Bio test 1

It is actually the component of a 30S ribosomal subunit that is responsible for recognition of a Shine- Dalgarno sequence on an mRNA. Which one of the sequences in the 16S rRNA would you predict is responsible for the interaction between a small subunit and MRNA? 5'-UGGAGGA-3' 3-UAC-5' 5'-AGGAGGU-3' 5'-UCCUCCA-3' 3'-UCCUCCA-5'

3'-UCCUCCA-5'

If humans never existed on earth which organism would likely still be found? All of these choices are correct Cockroaches Wheat Passenger pigeons Rats

All

In the twenty first century, humans have become major agents in ecology and evolution. The actions of humans: include curing diseases. have driven and are driving a variety of plant and animal species to extinction. have altered the carbon dioxide levels in the atmosphere. All of these choices are correct. can be felt in almost every facet of life, positively or negatively.

All

Rickettsia typhi is a species of infectious bacterium that is an obligatory intracellular parasite. This means that, similar to viruses, R. typhi cannot reproduce and survive outside of a eukaryotic cell. Why do we consider viruses nonliving, but rickettsia alive? R. typhi synthesizes its own proteins; viruses use the cell machinery for protein synthesis. R. typhi has both DNA and RNA; viruses have either one, or the other, but not both. All of these choices are correct. R. typhi has an active membrane; viruses are surrounded by protein coat.

All

Folding domains show how structure relates to function because: they create regions whose shape and charge can bind specific smallmolecules. they create surfaces whose shape and charge allows them to interact with other folding domains. All of these choices are correct. they change the configuration of the polypeptide in such a way as to facilitate proper folding of other regions.

All of these choices are correct.

Which of the events is a possible function of a protein-folding domain? All of these choices are correct. facilitation of interactions between proteins catalysis transport of molecules across a membrane

All of these choices are correct.

Which statement is true regarding the development of pyrimethamine resistance in malaria parasites? Rare mutations in the target protein increased the level of resistance. Eventually, the drug pyrimethamine became ineffective against malaria. In time, multiple different mutajons were brought together to increase the level of resistance. Continued use of pyrimethamine treatment caused these mutations to increase in frequency. All of these choices are correct.

All of these choices are correct.

Imagine that a scientist is able to travel back in time to when the first proteins appeared. What would she observe? All proteins would be relatively short. Proteins would have relatively complex folding domains. Proteins would possess several folding domains. Proteins would be long compared to proteins today. None of these choices is correct.

All proteins would be relatively short.

Which one of the statements about translation in eukaryotes is correct? Translation continues until the ribosome comes to the end of mRNA. There is an untranslated region only at the 3' end of mature mRNA. A single mRNA can possess multiple protein coding regions. An initiation complex recognizes a 5' cap structure and scans for the first AUG triplet. All of these choices are correct.

An initiation complex recognizes a 5' cap structure and scans for the first AUG triplet.

What unique property of carbon enables this element to be "life's chemical backbone"? Carbon behaves as if it has four valence electrons. Carbon has four electrons. Carbon can form double bonds. Carbon is the most abundant element in the universe. Carbon can form double or single bonds.

Carbon behaves as if it has four valence electrons.

The feature of an experiment that is not changed from one treatment to the next is referred to as an Observation Control Variable Test group

Control

Which one of the amino acids is capable of forming a disulfide linkage with itself? methionine cysteine isoleucine tyrosine arginine

Cysteine

The study of how organisms interact with each other and with their physical environment is referred to as Physiology Behavior Evolution Ecology

Ecology

The cell theory states that all living organisms are composed from cells and that new cells can only arise from existing cells. Which statement supports the cell theory? Cells can spontaneously arise from water and nutrients. Bacteria do not have mitochondria and, therefore are not real cells. Human erythrocytes do not have nuclei and, therefore, are not real cells. Embryonic cells undergo mitotic division.

Embryonic cells undergo mitotic division.

There are many different types of bacteria able to grow in a human host, and they are all disease-causing organisms True False

False

There is approximately the same number of proteins families as there are folding domains True False

False

Which of the statements is true regarding glycine? Glycine increases the flexibility of the peptide backbone. Glycine is a large, polar amino acid. Glycine is special because it contains a -SH group important in protein folding. Glycine is similar to tyrosine in terms of structure and chemical properties. Glycine is an asymmetric amino acid.

Glycine increases the flexibility of the peptide backbone.

In Pasteur's experiment showing that living microorganisms arise from other living microorganisms, which statement describes Pasteur's hypothesis? The first cells must have come from chemical reactions occurring in early Earth. Microbes should be capable of growing equally well in sterile broth contained in both straight- neck and swan-neck flasks. If microbes arise from nonliving matter, they should appear spontaneously in both sterile and nonsterile broth. Straight-neck flasks should allow for more contamination than swan-neck flasks. Sterilization of broth kills microbes.

