1. What is the basic unit of heredity?
Answer:
Explanation:
A gene is the basic physical and functional unit of heredity. Genes, made up of DNA, act as instructions to make molecules called proteins. Each gene has the information required to build and maintain an organism's cells and pass genetic traits to offspring.
2. Which scientist(s) is/are credited with the discovery of the structure of DNA?
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Explanation:
James Watson and Francis Crick are credited with the discovery of the double helix structure of DNA in 1953. Their discovery was crucial in understanding how genetic information is stored and replicated.
3. What is the term for a variant form of a gene?
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Explanation:
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are diploid organisms where a typical body cell, or somatic cell, has two sets of chromosomes, one inherited from each parent.
4. Which process describes the creation of mRNA from a DNA template?
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Explanation:
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). This process is the first step in gene expression.
5. What is the term for an organism's observable characteristics?
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Explanation:
Phenotype refers to an organism's observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior. A phenotype results from the expression of an organism's genotype as well as the influence of environmental factors.
6. Which genetic disorder is characterized by the presence of an extra chromosome 21?
Answer:
Explanation:
Down Syndrome is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features, and mild to moderate intellectual disability.
7. In genetics, what is a genome?
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Explanation:
A genome is all the genetic material in an organism. It includes both the genes and the non-coding sequences of the DNA/RNA.
8. Which term describes the crossing over of chromosomes during meiosis?
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Explanation:
Recombination, or genetic recombination, is the process by which pieces of DNA are broken and recombined to produce new combinations of alleles. This process contributes to genetic diversity and occurs during meiosis through crossing over of chromosomes.
9. What is the principle of independent assortment?
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Explanation:
The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes. This means that the transmission of one gene will generally not affect the transmission of another.
10. What are the four nitrogenous bases in DNA?
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Explanation:
DNA contains four nitrogenous bases: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T). Adenine pairs with Thymine, and Guanine pairs with Cytosine, forming the rungs of the DNA double helix.
11. Which type of mutation involves the insertion or deletion of a base pair in the DNA sequence?
Answer:
Explanation:
A frame shift mutation occurs when a base pair is inserted or deleted from the DNA sequence, causing a shift in the way the sequence is read and translated into proteins. This can result in a completely altered protein product, as the entire sequence downstream of the mutation is affected.
12. What is the term for the phenomenon where one gene influences multiple phenotypic traits?
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Explanation:
Pleiotropy occurs when one gene influences multiple, seemingly unrelated phenotypic traits. This is a common feature in genetic disorders where a single gene defect can cause a cascade of effects in the organism.
13. Which genetic principle states that allele pairs separate independently during the formation of gametes?
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Explanation:
The Law of Segregation states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization. It explains how offspring can obtain a combination of alleles different from their parents.
14. What is a karyotype?
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Explanation:
A karyotype is a photograph or diagram of the chromosomes of an organism, typically displayed in pairs and ordered by size and shape. Karyotyping is used to identify and evaluate chromosomal abnormalities.
15. In genetics, what does homozygous mean?
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Explanation:
An individual is homozygous for a gene when they inherit identical alleles for that gene from both parents. This can result in either a dominant or recessive trait being expressed.
16. What is the function of tRNA in protein synthesis?
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Explanation:
Transfer RNA (tRNA) plays a crucial role in protein synthesis by carrying amino acids to the ribosome, where they are added to the growing polypeptide chain. Each tRNA molecule has an anticodon that pairs with a specific mRNA codon.
17. Which process describes the copying of DNA to DNA?
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Explanation:
DNA replication is the process of copying a DNA molecule to create two identical DNA molecules. This is an essential process prior to cell division, ensuring that each new cell receives an exact copy of the DNA.
18. What is a genome-wide association study (GWAS)?
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Explanation:
A genome-wide association study (GWAS) is an observational study of a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. GWASs are particularly useful in finding genetic variations that contribute to common, complex diseases.
19. In a diploid organism, a dominant allele will express itself if it is present:
Answer:
Explanation:
In diploid organisms, a dominant allele expresses itself even if it is present in just one copy (heterozygous condition) alongside a recessive allele. The dominant allele overshadows the recessive allele in determining the phenotype.
20. Which genetic disorder is caused by a defect in the hemoglobin gene leading to abnormal red blood cell shape?
Answer:
Explanation:
Sickle Cell Anemia is a genetic disorder caused by a mutation in the gene that tells the body to make hemoglobin, the protein that allows red blood cells to carry oxygen. This mutation results in red blood cells that are rigid and shaped like sickles or crescent moons.
21. What is the main cause of genetic diversity within a population?
Answer:
Explanation:
Mutation, the change in the DNA sequence, is the primary source of genetic diversity. These changes can introduce new genetic variants in a population, providing material for natural selection to act upon.
22. In human genetics, what is the male-determining sex chromosome?
Answer:
Explanation:
The Y chromosome is the male-determining sex chromosome in humans. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The presence of the Y chromosome leads to the development of male characteristics.
23. What is epigenetics?
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Explanation:
Epigenetics is the study of heritable changes in gene expression that do not involve alterations to the DNA sequence. These changes can affect how genes are turned on or off and are influenced by various factors, including environment and lifestyle.
24. What does the term 'polygenic' mean in genetics?
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Explanation:
Polygenic traits are those controlled by more than one gene. Each gene may have a small additive effect on the phenotype, and these traits often show a continuous distribution in a population, such as height or skin color.
25. What is a Barr body?
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Explanation:
A Barr body is the inactive X chromosome in a female somatic cell. Females have two X chromosomes and inactivation of one of them forms a Barr body, ensuring that females, like males, have one functional copy of the X chromosome.
26. Which of the following is a method used to study gene function?
Answer:
Explanation:
Gene knockout is a genetic technique where a gene of interest is made inoperative ("knocked out") in a model organism. This is done to study the effects of the loss of gene function and understand its role in the organism.
27. What is the function of restriction enzymes in genetic engineering?
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Explanation:
Restriction enzymes are used in genetic engineering to cut DNA at specific sequences. This allows scientists to manipulate and recombine DNA fragments in various ways, useful in cloning, gene splicing, and other genetic modifications.
28. What is a genotype?
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Explanation:
The genotype of an organism is its complete set of genetic material, including all of its genes. It is distinct from the phenotype, which is the organism's observable characteristics or traits.
29. What is the central dogma of molecular biology?
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Explanation:
The central dogma of molecular biology describes the flow of genetic information within a biological system. It states that genetic information flows from DNA to RNA to Protein, indicating the directional process of transcription and translation.
30. Which phenomenon describes the close association of two or more different species' genetic material?
Answer:
Explanation:
Horizontal gene transfer is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring. This process plays a significant role in the evolution of many organisms, allowing for the sharing of genes between different species.