393 Questions
What is the primary function of DNA?
To store and transmit genetic information
Who proposed the double helix model of DNA in 1953?
James Watson
What is the structure of DNA often compared to?
A twisted ladder
Where does DNA replication occur in eukaryotic cells?
Nucleus
What is the critical timing for DNA replication within the cell cycle?
S phase
Where is DNA primarily located in eukaryotic cells?
Nucleus
Which cellular organelles, in addition to the nucleus, contain DNA?
Mitochondria and chloroplasts
What is the function of mitochondrial DNA (mtDNA) in cells?
Produces energy for the cell
Which structures are made of DNA and proteins called histones?
Chromosomes
What is the essential role of chloroplast DNA in plants?
Enables photosynthesis
Where is messenger RNA (mRNA) formed?
Nucleus
What is the primary function of transfer RNA (tRNA) in protein synthesis?
Transporting amino acids to the ribosome
Which nitrogenous base is unique to RNA and replaces thymine found in DNA?
Uracil (U)
Where is ribosomal RNA (rRNA) located within the cell?
Ribosomes
What is the main role of messenger RNA (mRNA) in protein synthesis?
Carrying genetic code for protein synthesis
During transcription, what happens after DNA unwinding?
Template strand acts as a template for mRNA synthesis
Where does meiosis occur in animals?
Sex organs during gametogenesis
What is the role of tRNA during translation?
Carry specific amino acids and have anticodons
During meiosis I, what happens in telophase I?
Nuclear membranes reform around each set of chromosomes
What is the main function of meiosis in terms of chromosome number?
Reduces the chromosome number by half
What is the role of helicases in DNA replication?
Facilitate unwinding of the DNA double helix
Which enzyme synthesizes a short RNA primer during DNA replication?
Primase
What is the significance of DNA replication in terms of genetic variation?
It contributes to genetic diversity within populations
Why is interpreting DNA profiles a cautious process?
Human errors, differences in lab methods, and potential non-unique DNA regions
What is the function of DNA polymerases during DNA replication?
Add nucleotides to the growing DNA strand
Which process results in the formation of genetically identical daughter cells?
Mitosis
What key event does not occur during mitosis but is crucial for genetic diversity in meiosis?
Crossing over
In which phase do homologous chromosomes pair up in meiosis I but not in mitosis?
Prophase
Which concept involves different forms of a gene occurring at the same locus on homologous chromosomes?
Alleles
What concept refers to a genetic situation where the dominant allele completely masks the expression of the recessive allele in the heterozygous condition?
Complete dominance
During Prophase II of meiosis, what happens to the chromosomes?
Chiasmata formation occurs.
What is the significance of meiosis in maintaining chromosome number?
It reduces chromosome number from diploid to haploid.
Which process during meiosis contributes most to genetic variation within a species?
Crossing over in Prophase I
What is non-disjunction in meiosis and what possible outcome can it lead to?
It results in gametes with an abnormal number of chromosomes, potentially causing genetic conditions like Down Syndrome.
What is a key difference between mitosis and meiosis in terms of the number of daughter cells produced?
Mitosis produces two daughter cells, while meiosis results in four daughter cells.
What is the main difference between incomplete dominance and complete dominance?
Incomplete dominance involves alleles being equally expressed, while complete dominance masks one allele over the other.
In co-dominance, what happens to the expression of alleles?
Both alleles are fully expressed without blending.
Which genetic concept involves having more than two alternative forms of a gene at the same locus?
Multiple Alleles
What is the main focus of monohybrid crosses in genetics?
Inheritance of single traits
What is the cornerstone principle in genetics that explains how traits are transmitted from parents to offspring?
Mendel's Principle of Segregation
Where is DNA primarily located in eukaryotic cells?
Nucleus
What is the function of mitochondrial DNA (mtDNA) in cells?
Producing energy
Which organelle is responsible for converting light energy into chemical energy in plants?
Chloroplast
What is the main role of messenger RNA (mRNA) in protein synthesis?
Providing instructions for protein assembly
What is the unique nitrogenous base found in RNA that replaces thymine in DNA?
Uracil
What is the primary function of DNA?
Transmitting genetic information
Which phase of the cell cycle does DNA replication occur?
Interphase
What holds the two strands of DNA together in the double helix structure?
Hydrogen bonds
What is the role of regulatory regions in DNA?
Controlling gene expression
During which cell phase does DNA replication take place in eukaryotic cells?
S phase
Where is messenger RNA (mRNA) formed?
Nucleus
What is the primary function of transfer RNA (tRNA) in protein synthesis?
Facilitating transportation of amino acids to the ribosome
Which nitrogenous base is unique to RNA and replaces thymine found in DNA?
Uracil (U)
What is the location of ribosomal RNA (rRNA) within the cell?
Ribosomes
What structure forms the backbone of the RNA molecule?
Sugar-phosphate backbone
What is the role of primase during DNA replication?
