388 Questions
Where is DNA primarily located in eukaryotic cells?
Nucleus
What are chromosomes made of in eukaryotic cells?
Histones and DNA
Which cellular organelle contains DNA that is essential for photosynthesis in plants?
Chloroplasts
What is the role of mitochondrial DNA (mtDNA) within the cell?
Energy production
In addition to the nucleus, where else can DNA be found in eukaryotic cells?
Mitochondria and chloroplasts
What was the primary role of Rosalind Franklin and Maurice Wilkins in the discovery of DNA's structure?
Studying DNA's molecular structure using X-ray diffraction
Which molecules make up a nucleotide in the structure of DNA?
Phosphate group, deoxyribose sugar, cytosine base
What holds the two strands of DNA together in the double helix structure?
Hydrogen bonds between nitrogenous bases
What is the main function of DNA?
Directing protein synthesis
During which phase of the cell cycle does DNA replication occur?
S phase
Where is messenger RNA (mRNA) formed?
In the nucleus
Which of the following RNA types is involved in transporting amino acids to the ribosomes during protein synthesis?
Transfer RNA (tRNA)
What is the function of ribosomal RNA (rRNA) in protein synthesis?
Facilitating assembly of amino acids into proteins
What makes RNA structurally different from DNA?
RNA has ribose sugar while DNA has deoxyribose sugar
During which stage of protein synthesis does the code within DNA get converted into functional proteins?
Translation
Which stage of protein synthesis involves the decoding of mRNA to synthesize a protein?
Translation
During transcription, what role does the template DNA strand play?
Acts as a template for mRNA synthesis
Where does meiosis occur in animals for the production of gametes?
Testes and ovaries
What happens during Anaphase I of meiosis?
Homologous chromosomes are pulled to opposite poles
What is the significance of crossing over during Prophase I of meiosis?
Increases genetic diversity
Which enzyme is responsible for unwinding the DNA double helix during DNA replication?
Helicase
What is the role of primase in DNA replication?
Synthesizing a short RNA primer
During DNA replication, where are nucleotides added to the growing DNA strand?
3' end of the strand
What is the function of ligase enzymes in DNA replication?
Joining Okazaki fragments on the lagging strand
Why is understanding DNA replication crucial for fields like genetics and medical research?
To support biological research and medical advancements
During which phase of meiosis II do centromeres divide, and spindle fibers pull the sister chromatids toward opposite poles?
Anaphase II
What is the main purpose of meiosis in sexual reproduction?
Produce genetically unique gametes
Which process introduces genetic diversity in meiosis through the exchange of genetic material between homologous chromosomes?
Crossing Over
What can result from non-disjunction during meiosis involving chromosome pair 21?
Down Syndrome
Which stage of meiosis ensures that the offspring have the correct diploid number of chromosomes?
Fertilization
Which of the following accurately describes the genetic differences between daughter cells in mitosis and meiosis?
Daughter cells in mitosis are genetically identical, while daughter cells in meiosis are genetically different.
What is the role of crossing over in genetic variability during cell division?
Crossing over occurs in meiosis to increase genetic variability among produced gametes.
In genetics, what are alleles?
Different forms of a gene that occur at the same locus on homologous chromosomes.
What is the genotype of an organism that is homozygous for a specific trait?
Two identical alleles for a specific trait.
What is the Law of Dominance in genetics?
When two homozygous organisms with contrasting traits are crossed, all F1 individuals will display the dominant trait.
In monohybrid crosses, what is the focus on?
Inheritance of single traits
Which principle states that each gamete carries only one allele for each trait?
Mendel's Principle of Segregation
What is the phenotype in incomplete dominance when red (RR) and white (rr) flower colors blend?
Pink flowers
What happens in complete dominance when plants with genotype Tt are crossed?
Only tall plants appear
What is the genetic makeup of a male that results in a male offspring in humans?
XY chromosome
Where is DNA primarily located in eukaryotic cells?
Nucleus
What is the main function of mitochondrial DNA (mtDNA) within the cell?
Plays a critical role in energy production within the cell
Which cellular organelle contains DNA that is essential for photosynthesis in plants?
Chloroplasts
What role does histone proteins play in relation to DNA within the cell nucleus?
Compacting and organizing DNA into chromosomes
In addition to the nucleus, where can DNA also be found in eukaryotic cells?
Mitochondria
What is the significance of DNA replication in ensuring genetic continuity?
It ensures each new cell receives a complete set of DNA.
Which phase of the cell cycle is critical for DNA replication to occur?
Interphase
What is the primary function of DNA in living organisms?
To store and transmit genetic information
Which pairing of nitrogenous bases is crucial for accurate DNA replication?
