1.
What protects the cell from water loss?
Correct Answer
A. Cuticle
Explanation
The cuticle is a waxy layer that covers the outer surface of the plant cell, acting as a waterproof barrier. This layer prevents excessive water loss from the cell through evaporation, helping to maintain the cell's hydration and prevent dehydration. Stomata, on the other hand, are small openings on the surface of the cell that allow for gas exchange but can also lead to water loss. The calvin cycle and chlorophyll A are not directly involved in protecting the cell from water loss.
2.
What does RFLP stand for?
Correct Answer
A. Restriction Fragment Length PolymorpHism.
Explanation
RFLP stands for Restriction Fragment Length Polymorphism. This technique is used in molecular biology to analyze differences in DNA sequences. It involves cutting DNA molecules into fragments using restriction enzymes and then separating them based on their size using gel electrophoresis. The resulting pattern of DNA fragments can be used to identify genetic variations or mutations.
3.
Crossing over occurs where?
Correct Answer
C. The centromere
Explanation
Crossing over occurs at the centromere during meiosis. This is the region where the sister chromatids are held together and where the microtubules of the spindle fiber attach during cell division. Crossing over is a process that involves the exchange of genetic material between homologous chromosomes, resulting in genetic variation. It occurs during prophase I of meiosis and is essential for the proper segregation of chromosomes during gamete formation.
4.
How do bacteria protect their own restriction site?
Correct Answer
B. By adding a methyl group.
Explanation
Bacteria protect their own restriction site by adding a methyl group. This modification prevents their own restriction enzymes from cutting the DNA at the restriction site. Methylation of the restriction site acts as a protective mechanism, allowing the bacteria to distinguish their own DNA from foreign DNA and avoid self-digestion. This enables the bacteria to maintain the integrity of their own genetic material while selectively degrading foreign DNA.
5.
What did we use to make the gel for the gel electrophoresis lab?
Correct Answer
C. Agarose
Explanation
Agarose is the correct answer because it is commonly used to make the gel for gel electrophoresis labs. Agarose is a polysaccharide derived from seaweed and it forms a gel-like substance when mixed with a buffer solution. This gel provides a medium through which DNA or proteins can be separated based on their size and charge during electrophoresis. Agarose gels have a low melting point and are easy to handle, making them ideal for this laboratory technique.
6.
What is the lowest wave length/color in the visible spectrum?
Correct Answer
C. 380nm/violet
Explanation
The lowest wavelength/color in the visible spectrum is violet, which has a wavelength of 380nm. In the visible spectrum, colors range from red, with the longest wavelength, to violet, with the shortest wavelength. Violet light has a higher frequency and energy compared to other colors in the visible spectrum.
7.
What is the longest phase of the cell cycle?
Correct Answer
D. InterpHase
Explanation
Interphase is the longest phase of the cell cycle. This is the period between cell divisions where the cell grows and carries out its normal functions. During interphase, the cell undergoes DNA replication, preparing for cell division. It consists of three stages: G1 (growth), S (synthesis - where DNA replication occurs), and G2 (growth and preparation for division). This phase is essential for the cell's growth and development before it enters the next phase, mitosis.
8.
Where is oxygen, the product, derived from in photosynthesis?
Correct Answer
B. H2O
Explanation
In photosynthesis, oxygen, the product, is derived from water (H2O). During the light-dependent reactions of photosynthesis, water molecules are split, and oxygen gas is released as a byproduct. This process occurs in the thylakoid membrane of the chloroplasts. The oxygen produced is then released into the atmosphere, providing a vital source of oxygen for living organisms.
9.
What is the charge of DNA?
Correct Answer
B. Negative
Explanation
DNA is a negatively charged molecule due to the presence of phosphate groups in its structure. These phosphate groups contain negatively charged ions, which contribute to the overall negative charge of DNA. This negative charge allows DNA to interact with positively charged molecules, such as histones, during the packaging of DNA into chromatin. Additionally, the negative charge of DNA also plays a role in its migration during processes like gel electrophoresis, where DNA fragments move towards the positive electrode.
10.
What nitrogenous bases are paired correctly for DNA?
Correct Answer
D. Cytosine+Guanine
Explanation
The correct answer is Cytosine+Guanine. In DNA, cytosine always pairs with guanine through hydrogen bonding. This pairing is known as complementary base pairing, where cytosine forms three hydrogen bonds with guanine. Adenine pairs with thymine in DNA, not uracil. Uracil is found in RNA instead of thymine. Adenine also forms two hydrogen bonds with thymine.