Synthesizing a long RNA strand
Why is the termination step important in DNA replication?
To join Okazaki fragments on the lagging strand
What is the main significance of DNA replication for genetic diversity?
Leading to mutations that cause genetic diversity
In DNA fingerprinting, what does a match between bands in evidence and reference samples suggest?
The samples are from the same source
What is the main function of ligase enzymes in DNA replication?
Joining Okazaki fragments on the lagging strand
What role does the template strand play during transcription in protein synthesis?
It serves as a template for mRNA synthesis.
In which stage of protein synthesis does the ribosome reach a stop codon on the mRNA?
Translation
Where does meiosis occur in plants for the production of spores and gametophytes?
Anthers and ovules
What is the function of tRNA molecules during translation in protein synthesis?
Carrying specific amino acids
During meiosis I, what is the significance of homologous chromosomes aligning at the cell equator?
Ensures genetic variation
What is the main difference between mitosis and meiosis in terms of chromosome number?
Mitosis maintains the diploid chromosome number, while meiosis reduces it to haploid.
During which stage of meiosis does genetic material exchange between homologous chromosomes occur?
Prophase I
What is the significance of non-disjunction during meiosis?
It can result in gametes with an abnormal number of chromosomes.
Which stage of meiosis involves the separation of sister chromatids toward opposite poles?
Anaphase I
What is the primary benefit of crossing over during meiosis?
To allow for genetic diversity by exchanging genetic material.
What is the key difference between complete dominance and incomplete dominance?
In complete dominance, one allele masks the presence of another, while in incomplete dominance, neither allele is completely dominant.
What is the defining characteristic of co-dominance?
Both alleles are equally expressed without blending.
What is the role of Mendel's Principle of Segregation in genetics?
Separating alleles during gamete formation to ensure each gamete carries only one allele for each trait.
How do monohybrid crosses contribute to genetics?
By focusing on the inheritance of single traits and predicting offspring genotypes and phenotypes.
What ensures genetic diversity in offspring according to Mendel's Principle of Segregation?
The formation of gametes with only one allele for each trait.
What is the main difference between mitosis and meiosis in terms of genetic diversity?
Mitosis results in genetically identical daughter cells while meiosis leads to genetically different daughter cells.
What is the significance of crossing over in meiosis?
It increases genetic variability among produced gametes.
Which concept refers to having two different forms of a gene at the same locus on homologous chromosomes?
Alleles
In genetics, what does the Law of Dominance state?
Individuals heterozygous for a characteristic exhibit the dominant trait in their phenotype.
What is the primary function of chromosomes during cell division?
To carry genetic information and ensure proper distribution to daughter cells
Where is DNA primarily located in eukaryotic cells?
Nucleus
What is the role of helicases in DNA replication?
Unwinding the DNA double helix
What is the role of mitochondrial DNA (mtDNA) in cells?
Producing energy
Why is interpreting DNA profiles approached cautiously?
Due to differences in DNA replication between laboratories
Which organelle besides the nucleus contains DNA in eukaryotic cells?
Mitochondria
What is the significance of ligase enzymes in DNA replication?
Joining Okazaki fragments on the lagging strand
What is the function of chloroplast DNA in plants?
Enabling photosynthesis
What is the primary function of primase in DNA replication?
Synthesizing RNA primers
What are chromosomes made of in eukaryotic cells?
Histones and DNA
Why is proofreading by DNA polymerases important during DNA replication?
To ensure fidelity and minimize errors in base pairing
During DNA replication, where does the process primarily take place in eukaryotic cells?
Nucleus
What is the main function of DNA polymerases during DNA replication?
Adding new nucleotides to the growing DNA strand
Which nitrogenous base pairs with adenine in DNA?
Thymine
What is the significance of DNA replication occurring during the S phase of the cell cycle?
It ensures each new cell receives a complete set of chromosomes.
Where is ribosomal RNA (rRNA) located within the cell?
Cytoplasm
What is the main function of messenger RNA (mRNA) in protein synthesis?
Carries the genetic code from DNA to the cytoplasm
What is the main role of transfer RNA (tRNA) during protein synthesis?
Transports amino acids to the ribosome
What is the location of messenger RNA (mRNA) formation?
Nucleus
What is the primary function of ribosomal RNA (rRNA) in protein synthesis?
Facilitates the assembly of amino acids into proteins
What is the main purpose of transcription in protein synthesis?
Production of functional proteins
What happens during the termination stage of translation in protein synthesis?
mRNA detaches from the DNA
During meiosis I, what is the significance of crossing over between chromatids?
Increases genetic diversity
Which stage of meiosis involves the reduction of the chromosome number by half?
Anaphase I
What is the primary function of transfer RNA (tRNA) in translation during protein synthesis?
Transports amino acids
Which process is responsible for the formation of four genetically different daughter cells?
Meiosis
What is the primary role of chromatin in the cell?