Cytosine with thymine
What role do regulatory regions in DNA play in gene expression?
Regulate when and how much protein is produced
Where is messenger RNA (mRNA) formed?
In the nucleus
What is the function of transfer RNA (tRNA) in protein synthesis?
Interpreting the genetic code carried by mRNA
What is the primary role of ribosomal RNA (rRNA) in protein synthesis?
Assembling amino acids into proteins within ribosomes
What is the main purpose of meiosis in sexual reproduction?
To reduce the chromosome number in gametes
In which form does RNA exist mainly within ribosomes?
Ribosomal RNA (rRNA)
What occurs during the Elongation phase of protein synthesis?
Addition of amino acids to form a polypeptide chain
Which stage of meiosis involves homologous chromosomes aligning at the cell equator?
Metaphase I
What distinguishes RNA from DNA structurally?
Single-stranded nature
What is the primary role of Transfer RNA (tRNA) molecules during protein synthesis?
Carry amino acids and bind to mRNA codons
Where does transcription, the first stage of protein synthesis, primarily occur?
Nucleus
What is the role of primase in DNA replication?
Synthesizing DNA primers
How does DNA polymerase ensure the fidelity of DNA replication?
Proofreading and repairing errors in base pairing
During DNA replication, what is the significance of adding nucleotides in a 5' to 3' direction?
It ensures complementary base pairing
What is the purpose of ligase enzymes in DNA replication termination?
Joining Okazaki fragments on the lagging strand
Why is it essential for helicases to break hydrogen bonds in DNA replication?
To enable the unwinding of the DNA double helix
What is the main purpose of Meiosis II in the process of meiosis?
Formation of haploid daughter cells
Which phase of meiosis involves the division of centromeres and the pulling of sister chromatids towards opposite poles?
Anaphase II
What is the significance of crossing over during Prophase I of meiosis?
Creating genetically unique gametes
In humans, non-disjunction during meiosis can lead to which condition?
Down Syndrome
Which process ensures that after fertilization, offspring have the correct diploid chromosome number?
Reduction division
What is the role of meiosis in the life cycle of organisms?
To ensure genetic diversity and reproduction
What distinguishes metaphase I in meiosis from metaphase in mitosis?
Homologous chromosome pairs line up on the equator
Which concept explains why some individuals express a dominant trait despite being heterozygous for a specific characteristic?
Law of Dominance
What is the term for an organism that has two different alleles for a specific trait?
Heterozygous
In genetics, what do alleles refer to?
Different forms of a gene at the same locus on homologous chromosomes
What is the main difference between complete dominance and incomplete dominance?
In complete dominance, one allele is fully expressed over another, while in incomplete dominance, neither allele is completely dominant.
In co-dominance, what happens to the alleles in the pair?
Both alleles are equally expressed, leading to a blend of traits.
What does Mendel's Principle of Segregation explain in genetics?
How alleles segregate during the formation of gametes and ensure genetic diversity.
Which statement best describes the genetic cross between a male (XY) and a female (XX) in humans?
It leads to an equal probability of having a male or female offspring.
What is the significance of understanding the principles of incomplete dominance and co-dominance in genetics?
It helps interpret genetic crosses and predict inheritance patterns beyond those of complete dominance.
Where is DNA primarily located within eukaryotic cells?
Nucleus
What is the role of mitochondrial DNA (mtDNA) within the cell?
Energy production
Which cellular structure is responsible for compacting DNA to fit within the nucleus?
Histones
In plants, which organelle contains DNA essential for photosynthesis?
Chloroplast
Which type of cell inherits mitochondrial DNA maternally?
Gametes
What is the primary function of DNA in living organisms?
Stores and transmits genetic information
During DNA replication, what is the role of primase?
Synthesizes RNA primers for DNA polymerase
Which nitrogenous base pairs with cytosine in DNA?
Guanine
Where does DNA replication primarily take place in eukaryotic cells?
Nucleus
What is the significance of adenine pairing with thymine in DNA replication?
Ensures accurate copying of DNA
What is the role of tRNA during translation?
Attaching to mRNA at the ribosome
In meiosis, what occurs during Prophase I?
Chromosomal condensation and crossing over
What happens during the termination phase of protein synthesis?
Ribosome reaches a stop codon
Where does meiosis primarily occur in plants for the production of spores and gametophytes?
Anthers and ovules
During transcription, what is the function of the template DNA strand?
Pairing with RNA nucleotides
What is the role of primase in DNA replication?
Synthesizing a short RNA primer
Which enzyme is responsible for unwinding the DNA double helix during DNA replication?
Helicase
What is the significance of DNA replication for genetic diversity?
Leads to mutations causing genetic diversity
During DNA replication, where are nucleotides added to the growing DNA strand?
