1.
Which describes a difference between DNA and RNA?
Correct Answer
D. DNA maintains genetic information whereas RNA helps construct proteins based on genetic information.
Explanation
DNA and RNA have different roles in the cell. DNA is responsible for maintaining the genetic information, which is passed on from one generation to another. It serves as a template for RNA synthesis. On the other hand, RNA plays a crucial role in protein synthesis. It helps in constructing proteins based on the genetic information encoded in DNA. Therefore, the correct answer is that DNA maintains genetic information whereas RNA helps construct proteins based on genetic information.
2.
Which is similar between autotrophs and heterotrophs?
Correct Answer
A. Both need to obtain energy.
Explanation
Autotrophs and heterotrophs are both organisms that require energy to survive. Autotrophs, such as plants, are able to produce their own energy through photosynthesis, while heterotrophs, such as animals, obtain energy by consuming other organisms. In both cases, the organisms need to obtain energy in order to carry out their metabolic processes and maintain their life functions. Therefore, the similarity between autotrophs and heterotrophs lies in their shared need to obtain energy.
3.
Which must be true of any hypothesis?
Correct Answer
A. Must be testable
Explanation
For a hypothesis to be considered valid, it must be testable. This means that it should be possible to design experiments or gather evidence that can either support or refute the hypothesis. Without testability, a hypothesis cannot be scientifically investigated or validated. Therefore, this statement is true and essential for any hypothesis.
4.
What will most likely be the result if all of the mitochondria are removed from a plant cell?
Correct Answer
A. It will be unable to carry out respiration.
Explanation
If all of the mitochondria are removed from a plant cell, it will be unable to carry out respiration. Mitochondria are responsible for producing energy through cellular respiration, which is essential for the cell to function properly. Without mitochondria, the cell will not be able to generate ATP, the energy currency of the cell, and therefore will not be able to carry out essential metabolic processes.
5.
What is the process that copies a gene’s DNA sequence into a sequence of RNA?
Correct Answer
C. Transcription
Explanation
Transcription is the process that copies a gene's DNA sequence into a sequence of RNA. During transcription, RNA polymerase binds to the DNA template strand and synthesizes a complementary RNA molecule using base pairing rules. This process is essential for gene expression as it produces messenger RNA (mRNA) molecules that can be translated into proteins during the process of translation.
6.
Which statement best compares aerobic and anaerobic respiration?
Correct Answer
A. Less ATP is generated during anaerobic respiration than during aerobic respiration.
Explanation
During aerobic respiration, which occurs in the presence of oxygen, more ATP is generated compared to anaerobic respiration, which occurs in the absence of oxygen. This is because aerobic respiration involves the complete breakdown of glucose, producing more energy in the form of ATP. In contrast, anaerobic respiration involves the incomplete breakdown of glucose, resulting in the production of less ATP. Therefore, the statement "Less ATP is generated during anaerobic respiration than during aerobic respiration" is the best comparison between the two processes.
7.
Which describes when two different species utilize the same resource?
Correct Answer
D. Competition
Explanation
Competition describes the scenario when two different species utilize the same resource. In this situation, both species are in direct competition with each other for limited resources such as food, water, or shelter. This competition can lead to a decrease in the availability of resources for both species, potentially affecting their survival and population sizes.
8.
A human male gamete cell contains ___ chromosomes and is said to be ___ which is symbolized by ___.
Correct Answer
B. 23 … haploid … 1n
Explanation
A human male gamete cell contains 23 chromosomes and is said to be haploid, which is symbolized by 1n.
9.
Which process produces the most variation within a species?
Correct Answer
D. Sexual reproduction
Explanation
Sexual reproduction produces the most variation within a species because it involves the combination of genetic material from two different individuals, resulting in offspring with a unique combination of traits. This genetic diversity allows for adaptation to changing environments and increases the chances of survival for a species. Asexual reproduction, mitosis, and cloning do not involve the exchange of genetic material and therefore do not generate as much variation within a species.
10.
Why is meiosis important for sexual reproduction?
Correct Answer
D. It allows the zygote formed from fertilization to have half the original number of chromosomes of the organism.
Explanation
Meiosis is important for sexual reproduction because it allows the zygote formed from fertilization to have half the original number of chromosomes of the organism. This is essential for maintaining the correct chromosome number in each generation and preventing an excessive accumulation of chromosomes. Meiosis ensures genetic diversity by shuffling and recombining genetic material during the formation of gametes. It also allows for the exchange of genetic material between homologous chromosomes through crossing over, further increasing genetic diversity.
11.
How would overexposure to X-rays affect most animal cells?
Correct Answer
C. It would change the sequence of DNA nucleotides in affected cells.
Explanation
Overexposure to X-rays can cause damage to DNA in cells. X-rays have high energy and can ionize atoms, leading to the formation of free radicals that can damage DNA molecules. This damage can result in changes to the sequence of DNA nucleotides in affected cells, which can have various consequences such as mutations or disruptions in gene expression. This can ultimately lead to cellular dysfunction or even cell death.
12.
Which is one reason scientists produce transgenic organisms?
Correct Answer
D. To treat certain types of diseases
Explanation
Scientists produce transgenic organisms to treat certain types of diseases. Transgenic organisms are genetically modified organisms that have been altered by introducing genes from another species. By introducing specific genes into these organisms, scientists can create new treatments and therapies for diseases. This can include producing transgenic animals that can produce human proteins or antibodies, which can then be used for medical purposes. By using transgenic organisms, scientists can develop new and more effective treatments for various diseases and medical conditions.
13.
What is the relationship between the photosystems and the Calvin cycle?
Correct Answer
C. The pHotosystems transfer energy to the Calvin cycle through ATP and NADpH.
Explanation
The photosystems transfer energy to the Calvin cycle through ATP and NADPH. This is because during photosynthesis, the photosystems in the thylakoid membrane of the chloroplasts absorb light energy and convert it into chemical energy in the form of ATP and NADPH. This energy is then used in the Calvin cycle, which takes place in the stroma of the chloroplasts, to convert carbon dioxide into glucose and other organic molecules. Therefore, the photosystems play a crucial role in providing the energy needed for the Calvin cycle to occur.
14.
The part of cellular respiration in which glucose is broken down is called___.
Correct Answer
B. Glycolysis
Explanation
Glycolysis is the correct answer because it is the part of cellular respiration where glucose is broken down. It is the first step in cellular respiration and occurs in the cytoplasm of the cell. During glycolysis, glucose is converted into two molecules of pyruvate, releasing a small amount of energy in the form of ATP and NADH. This process does not require oxygen and is the same in both aerobic and anaerobic respiration.
15.
In the diagram, structure A is the ___ and structure B is the ___.
Correct Answer
B. Inner membrane; matrix
Explanation
In this diagram, structure A is identified as the inner membrane, while structure B is identified as the matrix. The inner membrane is typically found in organelles such as mitochondria, where it separates the matrix from the intermembrane space. The matrix, on the other hand, refers to the innermost compartment of an organelle, such as the mitochondria or chloroplast, where various metabolic reactions occur. Therefore, in this diagram, structure A represents the inner membrane, and structure B represents the matrix.