Forming chromosomes during cell division
In genetics, what do recessive alleles exhibit when in the heterozygous condition?
They are masked
Which concept involves the genetic makeup of an organism, determining its specific characteristics?
Genotype
What is the role of non-disjunction during meiosis?
Results in an abnormal number of chromosomes in gametes
During which phase of meiosis do homologous chromosome pairs line up on the equator?
Metaphase
Which phase of meiosis involves the division of centromeres and pulling sister chromatids toward opposite poles?
Anaphase II
What is the main difference between genetic variation introduced by crossing over and random assortment during meiosis?
Crossing over involves homologous chromosome exchange, while random assortment involves alignment at the equator
What genetic condition results from non-disjunction of chromosome pair 21?
Down Syndrome
At which phase of meiosis do sister chromatids separate, resulting in individual chromosomes moving to opposite poles?
Anaphase II
What is the main difference between incomplete dominance and complete dominance?
Incomplete dominance involves the blending of traits, while complete dominance only shows one trait.
How does co-dominance differ from incomplete dominance?
Co-dominance involves both alleles being equally expressed, while incomplete dominance results in an intermediate phenotype.
Why is understanding monohybrid crosses essential in genetics?
To track the inheritance of alleles for a single gene from parents to offspring.
What happens during the formation of gametes according to Mendel's Principle of Segregation?
Alleles segregate and each gamete carries only one allele for each trait.
In a typical genetics cross format using Punnett squares, what do letters represent?
Alleles
What is the primary function of DNA?
To store and transmit genetic information in living organisms
What holds the two strands of DNA together in a double helix structure?
Hydrogen bonds between phosphate groups
What is the initial step in the process of DNA replication?
Initiation
During which phase of the cell cycle does DNA replication take place in eukaryotic cells?
S phase
What is the sequence of events involved in protein synthesis according to the central dogma of molecular biology?
Transcribing DNA into mRNA and then translating mRNA into proteins
Which enzyme is responsible for synthesizing a short RNA primer during DNA replication?
Primase
In DNA profiling, what do variations in the pattern of lines (bands) between two samples indicate?
Distinct DNA profiles
Where does DNA replication take place within a eukaryotic cell?
Nucleus
What is the significance of proofreading by DNA polymerases during replication?
Ensuring fidelity of replication
Why is understanding DNA replication crucial for fields like genetics and molecular biology?
To develop genetic therapies
What is the primary location of DNA in eukaryotic cells?
Nucleus
Which organelle, in addition to the nucleus, contains DNA in eukaryotic cells?
Mitochondria
What is the main function of mitochondrial DNA (mtDNA) in cells?
Energy production
Where is chloroplast DNA primarily essential for function in plants?
Photosynthesis
What is the role of histones in relation to DNA in eukaryotic cells?
Chromosome organization
Where is transfer RNA (tRNA) found within the cell?
Freely in the cytoplasm
What is the primary function of messenger RNA (mRNA) in protein synthesis?
Interpreting genetic code
Which of the following nitrogenous bases is unique to RNA and replaces thymine found in DNA?
Uracil (U)
What is the location of ribosomal RNA (rRNA) within the cell?
Within ribosomes
Which component makes up the structural framework of an RNA molecule?
Ribose sugar
During which phase of meiosis do homologous chromosomes exchange genetic material at points called chiasmata?
Prophase I
What is the consequence of non-disjunction during Anaphase I or II in meiosis?
Gametes with an abnormal number of chromosomes
Which stage of meiosis involves the division of centromeres and the separation of sister chromatids?
Anaphase II
What is the primary role of meiosis in maintaining a constant chromosome number from one generation to the next?
Halving the number of chromosomes
What is the significance of the random assortment of chromosomes during metaphase in meiosis?
Introduction of genetic variation
During transcription, which component pairs with uracil on the DNA template strand?
Thymine
Where does mRNA exit the nucleus after formation?
Nuclear pore
What is the role of tRNA during translation?
Supplying mRNA to the ribosome
In which stage of meiosis do homologous chromosomes align at the cell equator?
Metaphase I
What is the significance of DNA replication during the cell cycle?
Maintaining the genetic information
What is the main difference between the daughter cells produced in mitosis and meiosis?
Daughter cells in mitosis are genetically identical, while in meiosis they are genetically different.
What is the genetic makeup of an organism known as?
Genotype
What is the primary function of chromosomes during cell division?
To carry genetic information
Which law states that when two homozygous organisms with contrasting traits are crossed, all individuals of the first generation will display the dominant trait?
Law of Dominance
What is the correct definition of alleles?
Variants of a gene occurring at the same locus on homologous chromosomes
What type of dominance occurs when neither allele completely masks the other, resulting in an intermediate phenotype?
Co-Dominance
In a genetic cross between a male (XY) and a female (XX), what is the probability of having a male offspring?
50%
Which principle states that an organism carries two alleles for a trait, with these alleles segregating during gamete formation?