3' end of the newly forming strand
In DNA profiling, what does a match between bands in an evidence sample and a reference sample suggest?
The samples are from the same source
Where is mRNA formed, and what is its primary function?
Formed in the nucleus; carries the genetic code from DNA to the cytoplasm for protein synthesis
Which of the following nitrogenous bases is unique to RNA and pairs with adenine (A)?
Uracil (U)
What is the primary role of tRNA during protein synthesis?
Transporting amino acids to the ribosome in correct order for protein synthesis
What is the primary function of rRNA within the cell?
Assisting in the structure and function of ribosomes
Which stage of protein synthesis involves the conversion of genetic information encoded in DNA into proteins?
Translation
What happens during prophase in meiosis that distinguishes it from prophase in mitosis?
Homologous chromosomes pair up.
Which genetic concept relates to different forms of a gene found at the same locus on homologous chromosomes?
Alleles
What type of cells result from the second division in meiosis (Meiosis II)?
Haploid genetically varied cells
Which term refers to an organism with two different alleles for a specific trait?
Heterozygous
What differentiates telophase in meiosis I from telophase in mitosis?
Movement of whole chromosomes to opposite poles in meiosis I.
What is the difference between complete dominance and incomplete dominance?
Complete dominance results in the heterozygous individual showing only one trait, while incomplete dominance shows both traits simultaneously.
How does multiple alleles differ from other types of genetic inheritance?
In multiple alleles, an individual can have more than two alternative forms of a gene at the same locus, while in other types only two forms are possible.
Which genetic concept explains why offspring have an equal probability of being male or female in humans?
Sex Determination Principle
In a monohybrid cross involving a plant with genotype Tt for stem height (T = tall, t = short), what is the phenotypic ratio of the offspring according to Mendel's observations?
3:1 tall to short
What is the genetic basis for the AB blood type in humans?
Co-dominance of A and B alleles
What happens to chromosomes during Anaphase II of meiosis?
Centromeres divide, and sister chromatids move to opposite poles
What genetic material exchange mechanism occurs during Prophase I of meiosis?
Crossing over
Which condition results from non-disjunction involving chromosome pair 21 during meiosis?
Down Syndrome
How does meiosis contribute to genetic variation within a species?
By random assortment of chromosomes during division
What is the outcome of Meiosis II in terms of the number of daughter cells produced?
Four haploid daughter cells
Which phase of the cell cycle does DNA replication primarily occur in?
S phase
What is the main function of DNA polymerase in DNA replication?
Adding nucleotides to the growing DNA strand
How are the two strands of DNA held together in the double helix structure?
Hydrogen bonds between nitrogenous bases
During which stage of the cell cycle does DNA replication take place in eukaryotic cells?
Interphase
What is the significance of accurate DNA replication during cell division?
It prevents mutations in the genetic code
Where is DNA primarily located within eukaryotic cells?
Nucleus
What is the main function of mitochondrial DNA (mtDNA) within the cell?
Produce energy
What is the primary role of chloroplast DNA in plants?
Convert light energy to chemical energy
Which cellular organelle contains DNA that is essential for photosynthesis in plants?
Chloroplast
Inheritance of mitochondrial DNA (mtDNA) is primarily through which parent?
Maternal inheritance
Where is ribosomal RNA (rRNA) primarily located within the cell?
Cytoplasm
What is the primary function of messenger RNA (mRNA) in protein synthesis?
Carrying the genetic code from DNA to the cytoplasm
Which nitrogenous base is unique to RNA and replaces thymine found in DNA?
Uracil (U)
What is the structure of RNA, compared to DNA?
Has uracil as a nitrogenous base instead of adenine
In protein synthesis, what is the role of transfer RNA (tRNA)?
Transporting amino acids to the ribosome during protein synthesis
What is the role of primase in DNA replication?
Synthesizing the RNA primer necessary for DNA polymerases
What is the significance of ligase enzymes in DNA replication termination?
Joining Okazaki fragments on the lagging strand
What is the main function of DNA polymerases during DNA replication?
Adding nucleotides to the growing DNA strand in a 5' to 3' direction
Which enzyme is responsible for unwinding the DNA double helix during DNA replication?
Helicase
Why is it essential for DNA polymerases to have proofreading abilities during DNA replication?
To correct errors or mismatches in base pairing
What is the role of tRNA molecules during translation?
Carry specific amino acids and have an anticodon
During meiosis I, what occurs during prophase that contributes to genetic diversity?
Crossing over and exchange of genetic material
Which nitrogenous bases pair up during mRNA formation in transcription?
Adenine pairs with uracil, cytosine pairs with guanine
What occurs during the termination phase of protein synthesis?
