describe the change in structure through the 3rd and 4th levels of protein structure

The primary polypeptide structure is folded into the secondary structure by hydrogen bonds; amino acid side chain interactions then form the tertiary structure. Sometimes multiple subunits come together to form a quaternary structure. These subunits can be the same or different from one another

Why have trans fats been banned from some restaurants? How are the created?

Trans fat is produced by the hydrogenation of oil that makes is more saturated and isomerized. It increased LDL amounts.

The fatty acids of triglycerides are classified as saturated, unsaturated or trans dats. What is it about the structure of these compounds that distinguishes them from each other?

Trans fats are a type of unsaturated fat where the hydrogen around the double bond are not in the same plane

Using the DNA ATC/GTT/GTA/CTG/TAG/GAT/AAA What mRNA would be made from this DNA fragment?

UAG/CAA/CAU/GAC/AUC/CUA/UUU In forming an mRNA, the adenine pairs with uracil and guanine with cytosine