Mendel's Principle of Segregation
Which genetic situation involves having more than two alternative forms of a gene at the same locus?
Multiple Alleles
When solving genetics problems, what typical format involves using letters to represent alleles and setting up Punnett squares?
Monohybrid Crosses
What enzyme is responsible for synthesizing a short RNA primer during DNA replication?
Primase
What technique did Rosalind Franklin and Maurice Wilkins use to study DNA's molecular structure?
X-ray diffraction
Which enzyme joins the Okazaki fragments on the lagging strand during DNA replication?
Ligase
Which nitrogenous base pairs with guanine in DNA?
Cytosine
What is the main significance of DNA replication for genetic diversity?
Contributes to evolution through genetic variation
During which phase of the cell cycle does DNA replication occur in eukaryotic cells?
Interphase
What is the primary role of helicases during DNA replication?
Break hydrogen bonds between complementary bases
What is the primary function of DNA in living organisms?
Genetic information storage and transmission
What is the function of DNA polymerases during DNA replication?
Add nucleotides to the growing DNA strand
Which two scientists proposed the double helix model of DNA in 1953?
James Watson and Francis Crick
What is the primary function of meiosis in terms of chromosome number?
Halving the number of chromosomes
During which stage of protein synthesis are amino acids linked together by peptide bonds?
Elongation
What is the role of tRNA molecules in translation during protein synthesis?
Attaching amino acids to ribosomes
Which phase of meiosis involves the formation of bivalents and crossing over of genetic material?
Prophase I
What happens to the nuclear membrane during Telophase I of meiosis?
It reforms around each set of chromosomes
What is the result of meiosis in terms of chromosome number?
The chromosome number is reduced from diploid to haploid
What contributes significantly to genetic variation within a species during meiosis?
Crossing over during Prophase II
What error in meiosis leads to an abnormal number of chromosomes in gametes?
Non-disjunction during Anaphase I or II
Which genetic condition can result from non-disjunction of chromosome pair 21?
Down Syndrome
Which stage of meiosis involves the reforming of nuclear envelopes around the chromosomes at each pole?
Telophase II
Where is ribosomal RNA (rRNA) primarily located within the cell?
Cytoplasm
What is the structure of RNA compared to DNA?
RNA is typically single-stranded, DNA forms a double helix
What is the primary role of messenger RNA (mRNA) in protein synthesis?
Serving as the template for protein synthesis
What is the function of tRNA during protein synthesis?
Transporting amino acids to ribosomes
Which form of RNA carries the genetic code from DNA to the cytoplasm in eukaryotic cells?
Messenger RNA (mRNA)
Which process results in the formation of four daughter cells that are genetically different from each other and from the parent cell?
Meiosis
In which process do homologous chromosomes pair up during the first division?
Metaphase in meiosis I
What concept refers to genetic forms of a gene occurring at the same locus on homologous chromosomes?
Alleles
Which term describes the physical appearance of an organism based on its genetic makeup?
Phenotype
What is the function of chromosomes during cell division?
Contain genetic information
Where is DNA primarily located within eukaryotic cells?
Nucleus
What is the main role of mitochondrial DNA (mtDNA) in cells?
Energy production
Which organelle, besides the nucleus, contains DNA in eukaryotic cells?
Mitochondria
What is the main function of chloroplast DNA in plants?
Energy production
In eukaryotic cells, where does DNA and proteins called histones come together to form chromosomes?
Nucleus
What is the main difference between complete dominance and incomplete dominance in terms of the phenotype?
Complete dominance masks the presence of one allele in the phenotype, while incomplete dominance creates an intermediate phenotype.
Which genetic concept involves having more than two alternative forms of a gene at the same locus?
Multiple Alleles
In the context of genetics, what does the Principle of Segregation propose?
Alleles segregate independently during gamete formation.
How do monohybrid crosses differ from dihybrid crosses?
Monohybrid crosses focus on one trait; dihybrid crosses focus on two traits.
What is the key distinction between codominance and incomplete dominance?
Codominance results in both traits blending together, while incomplete dominance exhibits fully expressed alleles.
What is the probability of a couple having a baby girl, given they already have three sons?
50%
Why are X-linked traits and disorders like haemophilia more commonly expressed in males?
Males have only one copy of the X chromosome
Which sex chromosome carries more genes and is commonly linked to genetic mutations and disorders?
X chromosome
What is the genetic makeup of a female in terms of sex chromosomes?
XX
In humans, what causes haemophilia, a sex-linked disorder?
Recessive allele on the X chromosome
What is the phenotypic ratio for males to females when considering sex determination in humans?
1:1
Which term refers to genetic disorders caused by genes located on the sex chromosomes?
Sex-linked inheritance
What type of mutations involve changes to non-coding DNA and do not affect the cell's structure or functioning?
Harmless Mutations
Which gene mutations occur on the X-chromosome and cause conditions like haemophilia and colour-blindness?