Ribosome reaches a stop codon on the mRNA
Where does meiosis occur in plants for the production of spores and gametophytes?
Anthers and ovules
What is the significance of reducing the chromosome number from diploid (2n) to haploid (n) during meiosis?
To ensure the offspring have a correct diploid number of chromosomes after fertilization.
What is the main purpose of non-disjunction in meiosis?
To separate homologous chromosomes incorrectly, leading to abnormal chromosome numbers.
Which process introduces genetic diversity during meiosis through the exchange of genetic material between homologous chromosomes?
Crossing over
What distinguishes the outcome of Meiosis II from Meiosis I in terms of daughter cells produced?
Meiosis II produces four haploid daughter cells.
How does non-disjunction during meiosis relate to abnormal chromosome numbers?
Non-disjunction can result in gametes with an abnormal number of chromosomes.
What type of inheritance is defined by both alleles being fully expressed in the phenotype?
Co-dominance
In a monohybrid cross, what is the phenotypic outcome of incomplete dominance?
A blend or intermediate phenotype appears
Which principle explains that an organism possesses two alleles for any trait and these alleles segregate during gamete formation?
Mendel's Principle of Segregation
What is a distinguishing characteristic of complete dominance in terms of phenotypic expression?
Only the dominant trait is visible
In a monohybrid cross, what is the expected phenotypic ratio for complete dominance?
3:1
Which phase of mitosis involves the splitting of centromeres and movement of chromatids to opposite poles?
Anaphase
What is the genotype of an organism that is heterozygous for a specific trait?
Tt
Which genetic concept describes a situation where the dominant allele completely masks the expression of the recessive allele?
Complete dominance
Where does DNA primarily exist in eukaryotic cells when it is not condensed into chromosomes during cell division?
Chromatin
Where is DNA primarily located within eukaryotic cells?
Nucleus
What is the function of mitochondrial DNA (mtDNA) in eukaryotic cells?
Energy production
Which cellular organelle contains DNA essential for photosynthesis in plants?
Chloroplast
What is the role of histones in relation to DNA?
Organizing and compacting DNA
Which characteristic distinguishes mitochondrial DNA from nuclear DNA?
Plays a role in energy production
What is the primary function of DNA?
Storing and transmitting genetic information
During DNA replication, where does the process primarily take place?
Nucleus
Which nitrogenous base pairs with cytosine in DNA?
Adenine
What critical event occurs during the S phase of the cell cycle?
DNA replication
Which scientists were directly responsible for proposing the double helix model of DNA?
James Watson and Francis Crick
What is the genetic makeup of an organism that is homozygous for a specific trait?
Two identical alleles
Which concept in genetics explains why dominant alleles are expressed in the phenotype?
The Law of Dominance
During which stage of meiosis do whole chromosomes move to opposite poles instead of chromatids?
Anaphase I
Which term describes different forms of a gene located at the same locus on homologous chromosomes?
Alleles
What is the outcome of crossing two heterozygous organisms for a particular trait according to the Law of Dominance?
All offspring show the dominant trait.
In a monohybrid cross involving incomplete dominance, what is the phenotypic ratio expected among the offspring?
1:2:1
What is the main difference between transcription and translation in protein synthesis?
Transcription creates mRNA from DNA, while translation synthesizes proteins from mRNA.
When two plants with pink flowers (Rr) resulting from incomplete dominance are crossed, what is the expected phenotypic ratio of their offspring?
1 red: 2 pink: 1 white
What is the role of primase in DNA replication?
Synthesizes a short RNA primer
During protein synthesis, what molecule carries specific amino acids and has a set of three nucleotides known as an anticodon?
tRNA
Which genetic concept explains the inheritance pattern where both alleles of a gene pair are fully expressed without blending in co-dominance?
Co-dominance
What is the significance of crossing over during Prophase I of meiosis?
It contributes to genetic diversity.
During DNA replication, which enzyme breaks the hydrogen bonds between complementary bases to unwind the DNA double helix?
Helicase
If a plant with genotype TT for stem height (complete dominance) is crossed with a plant having genotype Tt, what is the expected phenotypic ratio of their offspring?
4 tall: 0 short
In DNA replication, what is the significance of DNA polymerases' proofreading abilities?
Correcting errors or mismatches in base pairing
Which phase of meiosis ensures the reduction of the chromosome number by half?
Anaphase I
In a genetic cross involving co-dominance for blood type where a person with IAIB genotype mates with a person with IAi genotype, what blood types can their offspring inherit?
AB, A, B
Where does meiosis primarily occur in plants for the production of spores and gametophytes?
Anthers and ovules
What happens during the termination stage of DNA replication?
Joining Okazaki fragments on the lagging strand
What is the primary function of ligase enzymes in DNA replication?
