which of the following best explains how some cells of an individual produce and secrete a specific enzyme, but other cells of the same individual do not?
James
Guys, does anyone know the answer?
get which of the following best explains how some cells of an individual produce and secrete a specific enzyme, but other cells of the same individual do not? from EN Bilgi.
ap bio final Flashcards
Start studying ap bio final. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
ap bio final
308 studiers in the last day
which of the following best desrcibes the hydrolysis of carbohydrates?
Click card to see definition 👆
The addition of a water molecule breaks a covalent bond between sugar monomers.
Click again to see term 👆
which of the following best describes a charcteristic of DNA that makes it useful as hereditary material?
Click card to see definition 👆
Nucleotide bases in one strand can only be paired with specific bases in the other strand
Click again to see term 👆
1/59 Created by Esupat
Terms in this set (59)
which of the following best desrcibes the hydrolysis of carbohydrates?
The addition of a water molecule breaks a covalent bond between sugar monomers.
which of the following best describes a charcteristic of DNA that makes it useful as hereditary material?
Nucleotide bases in one strand can only be paired with specific bases in the other strand
Based on the pedigree in Figure 1, which of the following best explains the observed pattern of inheritance?
The trait is autosomal recessive, because the cross between individuals I-1 and I-2 produced an affected offspring
Which of the following best describes the process by which the bacteria are breaking down the glucose to produce lactic acid?
The bacteria are breaking down sugars in the absence of oxygen
Which of the following was the dependent variable in the researcher's experiment?
pH
Based on the data in Table 1, which of the following is the earliest time point at which there is a statistical difference between the control and treatment groups?
35 minutes
According to the data which of the following best explains the results of the experiment?
The pH of treatment culture was lower than the pH of the control because the chemical increased the bacterial metabolic rate
A mutation in the gene coding for a single-polypeptide enzyme results in the substitute of the amino acid serine, which has a polar R group, by the amino acid phenylalanine, which has a nonpolar R group. When researchers test the catalysis of the normal enzyme and the mutated enzyme, they find that the mutated enzyme has much lower activity than the normal enzyme does.
Which of the following most likely explains how the amino acid substitution has resulted in decreased catalytic activity by the mutated enzyme?
The substitute altered the secondary and tertiary structure of the enzyme so that the mutated enzyme folds into a different shape than the normal enzyme does
Pitcher plants are carnivorous plants that grow in areas where the soil contains low levels of key nutrients such as nitrogen. To obtain these nutrients, most pitchers plants capture prey using traps containing a digestive fluid. The captured prey are then broken down and digested, and the pitcher plant absorbs the nutrients.
The traps of one species of the pitcher plant, Nepenthes hemsleyana, do not contain digestive fluid. Instead they provide a suitable place for woolly bats (Kerivoula hardwickii) to sleep. The feces from the bat are released into the trap where nutrients in the feces are absorbed and provide the plants with the nitrogen it needs.
Which of the following best describes the relationship between the pitcher plants and the woolly bat?
The relationship is an example of mutualism because both the plant and the bat benefit
A particular genetic disorder is associated with a single gene with two recessive allele are affected. The prevalence of the disorder is 1 in 6,600.
Assuming the population is in Hardy-Weinberg equilibrium, which of the following is closest to the frequency of carriers in the Genet population?
.02430
Blood vessels are surrounded by cells called smooth muscle cells. Nitric oxide triggers a signaling cascade in smooth muscle cells that causes the cells to relax(figure 1).
Which of the following is represented by the gradual increase in thickness of the arrows from the top of the bottom of figure 1?
The number signaling molecules that are produced or activated increases with each step in the pathway.
Based on Table 1, which of the following best explains the difference in water potential between certain solutions and the grapes?
Grape soda and NaCI have a lower water potential because these two solutions caused the grape to lose water
Based on Table 1, which of the following percentages is closest to solute concentration of the grape?
5.5%
A student hypothesizes that the solute concentration of grape juice is higher than the solute concentration of the actual grape because the grape juice has added sugar.
Based on the data in Table 1, which of the following best evaluates the students hypothesis?
The hypothesis is not supported because the mass of the grape increased in the grape juice
Assuming a negligible pressure potential, which of the following best predicts the net movement of the small diffusible solutes and water in the second experiment (table 2)?
Small diffusible solutes will diffuse into the grape cells, followed by water
Mercurial sulfhydryl is an inhibitor of aquaporins which of the following is the most likely effect of adding mercurial sulfhydryl to distilled water solutions?
The grape cell will gain water more slowly because lack of facilitated diffusion.