If microbes arise from nonliving matter, they should appear spontaneously in both sterile and nonsterile broth.

Which statement is true regarding primary transcripts? In eukaryotes, primary transcripts are polycistronic. In prokaryotes, primary transcripts undergo polyadenylation and alternative splicing. In both eukaryotes and prokaryotes, introns are removed from the primary transcripts. In eukaryotes, a primary transcript can be transcribed and translated at the same time. In prokaryotes, primary transcripts are synonymous with MRNA.

In prokaryotes, primary transcripts are synonymous with MRNA.

Which statement represents the flow of information as described by the central dogma of molecular biology? Information in DNA is transcribed into protein, which carries the information to make RNA. Information in protein is transcribed into RNA and then stored as DNA. Information in RNA is transcribed into DNA and then protein is made directly from the DNA. Information in DNA is transcribed into RNA, which carries the information to make protein. Information in DNA can be directly translated into protein. RNA is not always required for protein production.

Information in DNA is transcribed into RNA, which carries the information to make protein.

Which statement regarding plants is (are) true? Plants evolved independently without interactions with other organisms Unlike animal life plant life does not require carbon Plants only produce nectar for the benefit of insects All of these choices are correct Many plants can reproduce both sexually and asexually

Many plants can reproduce both sexually and asexually

Imagine that you are looking at the tree of life. The majority of branches on this diagram would represent which type of organisms Microbes Plants Humans Mammals Viruses

Microbes

One of your friends has decided to make it his life's work to characterize all functional proteins, as he is convinced that all possible amino acid combinations can result in a protein. Is it possible to confirm his hypothesis in this way? Yes, because all possible amino acid combinations result in proteins, although many of these proteins have nearly identical structures. No, because most amino acid sequences cannot produce functional proteins. Yes, because most amino acid sequences actually produce functional proteins; however, many of these proteins are degraded in cells. No, because even though all sequence combinations can result in functional proteins, it would be impossible to characterize all of them.

No, because even though all sequence combinations can result in functional proteins, it would be impossible to characterize all of them.

You have learned that mutations can occur in DNA sequences. Are all mutations deadly No, some mutations can have no effect or can be beneficial. Yes, all mutations are deadly No, All mutations are benign Yes, because all mutations in DNA disrupt the central dogma

No, some mutations can have no effect or can be beneficial.

Based on the characteristics of living organisms, which thing would not be considered alive? plants and bacteria a bacterium,which is a relatively "simple" organism a plant, which is unable to move when the weather changes a spayed cat, which is unable to reproduce None of the other answer options is correct.

None of the other answer options is correct

Which element is found in nonliving systems but not found in more than trace amounts in systems? Calcium Silicon Hydrogen Carbon Oxygen

Silicon

Which of the statements about amino acids is correct? Every amino acid is asymmetric. The bridge between cysteines, which connects parts'of a protein, is a stable covalent interaction. A turn or kink in a protein is more likely to be induced by a glycine than by a proline. The more asparagines thaare found in a polypeptide's primary sequence, the more flexible the backbone of that polypeptide. At typical cellular pH, the R groups of basic amino acids are negatively charged.

The bridge between cysteines, which connects parts'of a protein, is a stable covalent interaction.

The strongest evidence that a meteor impact is associated with dinosaurs becoming extinct is provided by: Contamination of fossils from that time period with fragments of rock that penetrated the skeletons of many dinosaurs The presence of significant levels of iridium in the rock layers corresponding to the time of dinosaur extinction High levels of particulate matter in the lungs of dinosaur specimens perfectly preserved in ice. The detection of High levels of radioactivity in the fossilized remains of dinosaurs from the time period corresponding to extinction

The presence of significant levels of iridium in the rock layers corresponding to the time of dinosaur extinction

A general explanation of an aspect of the world, supported by a large body of experiments and observations, is called a(n): observation. hypothesis. experiment. theory.

Theory

You have discovered a new species of prokaryote in a deep-sea thermal vent. Without any further characterization, which statement could you make about this species with a high degree of certainty? The organisms are from the domain Archåea. None of the statements can be made with a high degree of certainty. Information in DNA is translated into RNA and then transcribed into protein. These organisms store their genetic information as DNA. Information in RNA is transcribed into DNA and then translated into protein.

These organisms store their genetic information as DNA.