Joining Okazaki fragments on the lagging strand
Where is mRNA formed and what is its primary function?
Formed in the nucleus; primary function is to carry genetic code from DNA to the cytoplasm
What are the components of a RNA nucleotide?
Ribose sugar, phosphate group, uracil base
What is the primary role of rRNA in protein synthesis?
Facilitates the assembly of amino acids into proteins
During which phase of meiosis does crossing over occur?
Prophase I
Which type of RNA is involved in transporting amino acids to the ribosome during protein synthesis?
tRNA
What distinguishes RNA from DNA in terms of structure?
RNA contains uracil base; DNA contains thymine base
What is the consequence of non-disjunction during Anaphase I of meiosis?
Gametes with abnormal chromosome numbers are produced.
Which stage of meiosis marks the division of centromeres and movement of sister chromatids to opposite poles?
Anaphase II
What genetic condition results from non-disjunction of chromosome pair 21 during meiosis?
Down Syndrome
Which key process in meiosis ensures that gametes have different combinations of chromosomes?
Random assortment during Anaphase II
In a monohybrid cross involving a hamster with a black coat color and rough coat texture, if a heterozygous black, homozygous rough hamster (BbRR) is crossed with a homozygous black, homozygous smooth hamster (BBrr), what is the expected phenotypic ratio of the offspring?
All black with rough coats
In a pedigree diagram, what does a vertical line leading downwards to other symbols represent?
Offspring of the mating couple
How can one determine whether a trait is likely dominant or recessive in a pedigree diagram?
By observing if the trait skips generations
What is the genetic makeup of a male in terms of sex chromosomes?
XY
What do shaded symbols typically represent in pedigree diagrams?
Individuals expressing a particular trait
In humans, why are X-linked traits and disorders more commonly expressed in males than in females?
Males have only one X chromosome.
When analyzing pedigree diagrams, how can one deduce whether a trait is dominant or recessive?
By deducing if the trait appears in every generation or skips generations
Which sex chromosome carries more genes in humans?
X chromosome
What is the primary characteristic of haemophilia as a sex-linked disorder?
Decreased blood clotting ability
What is the significance of using pedigree diagrams when tracing traits over multiple generations?
To determine how certain traits are passed down through families
In sex-linked traits depicted in pedigree diagrams, what do special symbols or shading patterns help differentiate between?
Affected and unaffected females
In a genetic cross between a male (XY) and a female (XX), what is the probability of having a female offspring?
50%
What does a horizontal line connecting a square and a circle represent in pedigree diagrams?
Mating between two individuals
Why are X-linked traits more commonly linked to genetic mutations and disorders compared to Y-linked traits?
Y chromosome carries fewer genes
What is the genetic makeup of a female in terms of sex chromosomes?
XX
What leads to an equal phenotypic ratio of 1:1 for males and females in humans?
Equal contribution of X and Y chromosomes from parents
Which type of mutation leads to changes in an organism's physical appearance or functioning due to incorrect or defective proteins?
Harmful Mutations
What is a characteristic feature of Sickle Cell Anaemia?
Autosomal disease
What is the primary focus of Genetic Engineering?
Modifying genetic makeup of organisms
Which type of stem cells have raised ethical concerns due to their use in medical treatments?
Embryonic stem cells
What can result from a gamete with an abnormal number of chromosome 21?
Down syndrome
What is the role of Chromosome Aberrations during cell division?
Altering chromosome numbers in gametes
Which type of mutations are considered beneficial if they enhance an organism's survival chances?
Useful Mutations
What distinguishes Albinism as a genetic condition?
Recessive gene mutation
How does DNA profiling differ from blood grouping in paternity testing?
DNA profiling examines nucleotide sequences of DNA fragments, while blood grouping looks at blood types.
What is a potential limitation of using blood grouping for paternity testing?
Many men may share the same blood group.
In cloning, which technique involves inserting the nucleus from a donor's body cell into an egg cell?
Somatic cell nuclear transfer (SCNT)
What is a significant ethical consideration associated with genetic engineering?
Access to genetically engineered seeds by certain companies
How does cloning contribute to preserving endangered species?
By creating genetically identical copies of endangered individuals
What is a primary benefit of GMOs in agriculture?
Increasing food security through resilient crops
What distinguishes therapeutic cloning from other cloning techniques?
It aims to create tissues or organs for medical purposes.
Why is DNA profiling considered more reliable than blood grouping in paternity testing?
DNA profiling compares nucleotide sequences for a clear indication of paternity.
Why do males with the Xh allele manifest haemophilia?
They have the Xh allele on their Y chromosome.
Inheritance of color-blindness differs between males and females mainly due to:
The presence of the recessive Xb allele on the Y chromosome in males.