Sex-linked Mutations
What is a characteristic of sickle cell anaemia in terms of the genetic mutation?
Recessive Mutation
What type of mutation is beneficial if it enhances an organism's survival chances?
Useful Mutation
Which process involves altering the genetic makeup of an organism to enhance specific traits?
Genetic Engineering
Where do stem cells originate from in sources like embryonic stem cells, bone marrow, and umbilical cord blood?
Various Sources
What is the primary application of stem cells in medical treatments?
Repairing Heart Cells
Why are adult stem cells from sources like bone marrow less controversial than embryonic stem cells?
They Raise Fewer Ethical Concerns
Why do males with the Xh allele manifest haemophilia?
They lack a second X chromosome to provide a protective dominant allele.
Why can females be carriers of a disorder without showing symptoms?
They possess a second X chromosome with a normal allele.
Why is color-blindness particularly red-green color blindness considered a sex-linked disorder?
It is caused by a recessive allele located on the X chromosome.
Which genotype represents blood type B in humans?
IBIB
Why is blood type AB considered the result of co-dominance?
It is caused by the presence of two dominant alleles IA and IB.
How does DNA profiling compare to blood groups in paternity testing?
DNA profiling compares DNA sequences, unlike blood groups that look at blood types.
What is the significance of the Law of Independent Assortment in dihybrid crosses?
It describes how alleles of different genes separate independently during gamete formation.
Why are plant height and flower color considered independently inherited in dihybrid crosses?
Because genes for plant height and flower color are located on different chromosomes.
What is the main purpose of genetic engineering in the creation of GMOs?
To express desired traits in organisms
Which technique involves inserting the nucleus from a donor's body cell into an egg cell from which the nucleus has been removed?
Somatic cell nuclear transfer (SCNT)
Why does comparing blood groups of the mother, possible father, and child provide initial indications of paternity?
To establish a direct biological link between them
What is a significant benefit of paternity testing using DNA profiling compared to blood grouping?
Establishing a more conclusive link between father and child
How do genetically engineered seeds controlled by certain companies impact accessibility?
They raise questions about accessibility and rights
What ethical consideration arises from genetic engineering across different species?
The modification of genetic material
In paternity testing, why is DNA profiling considered more reliable evidence than blood grouping?
DNA profiles provide clearer indications of paternity
What role does cloning play in preserving endangered species?
It aids in maintaining genetic diversity
What is the purpose of setting up a Punnett square when studying genetic inheritance?
To visualize the possible combinations of alleles in offspring
In a pedigree diagram, what do shaded symbols typically represent?
Individuals expressing a particular trait
How can you determine if a trait is likely to be dominant or recessive by analyzing a pedigree diagram?
By observing if the trait appears in every generation (dominant) or skips generations (recessive)
What is the significance of using special symbols or shading patterns in sex-linked traits in pedigree diagrams?
To distinguish between affected males and females
What do you deduce about an individual's genotype if they express a recessive trait in a pedigree diagram?
They are homozygous recessive
In genetic lineage/pedigree diagrams, what does a vertical line leading downwards to other symbols represent?
Mating between two individuals
How can you determine the genotypes of parents based on their offspring's phenotypes in pedigree analysis?
By comparing the offspring's phenotype to known genotypes
What is the primary use of a Punnett square in genetics?
To visualize potential combinations of alleles in offspring
What type of mutations involve changes to non-coding DNA and do not affect the cell's structure or functioning?
Neutral mutations
Why are stem cells pivotal in medical treatments?
They can replace damaged cells in the body
Which gene mutation examples involve sex-linked gene mutations on the X-chromosome?
Haemophilia and Colour-blindness
What is the main focus of genetic engineering?
Modifying an organism's genetic makeup
What is the defining characteristic of harmful mutations?
Producing defective proteins
What is an example of a useful mutation?
Enhancing organism's survival chances
What is the cause of Albinism?
Recessive gene mutation preventing normal melanin development
What distinguishes harmful mutations from useful mutations?
Their impact on cell structure and functioning
What is the purpose of setting up a Punnett square in genetics?
To visually represent the possible combinations of alleles from parents
How can one distinguish between males and females in pedigree diagrams?
By using squares to represent females and circles for males
What does a vertical line leading downwards to other symbols represent in a pedigree diagram?
Mating between two individuals
How can one determine whether a trait in a pedigree diagram is likely dominant or recessive?
Based on how the trait appears in the lineage over generations
What does shaded symbols typically represent in pedigree diagrams?
Individuals expressing a particular trait
What is the genetic composition of a female carrier of color-blindness?
XBXB
Why do females with XhXh genotype manifest haemophilia?
Because they inherit two recessive Xh alleles
In pedigree diagrams, what do special symbols or shading patterns help differentiate?
Between affected males and females in sex-linked traits
What is the significance of analyzing pedigree diagrams in genetics?
