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 several differences. One major difference is that DNA is responsible for maintaining genetic information, while RNA helps in constructing proteins based on that genetic information. DNA acts as a blueprint and stores the genetic instructions, while RNA plays a role in protein synthesis by carrying the genetic code from DNA to the ribosomes, where proteins are made. 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
B. Both need to obtain energy.
Explanation
Autotrophs and heterotrophs are similar in the sense that both need to obtain energy. Autotrophs are able to produce their own energy through photosynthesis, while heterotrophs obtain energy by consuming other organisms. Despite the different methods of energy acquisition, both autotrophs and heterotrophs require energy to carry out their metabolic processes and sustain life.
3.
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.
4.
What is the process that copies a gene’s DNA sequence into a sequence of RNA?
Correct Answer
A. Transcription
Explanation
Transcription is the process that copies a gene's DNA sequence into a sequence of RNA. During transcription, an enzyme called RNA polymerase binds to the DNA and synthesizes a complementary RNA molecule using the DNA template. This RNA molecule, known as messenger RNA (mRNA), carries the genetic information from the DNA to the ribosomes where it is translated into a protein during the process of translation. Therefore, transcription is the correct answer as it accurately describes the process of copying a gene's DNA sequence into RNA.
5.
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 in the form of ATP through cellular respiration. Without mitochondria, the cell will not be able to generate enough energy to carry out its metabolic processes. Respiration is essential for the cell to survive and perform its functions, so the absence of mitochondria will result in the inability to carry out respiration.
6.
Which process produces the most variation within a species?
Correct Answer
D. Sexual reproduction
Explanation
Sexual reproduction produces the most variation within a species. This is because during sexual reproduction, genetic material from two parents combines to create offspring with a unique combination of traits. This genetic recombination through processes such as crossing over and independent assortment leads to a greater diversity of traits within a population. In contrast, mitosis produces genetically identical cells, cloning produces genetically identical organisms, and asexual reproduction involves the production of offspring without the involvement of genetic recombination.
7.
Why is meiosis important for sexual reproduction?
Correct Answer
C. It allows gametes to have half the original number of chromosomes of the organism.
Explanation
Meiosis is important for sexual reproduction because it allows gametes (sperm and egg cells) to have half the original number of chromosomes of the organism. This is necessary to ensure that when the gametes fuse during fertilization, the resulting zygote has the correct number of chromosomes. If gametes had the same number of chromosomes as the organism, the zygote would have double the number of chromosomes, which would result in genetic abnormalities and developmental issues. Meiosis ensures the proper reduction of chromosome number, allowing for genetic diversity and the formation of healthy offspring.
8.
How would overexposure to X-rays affect most animal cells?
Correct Answer
B. 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 high-energy radiation that can break the chemical bonds in DNA, leading to changes in the sequence of DNA nucleotides. This can result in mutations, which can have various effects on the affected cells. Therefore, the correct answer is that overexposure to X-rays would change the sequence of DNA nucleotides in affected cells.
9.
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 organisms that have been genetically modified by inserting genes from another species. By doing so, scientists can create organisms that produce specific proteins or substances that can be used to treat diseases. This method allows for the production of therapeutic proteins, vaccines, and other medical treatments that can help in combating various diseases and improving human health.
10.
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. ATP and NADPH are produced during the light-dependent reactions of photosynthesis, which occur in the photosystems. These energy-rich molecules are then used in the Calvin cycle, which is the light-independent reactions of photosynthesis. In the Calvin cycle, ATP and NADPH provide the energy and reducing power needed to convert carbon dioxide into glucose and other sugars. Therefore, the photosystems play a crucial role in transferring energy to the Calvin cycle through ATP and NADPH.
11.
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 initial step in cellular respiration where glucose is broken down into pyruvate molecules. It occurs in the cytoplasm of the cell and does not require oxygen. Glycolysis is a universal metabolic pathway and is the first step in both aerobic and anaerobic respiration.
12.
The major source of the oxygen that is released into the atmosphere is
Correct Answer
B. pHotosynthesis
Explanation
Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose and oxygen. During photosynthesis, plants use energy from the sun to produce glucose, which is used as a source of energy, and release oxygen as a byproduct. This oxygen is then released into the atmosphere, making photosynthesis the major source of oxygen in the atmosphere. Cellular respiration, on the other hand, is the process by which organisms break down glucose to release energy, and while it does release some oxygen, it is not the major source of oxygen in the atmosphere. Automobile exhaust and the weathering of rocks do not release significant amounts of oxygen into the atmosphere.
13.
Which statement best describes the primary function of DNA replication?
Correct Answer
A. To ensure daughter cells have a complete copy of the DNA
Explanation
The primary function of DNA replication is to ensure that daughter cells receive an exact and complete copy of the DNA. This is essential for the accurate transmission of genetic information from one generation to the next. By duplicating the DNA, each daughter cell can inherit the same genetic material as the parent cell, allowing for the proper functioning and development of the organism.
14.
Which cellular process converts solar energy into chemical energy?
Correct Answer
D. pHotosynthesis
Explanation
Photosynthesis is the correct answer because it is the cellular process by which plants, algae, and some bacteria convert solar energy into chemical energy. During photosynthesis, these organisms use sunlight, water, and carbon dioxide to produce glucose (a type of sugar) and oxygen. This process occurs in the chloroplasts of plant cells, specifically in the chlorophyll-containing structures called thylakoids. The energy stored in glucose molecules is then used by the organism for various metabolic processes, such as growth and reproduction.
15.
An ion must cross the cell membrane through active transport instead of passive transport when the ion is ___.
Correct Answer
C. Going against the concentration gradient
Explanation
Active transport is a process that requires energy to move substances across the cell membrane, against their concentration gradient. In this case, the ion is going against the concentration gradient, meaning it is moving from an area of lower concentration to an area of higher concentration. This requires energy in the form of ATP and cannot occur through passive transport, which relies on the concentration gradient for movement. Therefore, the ion must cross the cell membrane through active transport.