DNA structure
What is the shape of a DNA molecule?
The shape of a DNA molecule is a double helix, which resembles a twisted ladder.
What does a Punnett square illustrate?
A Punnett square illustrates all possible genetic combinations from a cross between two parents.
What is a frameshift mutation?
A frameshift mutation occurs when nucleotides are inserted or deleted from the DNA sequence, altering the reading frame of the genetic code.
What are the two main stages of meiosis?
The two main stages of meiosis are meiosis I and meiosis II.
What is the purpose of using restriction enzymes in genetic engineering?
Restriction enzymes are used to cut DNA at specific sequences, allowing for the insertion or modification of genes in genetic engineering.
What is the role of hydrogen bonds in DNA?
Hydrogen bonds between complementary nitrogenous bases hold the two strands of the DNA double helix together.
If a heterozygous (Bb) individual is crossed with a homozygous recessive (bb) individual, what is the expected genotype ratio of the offspring?
The expected genotype ratio of the offspring will be 1 Bb : 1 bb.
How can mutations be beneficial?
Beneficial mutations can provide an advantage to an organism, such as increased resistance to diseases or improved adaptation to environmental changes.
During which phase of meiosis does crossing over occur?
Crossing over occurs during prophase I of meiosis, allowing for genetic recombination between homologous chromosomes.
What is a transgenic organism?
A transgenic organism is one that has been genetically modified to contain DNA from another species, often for the purpose of enhancing certain traits.
How many chromosomes do humans have, and how are they organized?
Humans have 46 chromosomes, organized into 23 pairs, with one set inherited from each parent.
What is the phenotype ratio for a monohybrid cross between two heterozygous individuals (Tt x Tt)?
The phenotype ratio for this cross is 3 tall : 1 short, assuming tall (T) is dominant over short (t).
What is a silent mutation?
A silent mutation is a change in the DNA sequence that does not alter the amino acid produced, often due to the redundancy of the genetic code.
What is the significance of genetic diversity in meiosis?
Genetic diversity is significant because it increases the variability of traits in a population, which can enhance survival and adaptation in changing environments.
How can genetic engineering be used in medicine?
Genetic engineering can be used in medicine to produce insulin, gene therapy, and create vaccines through the modification of bacteria or other organisms.
What is the function of DNA?
The function of DNA is to store and transmit genetic information that guides the development, functioning, and reproduction of organisms.
What does the term "homozygous" mean?
Homozygous refers to having two identical alleles for a particular gene, either both dominant (AA) or both recessive (aa).
Mutations
What is the difference between spontaneous and induced mutations?
Spontaneous mutations occur naturally due to errors in DNA replication or repair, while induced mutations result from external factors such as chemicals or radiation.
What is independent assortment in meiosis?
Independent assortment refers to the random distribution of maternal and paternal chromosomes into gametes during metaphase I of meiosis, contributing to genetic variation.
What ethical concerns are associated with genetic engineering?
Ethical concerns include potential risks to health and the environment, the implications of designer babies, and the impact on biodiversity.
What is the difference between DNA and RNA?
The main differences between DNA and RNA are that DNA contains deoxyribose sugar, is double-stranded, and uses thymine (T) as a base, while RNA contains ribose sugar, is single-stranded, and uses uracil (U) instead of thymine.
What is the phenotype ratio for a monohybrid cross between two heterozygous individuals (Tt x Tt)?
The phenotype ratio for this cross is 3 tall : 1 short, assuming tall (T) is dominant over short (t).
Can mutations be passed on to the next generation?
Yes, mutations can be passed on to the next generation if they occur in germ cells (sperm or egg cells).
How many cells are produced at the end of meiosis, and what is their chromosome number?
At the end of meiosis, four genetically unique gametes are produced, each with half the chromosome number of the original cell (haploid).
What is CRISPR, and how is it used in genetic engineering?
CRISPR is a revolutionary gene-editing technology that allows for precise modifications to DNA, enabling scientists to edit genes quickly and accurately.