What is the main reason females are less likely to manifest color-blindness compared to males?
Presence of a dominant allele on their X chromosomes.
Why can't haemophiliac females have the genotype XHXH?
The genotype XHXH is incompatible with the expression of haemophilia.
Which blood type arises when an individual inherits both IA and IB alleles?
Blood type AB
What would be the blood type of an individual with the genotype ii?
Blood type O
How does Mendel's Law of Independent Assortment apply to dihybrid crosses?
It explains how alleles of different genes separate independently during gamete formation.
Why are blood groups not conclusive for paternity testing?
DNA profiling provides more reliable results than blood groups.
What is the purpose of Punnett squares in genetics?
To predict the possible genotypes of offspring from a genetic cross
In a Punnett square, what do the letters along the top and side represent?
Different possible gametes from each parent
What information can be derived from a pedigree diagram?
Whether a trait is likely dominant or recessive
How are males and females typically represented in pedigree diagrams?
Males as squares and females as circles
When analyzing a pedigree, what does the presence of a trait in every generation suggest?
The trait is likely dominant
In a pedigree, how can carriers of a recessive trait be identified?
By being unshaded but having affected relatives
What do shaded symbols usually represent in a pedigree diagram?
"Affected" individuals expressing a particular trait or condition
What does the vertical line leading downwards to other symbols represent in pedigree diagrams?
Parent-offspring relationship
What is the probability of a couple having a baby girl after already having three sons?
50%
In humans, which parent determines the sex of the offspring based on the chromosomes they provide?
The male
Why are X-linked traits and disorders more commonly expressed in males than in females?
Males have one X and one Y chromosome
What is the term for the genetic disorders caused by genes located on the sex chromosomes?
Sex-linked inheritance
Which chromosome carries more genes in humans, leading to a higher incidence of genetic mutations and disorders?
X chromosome
What is the main characteristic of haemophilia as a sex-linked disorder?
Deficiency in clotting factor
Why are X-linked traits and disorders less common in females?
Females have two copies of the X chromosome
What distinguishes between harmless, harmful, and useful mutations based on their effects on the DNA?
The impact of the mutation on the cell or organism
What is a characteristic feature of useful mutations that distinguishes them from harmful mutations?
They enhance the organism's survival chances.
In genetic engineering, what is the primary focus of modifying the genetic makeup of an organism?
Enhancing or introducing specific traits
Which type of mutation involves changes to the DNA that do not affect the cell's structure or functioning?
Harmless mutations
What is a key consideration when interpreting a pedigree to identify carriers of recessive traits?
Understanding whether the trait is autosomal or sex-linked
Which type of mutation can lead to genetic disorders like haemophilia and sickle cell anaemia?
Harmful Mutations
What distinguishes between harmless and harmful mutations in terms of their impact on the organism?
The effect on protein production and physical appearance
What differentiates between stem cell sources in terms of ethical concerns in medical treatments?
Bone marrow stem cells are less controversial and widely used
Why is a male more likely to manifest haemophilia compared to a female carrier with the Xh allele?
Males have only one X chromosome, so they lack a second X chromosome for protection.
What determines the blood type AB in humans?
Co-dominance of alleles IA and IB resulting in a combined phenotype.
How does the genotype ii manifest as blood type O in humans?
Through a double recessive genotype lacking alleles IA and IB.
In Mendel's pea plants, how do genes for plant height and flower color inherit independently?
Due to genes being located on different chromosomes.
Why do males have a higher chance of being color-blind compared to females?
Color blindness is a recessive trait carried by the X chromosome, which males possess only one of.
What does it mean when two alleles are co-dominant in an individual's phenotype?
Both alleles are expressed independently in the phenotype.
Why is DNA profiling considered more reliable than blood grouping for paternity testing?
Blood groups are not unique to individuals, leading to inconclusive results.
What makes parents with blood group B (IBi each) capable of producing a child with blood group O?
'O' blood type arises from both parents contributing recessive 'i' alleles.
Which method provides a more definitive indication of paternity compared to blood grouping in paternity testing?
Comparing DNA profiles
What is a potential limitation of using blood grouping alone for paternity testing?
Many men may have the same blood group
In cloning, what technique involves inserting the nucleus from a donor's body cell into an egg cell?
Somatic cell nuclear transfer (SCNT)
Why is it important to consider ethical implications in genetic engineering?
To balance benefits and potential negative consequences
What distinguishes therapeutic cloning from reproductive cloning?
The purpose of tissue repair in therapeutic cloning
How does genetic engineering contribute to medical advancements?
By producing cheaper pharmaceuticals
What is the purpose of comparing the blood groups in a paternity test?
To provide initial indications of paternity
What type of mutation involves permanent changes to the DNA of a cell?