Studying Gene Expression and Function
Ultimately, one wishes to determine how genes—and the proteins they encode—function in the intact organism. Although it may sound counterintuitive, one of the most direct ways to find out what a gene does is to see what happens to the organism when that gene is missing. Studying mutant organisms that have acquired changes or deletions in their nucleotide sequences is a time-honored practice in biology. Because mutations can interrupt cellular processes, mutants often hold the key to understanding gene function. In the classical approach to the important field of genetics, one begins by isolating mutants that have an interesting or unusual appearance: fruit flies with white eyes or curly wings, for example. Working backward from the phenotype—the appearance or behavior of the individual—one then determines the organism's genotype, the form of the gene responsible for that characteristic (Panel 8-1).
An official website of the United States government
Log in Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation Bookshelf
Browse Titles Advanced
Help
By agreement with the publisher, this book is accessible by the search feature, but cannot be browsed.
Molecular Biology of the Cell. 4th edition.
Show details
Studying Gene Expression and Function
Ultimately, one wishes to determine how genes—and the proteins they encode—function in the intact organism. Although it may sound counterintuitive, one of the most direct ways to find out what a gene does is to see what happens to the organism when that gene is missing. Studying mutant organisms that have acquired changes or deletions in their nucleotide sequences is a time-honored practice in biology. Because mutations can interrupt cellular processes, mutants often hold the key to understanding gene function. In the classical approach to the important field of genetics, one begins by isolating mutants that have an interesting or unusual appearance: fruit flies with white eyes or curly wings, for example. Working backward from the phenotype—the appearance or behavior of the individual—one then determines the organism's genotype, the form of the gene responsible for that characteristic (Panel 8-1).
Panel 8-1
Review of Classical Genetics.
Today, with numerous genome projects adding tens of thousands of nucleotide sequences to the public databases each day, the exploration of gene function often begins with a DNA sequence. Here the challenge is to translate sequence into function. One approach, discussed earlier in the chapter, is to search databases for well-characterized proteins that have similar amino acid sequences to the protein encoded by a new gene, and from there employ some of the methods described in the previous section to explore the gene's function further. But to tackle directly the problem of how a gene functions in a cell or organism, the most effective approach involves studying mutants that either lack the gene or express an altered version of it. Determining which cellular processes have been disrupted or compromised in such mutants will then frequently provide a window to a gene's biological role.
In this section, we describe several different approaches to determining a gene's function, whether one starts from a DNA sequence or from an organism with an interesting phenotype. We begin with the classical genetic approach to studying genes and gene function. These studies start with a for isolating mutants of interest, and then proceed toward identification of the gene or genes responsible for the observed phenotype. We then review the collection of techniques that fall under the umbrella of , in which one begins with a gene or gene sequence and attempts to determine its function. This approach often involves some intelligent guesswork—searching for homologous sequences and determining when and where a gene is expressed—as well as generating mutant organisms and characterizing their phenotype.
Go to:
The Classical Approach Begins with Random Mutagenesis
Before the advent of gene cloning technology, most genes were identified by the processes disrupted when the gene was mutated. This classical genetic approach—identifying the genes responsible for mutant phenotypes—is most easily performed in organisms that reproduce rapidly and are amenable to genetic manipulation, such as bacteria, yeasts, nematode worms, and fruit flies. Although spontaneous mutants can sometimes be found by examining extremely large populations—thousands or tens of thousands of individual organisms—the process of isolating mutants can be made much more efficient by generating mutations with agents that damage DNA. By treating organisms with mutagens, very large numbers of mutants can be created quickly and then screened for a particular defect of interest, as we will see shortly.
An alternative approach to chemical or radiation mutagenesis is called This method relies on the fact that exogenous DNA inserted randomly into the genome can produce mutations if the inserted fragment interrupts a gene or its regulatory sequences. The inserted DNA, whose sequence is known, then serves as a molecular tag that aids in the subsequent identification and cloning of the disrupted gene (Figure 8-55). In , the use of the transposable P element to inactivate genes has revolutionized the study of gene function in the fruit fly. Transposable elements (see Table 5-3, p. 287) have also been used to generate mutants in bacteria, yeast, and in the flowering plant . Retroviruses, which copy themselves into the host genome (see Figure 5-73), have been used to disrupt genes in zebrafish and in mice.
Figure 8-55
Insertional mutant of the snapdragon, A mutation in a single gene coding for a regulatory protein causes leafy shoots to develop in place of flowers. The mutation allows cells to adopt a character that would be appropriate to a different (more...)
Such studies are well suited for dissecting biological processes in worms and flies, but how can we study gene function in humans? Unlike the organisms we have been discussing, humans do not reproduce rapidly, and they are not intentionally treated with mutagens. Moreover, any human with a serious defect in an essential process, such as DNA replication, would die long before birth.
Guys, does anyone know the answer?