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 functions in the cell. DNA is responsible for maintaining and storing genetic information, while RNA is involved in the process of protein synthesis. RNA helps to construct 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 need to obtain energy in order to survive. Autotrophs are able to produce their own energy through photosynthesis, while heterotrophs obtain energy by consuming other organisms. Despite the difference in how they obtain energy, the fact remains that both autotrophs and heterotrophs require energy to carry out their life processes. Therefore, the similarity between autotrophs and heterotrophs lies in the fact that they both need to obtain energy.
3.
Which must be true of any hypothesis?
Correct Answer
A. Must be testable
Explanation
Any hypothesis must be testable in order to be considered valid. This means that it must be possible to design experiments or gather evidence that can either support or refute the hypothesis. Without the ability to test a hypothesis, it cannot be scientifically evaluated or proven. Therefore, the statement "must be testable" is a necessary condition for any hypothesis to be considered valid.
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 the powerhouse of the cell and are responsible for producing energy in the form of ATP through cellular respiration. Without mitochondria, the cell will not be able to generate the energy needed for various cellular processes, including respiration.
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 and separates the two strands. It then uses one strand of the DNA as a template to synthesize a complementary RNA molecule. This process is essential for gene expression as it produces messenger RNA (mRNA) molecules that carry the genetic information from the DNA to the ribosomes for translation into proteins.
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 utilizes the complete breakdown of glucose, producing more energy in the form of ATP. In contrast, anaerobic respiration only partially breaks down 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 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 territory. This can lead to a decrease in the availability of resources for both species and can result in one species outcompeting the other for survival and reproduction.
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 parents. This results in offspring that have a unique combination of genes, leading to increased genetic diversity within the species. In contrast, asexual reproduction, mitosis, and cloning do not involve the recombination of genetic material and therefore do not generate as much variation within the 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 the process by which gametes (sperm and eggs) are formed. During meiosis, the number of chromosomes is halved, resulting in gametes that have half the original number of chromosomes of the organism. This is important for sexual reproduction because when the gametes fuse during fertilization, the resulting zygote will have the correct number of chromosomes for the species. If meiosis did not occur and the gametes had the same number of chromosomes as the organism, the zygote would have double the number of chromosomes, which could lead to genetic abnormalities and developmental issues.
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 molecules in cells. X-rays are a form of ionizing radiation, which means they have enough energy to remove tightly bound electrons from atoms, creating charged particles called ions. These ions can interact with DNA molecules, causing breaks in the DNA strands or changes in the sequence of DNA nucleotides. This can lead to mutations in the affected cells, which can have various negative effects, including potential disruptions in cell function and increased risk of cancer development. Therefore, the correct answer is that overexposure to X-rays would change the sequence of DNA nucleotides in affected cells.
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 created by introducing genes from one species into the genome of another, resulting in organisms with new traits or capabilities. In the context of disease treatment, scientists can use transgenic organisms to produce therapeutic proteins or develop new treatments. For example, transgenic bacteria can be engineered to produce insulin, which is used to treat diabetes. Therefore, producing transgenic organisms is a method employed by scientists to address specific diseases and improve medical treatments.
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 capture light energy and use it to generate ATP and NADPH. These energy-rich molecules are then used by the Calvin cycle to convert carbon dioxide into sugars. 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 process in cellular respiration where glucose is broken down into pyruvate. It takes place in the cytoplasm and does not require oxygen. Glycolysis is the first step 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 the given diagram, structure A is identified as the inner membrane and structure B is identified as the matrix. This suggests that structure A is a membrane that is located inside another structure, while structure B is a central space or compartment within that structure.