Gene mutations
Which genetic disorder is caused by a gene mutation resulting in the production of faulty haemoglobin molecules?
Sickle cell anaemia
What is the primary focus of Genetic Engineering within the field of Biotechnology?
Enhancing specific traits in organisms
What is a potential outcome of useful mutations if the genes are passed on?
Increased genetic variation
Which type of mutation involves alterations in DNA that do not affect the functioning of the cell?
Chromosomal mutations
What is the significance of considering whether a trait is autosomal or sex-linked when interpreting a pedigree?
Understanding the mode of inheritance
Which type of mutation leads to changes in an organism's physical appearance due to defective proteins?
Harmful mutations
What distinguishes harmful mutations from useful mutations in their effects on organisms?
Benefit to survival chances
What is the probability of a genetic cross between a male (XY) and a female (XX) resulting in a female offspring?
50%
Which sex chromosome carries more genes in humans and is commonly linked to genetic mutations and disorders?
X chromosome
In humans, which gender tends to more commonly express X-linked traits and disorders due to having only one copy of the X chromosome?
Males
What genetic disorder is characterized by the inability of blood to clot properly due to a clotting factor deficiency?
Haemophilia
Which allele on the X chromosome causes haemophilia, a sex-linked disorder?
Xh
What is the phenotypic ratio of males to females resulting from the genetic cross between a male (XY) and a female (XX)?
1:1
What gender provides either an X or a Y chromosome during gamete formation in humans?
Male
What is the chance of a couple, who already has three sons, having a baby girl according to Mendelian genetics?
50%
What is the purpose of setting up a Punnett square in genetics?
To visualize the possible combinations of alleles in offspring
In a practical example involving hamsters with coat color and coat texture, what information can be obtained from a Punnett square?
Offspring's genotypes and phenotypes
How are individuals with specific traits usually represented in pedigree diagrams?
Through shaded symbols
What is a common misconception about sex-linked traits and pedigree diagrams?
Sex-linked traits are always recessive
Why is it crucial to identify whether a trait is dominant or recessive in pedigree analysis?
To predict the likelihood of disease inheritance
What can be inferred if a trait present in a pedigree diagram skips generations?
The trait is recessive
How does analyzing pedigree diagrams aid in understanding genetic inheritance?
By tracing the passage of traits through generations
What role do shaded symbols play in pedigree diagrams?
To indicate individuals expressing specific traits
Why do females have a higher chance of being carriers for sex-linked disorders like haemophilia compared to males?
Females have two X chromosomes providing a protective dominant allele.
In blood grouping, why does an individual express blood type O?
By having only the i allele with no IA or IB allele.
What is the genetic basis for individuals with AB blood type in humans?
Inheriting two co-dominant IA and IB alleles.
How do males have a higher risk of color-blindness compared to females?
Males have only one X chromosome, so if they inherit the Xb allele, they will be color-blind.
Why are dihybrid crosses based on Mendel's Law of Independent Assortment?
Because the alleles of different genes segregate independently during gamete formation.
What is the main reason for using DNA profiling over blood grouping in paternity testing?
DNA profiling compares unique patterns while blood grouping has commonalities.
How does the inheritance pattern differ between haemophilia and color-blindness?
Haemophilia is inherited through autosomal chromosomes, while color-blindness is sex-linked.
How does the concept of co-dominance manifest in blood types?
Both IA and IB dominate over the i allele in blood type AB individuals.
What 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)
In paternity testing, why is DNA profiling considered more reliable than blood grouping?
DNA profiling provides a more conclusive method
What is the primary concern raised regarding genetic engineering?
Ethical, health, and environmental implications
How can paternity be determined using blood groups?
By comparing blood groups of mother, father, and child
What distinguishes therapeutic cloning from other cloning techniques?
Creating genetically identical copies for tissue repair
Why do some ethical debates in genetic engineering focus on embryonic stem cell research?
Potential misuse of genetic information
What is the significance of Dolly the sheep in cloning?
First mammal cloned from an adult cell
What distinguishes harmless mutations from harmful mutations?
Harmful mutations affect the organism's physical appearance.
Which gene mutation type contributes to advantageous genetic variation?
Useful mutations
What is the main focus of genetic engineering?
Modifying the genetic makeup of an organism
What occurs in an autosomal disease like sickle cell anaemia?
A recessive gene mutation causes production of abnormal red blood cells.
How do useful mutations differ from harmful mutations?
Harmful mutations enhance survival chances.
What is the significance of considering all possible genotypes when interpreting a pedigree?
It helps in identifying carriers of recessive traits.
In genetic engineering, what does the creation of genetically modified organisms involve?
Enhancing or introducing specific traits through genetic manipulation.