An operon is a group of functionally related genes transcribed as a polycistronic MRNA from a single promoter to a single terminator. true false

True

Introduction of high-yield, disease-resistant crops into agricultural practices in the 1940s helped to feed a growing human population. level: 1 true false

True

Most of the diversity of life on this planet is seen among the microbes True False

True

The bond between 2 amino acids is referred to as a peptide bond true false

True

The energy to carry out the movement of a ribosome comes from GTP True False

True

Amino acids can be spontaneously generated in vitro (in a laboratory), but only: under anaerobic conditions. at very low temperatures. under aerobic conditions. in an aqueous environment. at very high temperatures.

Under anaerobic conditions

In eukaryotes, which component is specific to the synthesis of only one type of protein? a ribosome a transfer RNA an aminoacyl tRNA synthetase a messenger RNA an elongation factor

a messenger RNA

Proteins that prevent inappropriate folding of newly synthesized proteins are called: polymerases. enzymes. chaperones. ribosomes. synthetases.

chaperones.

The bond that forms between amino acids: connects amino groups and carboxyl groups of adjacent amino acids. connects amino groups and R groups of adjacent amino acids. connects water molecules and carboxyl groups of adjacent amino acids. can form between any chemical groups of adjacent amino acids. connects hydrogen atoms of adjacent amino acids.

connects amino groups and carboxyl groups of adjacent amino acids.

The unfolding of a protein by heat or chemical treatment is referred to as: disaggregation. hydrolysis. denaturation. depolymerization. uncoupling.

denaturation.

Triacylglycerols are used in cells primarily for: information storage. energy storage. cell membrane biosynthesis. movement. biological catalysis.

energy storage.

All ß sheets are comprised of protein strands running antiparallel to each other. true false

false

Most proteins retain metabolic activity when denatured. true false

false

Which of the species-species interactions is most likely to be mutually beneficial? human and yeast honeybee and apple flower two plant species sharing the same resources leaf-cutter ant and tropical plant

honeybee and apple flower

Secondary structures are stabilized by which type of interaction? hydrogen bonding hydrophobic clustering disulfide linkages van der Waals forces ionic bonding

hydrogen bonding

A small nuclear RNA (SNRNA): inhibits translation. regulates transcription. is required for RNA processing. Is a part of the ribosome. carries individual amino acids for use in translation. destroys RNA transcripts.

is required for RNA processing.

A deoxyribose linked to a thymine is referred to as a: nucleotide. nucleoside. purine nucleoside. nucleotide or purine nucleotide. purine nucleotide.

nucleoside.

At some point in their life cycle, all cells have a ____whereas not all cells have a(n)_____. plasma membrane; RNA or DNA plasma membrane; nuclear membrane nucleus; nuclear membrane nucleus; plasma membrane nucleus; cytoplasm

plasma membrane; nuclear membrane

Imagine that a researcher was able to travel back in time, shortly after the appearance of the first RNAS on Earth. What would she most likely find? multiple polycistronic mRNAS, which could be translated to generate several proteins precursors of tRNAs bound to nucleotides, and not amino acids proteins with complex primary, secondary, and tertiary structures precursors of tRNAs bound only to specific amino acids, such as glycine functional ribosomes that behave similarly to those found today

precursors of tRNAs bound to nucleotides, and not amino acids

Translation is the process by which: ribosomes synthesize protein from information in an RNA molecule. information in DNA is used to synthesize an exact copy of that DNA. a section of DNA is used as information to generate an RNA molecule. ribosomes read information in a DNA molecule and use it to synthesize protein. an RNA molecule is used to repair damage to a rellted DNA molecule.

ribosomes synthesize protein from information in an RNA molecule.

The fully folded structure of a functional protein composed of a single polypeptide chain is referred to as: quaternary. secondary. tertiary. primary.

tertiary.

Consider a phylogenetic tree. The deepest node on a phylogenetic tree represents: an organism that is the common ancestor for organisms not included in the tree. the common ancestor of a subset of the organisms included in the tree. the common ancestor of all organisms included in the tree. an organism that is unrelated to all other organisms included in the tree. Nothing; the node serves only as the starting point of the tree.

the common ancestor of all organisms included in the tree.

Binding sites for tRNA are located in: both ribosomal subunits. the small ribosomal subunit. the large ribosomal subunit. neither ribosomal subunit.

the large ribosomal subunit.

A cooperative effect can occur in some types of multi-subunit proteins, leading to improved function of the subunits when bound to each other. true false

true

Which interaction helps stabilize the tertiary level of protein organization? a covalent bond between a positively charged R group and a negatively charged R group hydrogen bonding between the carbonyl oxygen of öne peptide bond and an amide hydrogen of a peptide bond hydrophilic clustering of non-polar R groups in the interior of a protein van der Waals interactions between R grobps in close proximity disulfide linkages between histidine residues

van der Waals interactions between R grobps in close proximity