To trace the inheritance of characteristics over multiple generations
Which blood type results from the expression of both IA and IB alleles?
AB
In regards to blood grouping, what blood type would a person with ii genotype have?
O
Why is the arrangement of possible gametes along the top and side of a Punnett square important?
To facilitate combining parental genotypes
What determines the sex of offspring when a male (XY) and a female (XX) have a genetic cross?
The genetic makeup of the male providing an X chromosome
Why does a male with genotype XbY have a higher chance of being color-blind?
Inheriting the recessive Xb allele on the Y chromosome
Why are X-linked traits and disorders more commonly expressed in males than in females?
Males have one copy of the Y chromosome
What is the explanation for females being carriers of haemophilia without displaying symptoms?
Possessing two X chromosomes with a normal allele
Why are blood types considered to demonstrate both co-dominance and complete dominance?
Due to the presence of multiple alleles controlling a single trait
What genetic disorder is characterized by the inability of blood to clot properly?
Haemophilia
'What characteristic controls blood grouping?'
Alleles
In sex-linked inheritance, where do most genetic disorders primarily originate from?
X chromosome
What is the phenotypic ratio for males to females in a genetic cross between a male (XY) and a female (XX)?
1:1
Why are X-linked traits passed on more commonly from mothers to sons?
Mothers can carry and transmit X-linked traits to sons
What is the main reason that haemophilia is more commonly expressed in males?
Males have only one copy of the X chromosome
What is the probability for a couple with three sons to have a baby girl, based on Mendelian genetics?
$\frac{1}{2}$
What technique is used in the creation of Genetically Modified Organisms (GMOs)?
CRISPR technology
Which process involves the creation of a genetically identical copy of an organism?
Cloning
What is a potential application of cloning mentioned in the text?
Therapeutic cloning for tissue repair
What ethical concerns are associated with genetic engineering as discussed in the text?
Commercial control over seeds
How does DNA profiling differ from blood grouping in paternity testing?
DNA profiling involves analyzing nucleotide sequences.
What is the significance of comparing blood groups in paternity testing?
Blood groups provide initial indications of paternity.
Where does paternity testing involve comparing the blood groups and DNA profiles?
Mother, possible father, and child
In paternity testing, what aspect of DNA is examined to determine paternity conclusively?
Frequency of alleles inherited by the child from both parents
What is the probability of a couple having a baby girl after having three sons, according to Mendelian genetics?
50%
Why are X-linked traits and disorders more commonly expressed in males than in females?
Females have more genes on the X chromosome.
What genetic disorder is characterized by the inability of blood to clot properly due to a deficiency in a clotting factor?
Haemophilia
Which sex chromosomes do females possess?
XX
What leads to an equal phenotypic ratio of 1:1 for males and females in human offspring?
Combination of XX during fertilization
What genetic cross results in an equal probability of having a male or female offspring in humans?
(XX) x (XY)
Which chromosome carries more genes and is commonly linked to genetic mutations and disorders?
X chromosome
What is the result of the genetic cross between a male (XY) and a female (XX)?
(XX)
What type of mutation often involves changes to non-coding DNA and does not affect the cell's structure or functioning?
Harmless Mutations
Which gene mutation leads to the production of faulty haemoglobin molecules in individuals with sickle cell anaemia?
Sickle Cell Anaemia gene mutation
What is the primary focus of genetic engineering as discussed in the text?
Modifying organism's genetic makeup for specific traits
When interpreting a pedigree, why is it crucial to understand the context of the trait such as whether it is autosomal or sex-linked?
To determine the genotype of the carriers
In genetic terms, what does Down syndrome result from?
An extra chromosome 21 in gametes
Which of the following traits would be considered a useful mutation if it enhances an organism's survival chances?
Freckles
What is the purpose of setting up a Punnett square in genetics?
To determine the possible genotypes of offspring
What is the classification of mutations that lead to changes in an organism's physical appearance or functioning due to incorrect or defective proteins?
Harmful Mutations
In a genetic cross involving hamsters with coat color and texture traits, what would be the genotype of a black hamster with a rough coat?
BBRR
Why is it significant to consider all possible genotypes when interpreting a pedigree based on the text?
'Harmless Mutations' involve non-coding DNA changes
In pedigree diagrams, what does a horizontal line connecting a square and a circle represent?
Mating between two individuals
How can one differentiate between dominant and recessive traits using pedigree diagrams?
By analyzing the shading of symbols
What can be inferred about a trait if it skips generations in a pedigree diagram?
It is likely to be recessive
In a Punnett square analysis, what do the 16 squares represent?
Offspring genotypes
What is the significance of shaded symbols in pedigree diagrams?
They signify individuals expressing a particular trait
How does understanding pedigree diagrams help genetic analysis?
By tracing the inheritance of traits over multiple generations
Why do females with the genotype XHXh not manifest haemophilia?
They have two X chromosomes with a normal allele.
What is the genetic composition of a normal female carrier of color-blindness?
XBXb
Why can a male who inherits the Xb allele have a higher chance of being color-blind?
The Xb allele is recessive in males.
What defines the blood type AB according to the provided text?
Presence of both IA and IB alleles.
Which blood type is expressed when an individual has the genotype ii?
Blood type O
In blood grouping, why does an individual express the O blood type?
They have double recessive ii alleles.
What does it mean when it is stated that IA and IB alleles are co-dominant?
IA and IB are equally expressed in phenotype when both are present.
Why are blood groups not considered conclusive evidence in paternity testing?
Many individuals share common blood types.
What is the primary difference between genetic engineering and cloning?
Genetic engineering involves altering an organism's genetic material, while cloning creates genetically identical copies of organisms.
How is DNA profiling different from blood grouping in paternity testing?
DNA profiling provides a more concrete indication of paternity, while blood grouping offers initial indications.
What are some ethical concerns associated with genetic engineering?
There are ethical issues related to embryonic stem cell research and genetic material modification across species.
What is a potential benefit of cloning for preserving species?
Cloning can be used to preserve endangered species.
How is paternity determined based on blood groups in paternity testing?
If the child's blood group could not be produced by the mother and the potential father, then he is not the father.
In what way does genetic engineering contribute to medical advancements?
Genetic engineering facilitates gene therapy for diseases like brain tumors and cystic fibrosis.
What is one of the concerns regarding genetic engineering's long-term impacts?
Long-term impacts include concerns about the regulation of genetically engineered seeds by specific companies.
Why is DNA profiling considered more reliable than blood grouping in establishing paternity?
DNA profiling compares DNA fragments inherited from each parent more accurately than blood groups.
Why can females be carriers of haemophilia without manifesting the disorder?
They possess two X chromosomes with a normal allele.
What is the genotype of a male individual who has normal vision but carries the allele for color-blindness?
XbY
Which blood type results from inheriting both alleles IA and IB?
Blood type AB
In a dihybrid cross, what does Mendel's Law of Independent Assortment state?
Genes on the same chromosome segregate independently.
What does the O blood type indicate in terms of an individual's genotype?
They carry two ii alleles.
Why does a female with the genotype XBXb not manifest color-blindness?
She inherited both X chromosomes with normal alleles.
What is the genetic makeup of a male in terms of sex chromosomes?
XY
In a genetic cross between a male (XY) and a female (XX), what is the probability of having a male offspring?
50%
Which sex chromosome carries more genes in humans?
X chromosome
What is the genetic makeup of a female in terms of sex chromosomes?
XX
What is the consequence of non-disjunction during meiosis?
Production of cells with abnormal chromosome numbers
Which genetic disorder is characterized by the inability of blood to clot properly?
Haemophilia
What does sex-linked inheritance refer to?
Genetic disorders linked to sex chromosomes
Why are X-linked traits and disorders more commonly expressed in males than in females?
Males have one X and one Y chromosome
What type of mutations involve changes to non-coding DNA that do not affect the cell's structure or functioning?
Useful Mutations
Which gene mutations are sex-linked and found on the X-chromosome?
Color-Blindness and Sickle Cell Anemia
In genetic engineering, what is the primary focus of modifying the genetic makeup of an organism?
Introducing Specific Traits
Which type of mutation may lead to genetic disorders like haemophilia and sickle cell anemia?
Harmful Mutations
What is the effect of a gene mutation causing the production of faulty hemoglobin molecules?
Sickle Cell Anemia
During DNA replication, what can result in gene mutations?
Omission of a Nucleotide
What type of mutation leads to advantageous genetic variation and contributes to natural selection?
Useful Mutations
What is the purpose of setting up a Punnett square in genetics?
To predict the potential genotypes of offspring
How are males and females represented in pedigree diagrams?
Males are represented by squares and females by circles
In a pedigree diagram, what does a horizontal line connecting two symbols represent?
Mating between individuals
What is the significance of analyzing pedigree diagrams to determine traits?
To trace the inheritance of characteristics over generations
How can one deduce whether a trait in a pedigree diagram is dominant or recessive?
By identifying whether the trait skips generations
What does a vertical line leading downwards to other symbols represent in a pedigree diagram?
Offspring resulting from a mating pair
Why might understanding pedigree diagrams be particularly useful for analyzing certain genetic conditions?
To trace the inheritance of traits over generations
Why might males be more frequently affected by sex-linked recessive traits according to pedigree analysis?
Because males have only one X chromosome, making it more likely for recessive traits to be expressed
What is the key difference between paternity testing using blood groups and DNA profiling?
Blood grouping provides a definitive answer, while DNA profiling may not be conclusive.
What is one of the ethical concerns associated with genetic engineering?
The uncertain long-term impacts on ecosystems and human health.
How does cloning contribute to improving food supply and preserving endangered species?
By breeding superior animals with desirable characteristics.
Why is DNA profiling considered more conclusive than blood grouping in paternity testing?
DNA comparisons can determine paternity accurately based on shared nucleotide sequences.
What is one of the potential drawbacks of genetic engineering highlighted in the text?
The control over genetically engineered seeds by specific companies.
How does genetic engineering play a role in producing cheaper and more effective pharmaceuticals?
By altering genetic material to create better drug formulations.
What makes DNA profiling a more reliable method for paternity testing than blood grouping?
DNA profiling provides direct comparisons of nucleotide sequences for accurate results.
What is a significant concern raised regarding the control of genetically engineered seeds by certain companies?
Potential monopolistic control over agriculture by specific companies.
What is the genetic makeup of a male in terms of sex chromosomes?
XY
Which sex is more commonly linked to genetic mutations and disorders due to the number of genes carried on its chromosomes?
Females
What is the probability of forming an XY offspring when a male (XY) and a female (XX) have a genetic cross?
50%
What is the chance of a couple having a baby girl after already having three sons, based on Mendelian genetics?
50%
Which chromosome carries the gene responsible for haemophilia, a sex-linked disorder?
X chromosome from the mother
Why are X-linked traits and disorders more commonly expressed in males than in females?
Females have two X chromosomes
What condition is characterized by the inability of blood to clot properly due to a deficiency in a clotting factor?
Haemophilia
Why can females be carriers of X-linked disorders without showing symptoms?
They have two X chromosomes with a normal allele.
Which statement accurately describes how color-blindness is inherited in males?
Men have a higher chance of being color-blind if they inherit the recessive allele on the X chromosome.
In terms of blood grouping, why is the O blood type only expressed when an individual has a specific genotype?
The O blood type is due to the presence of two recessive alleles.
What does it mean when alleles IA and IB are referred to as co-dominant in blood typing?
Both alleles are equally expressed in the AB blood type.
How does Mendel's Law of Independent Assortment apply to dihybrid crosses?
It explains how genes from different traits segregate independently during gamete formation.
What is the significance of the concept of multiple alleles in blood grouping?
It ensures that each individual has more than two alleles for a specific trait.
Why do males have a higher chance of expressing color-blindness compared to females?
Because males typically inherit an X chromosome with the recessive allele from their mothers.
What is the purpose of setting up a Punnett square in genetics?
To determine the phenotypes of the offspring
Which of the following best describes the role of pedigree diagrams in genetics?
Tracing inheritance patterns over generations
How do pedigree diagrams help determine if a trait is likely dominant or recessive?
By observing if the trait skips generations
For a practical example involving hamsters, what does a shaded symbol in a pedigree diagram typically represent?
Individuals expressing a specific trait
In genetics, what is the significance of males being more frequently affected in a sex-linked recessive trait like color-blindness?
As males only have one X chromosome
How does understanding pedigree diagrams aid in determining the genotypes of parents based on their offspring's phenotypes?
By tracing inheritance over generations
What convention helps quickly identify the sex of individuals in genetic lineages?
Use of different symbols for males and females
When analyzing traits within a pedigree diagram, what do shaded symbols typically indicate?
'Individuals expressing a particular trait'
What type of mutation involves changes to non-coding DNA and does not affect the cell's structure or functioning?
Harmless mutations
Which mutation type leads to changes in an organism's physical appearance or functioning due to incorrect or defective proteins?
Harmful mutations
What is the outcome of useful mutations if the genes are passed on?
They enhance survival chances
Which chromosome aberration occurs during Anaphase I and alters the chromosome number in gametes?
Down syndrome
What genetic engineering subset focuses on modifying the genetic makeup of an organism to introduce specific traits?
Genetic engineering
Where can stem cells be derived from, including embryonic stem cells and bone marrow?
Various sources like bone marrow, embryonic stem cells, and umbilical cord blood
What is the unique ability of stem cells that makes them pivotal in medical treatments?
Ability to develop into different types of body cells
Which genetic disorder results from a gene mutation causing the production of faulty haemoglobin molecules?
Sickle cell anaemia
What is the purpose of genetic engineering in creating GMOs?
To alter an organism's genetic material to express desired traits
In paternity testing, what method can provide initial indications of paternity based on blood groups?
Comparing blood groups of the mother, potential father, and child
What is a key benefit of cloning in terms of animal breeding?
Preserving endangered species
Why is DNA profiling considered a more reliable method for paternity testing compared to blood grouping?
DNA profiling provides conclusive evidence based on genetic similarities
What is a major ethical concern associated with genetic engineering?
Long-term impacts on ecosystems and human health
How does therapeutic cloning differ from artificial cloning?
Therapeutic cloning creates genetically identical copies for medical treatments
What makes DNA profiling a reliable method for confirming paternity compared to blood grouping?
DNA profiling examines genetic similarities between the potential father and child, providing conclusive evidence.
What is a significant advantage of GMOs in terms of food security?
Producing abundant and resilient crops.
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