What is the genetic makeup of a male individual?
XY
Why are X-linked traits and disorders more commonly expressed in males?
Because males have one copy of the X chromosome.
What is the phenotypic ratio of males to females in offspring when a male (XY) and a female (XX) have a child?
1:1
In humans, what can result from a deficiency in a clotting factor due to a sex-linked disorder?
Haemophilia
Why do X-linked traits and disorders more commonly affect males even though females have two X chromosomes?
Males have only one copy of the X chromosome.
What is the genetic makeup of an individual with hemophilia?
XhXh
How does sex determination work in humans based on Mendelian genetics?
It leads to an equal probability of having male or female offspring.
Why do males have a higher incidence of X-linked traits and disorders compared to females?
Males have fewer X chromosomes than females.
What is the purpose of setting up a Punnett square in genetic analysis?
To visualize the possible genotypes of offspring
In a Punnett square, how do you represent different alleles from each parent?
Along the top and side of the square
How do pedigree diagrams help in understanding genetic lineages?
By tracing the inheritance of characteristics over generations
What do shaded symbols typically represent in pedigree diagrams?
Individuals expressing recessive traits
How can one determine whether a trait is dominant or recessive using pedigree diagrams?
By checking if it skips generations
What is the significance of using squares and circles to represent males and females in pedigree diagrams?
To help identify the sex of individuals quickly
Why is it important to assign probable genotypes to individuals in pedigree analysis?
To identify carriers of recessive traits
What is your favourite food?
Pizza
Why can females be carriers of haemophilia without showing any symptoms?
They have two X chromosomes with the normal allele.
What is the genotype of a color-blind female?
XbXb
How are the alleles IA and IB related in blood typing?
They are co-dominant to each other.
In blood grouping, what does the O blood type indicate about an individual's genotype?
They lack both IA and IB alleles.
What genetic concept is demonstrated when traits like plant height and flower color are inherited independently in dihybrid crosses?
Independent assortment
Why can't a male be a carrier of a sex-linked disorder like haemophilia or color-blindness?
Males inherit only one X chromosome from their mothers.
What is the phenotype of an individual with the genotype TtPp in a dihybrid cross?
Tall with purple flowers
What does it mean when it's stated that IA and IB are co-dominant alleles in blood typing?
They occur together only in AB blood type individuals.
What is the primary purpose of genetic engineering in creating GMOs?
To enhance medical treatments
Which process involves creating a genetically identical copy of an organism?
Gene therapy
What distinguishes DNA profiling from blood grouping in paternity testing?
DNA profiling relies on similarities in nucleotide sequences
In paternity testing, what does it indicate if 50% of the child's DNA fragments match those of a potential father?
The potential father is likely the biological father
What are some ethical concerns associated with genetic engineering?
Control over genetically engineered seeds by certain companies
How do identical twins normally form?
As a natural occurrence
In the genetic cross between a male (XY) and a female (XX), what is the probability of forming a male offspring?
50%
Why are X-linked traits and disorders more commonly expressed in males than in females?
Males have only one copy of the X chromosome.
Which gender is more likely to manifest haemophilia due to having only one copy of the X chromosome?
Males
What is the impact of males having one copy of the X chromosome on the expression of X-linked traits and disorders?
Increased expression in males
What distinguishes harmful mutations from useful mutations?
Useful mutations enhance an organism's survival chances.
Which type of gene mutation causes albinism?
Recessive gene mutation
What type of mutation leads to changes in an organism's physical appearance or functioning?
Harmful mutation
What is the main focus of genetic engineering in biotechnology?
Modifying genetic makeup of organisms
Where do stem cells for medical treatments primarily come from?
Adult stem cells from bone marrow
What causes Sickle Cell Anaemia?
An autosomal gene mutation
What is a characteristic of harmless mutations?
Often involve non-coding DNA.
How do harmful mutations differ from useful mutations?
Harmful mutations result in changes in the cell's structure or functioning.
What is the purpose of setting up a Punnett square in genetics?
To arrange possible genotypes of offspring
How are males and females typically represented in pedigree diagrams?
Males as squares and females as circles
Which step helps determine whether a trait in a pedigree diagram is likely dominant or recessive?
Step 1: Analyzing genotypes of specific individuals
What is the significance of shading in pedigree diagrams?
It differentiates between affected and unaffected individuals
Why do males tend to be more affected by sex-linked recessive traits in pedigree diagrams?
Because the gene for the trait is located on the X chromosome
In a pedigree diagram, what does a vertical line leading downwards from two symbols represent?
Their shared offspring
What is the key purpose of analyzing pedigree diagrams in genetics?
To trace the inheritance of characteristics over generations
Why is it important to identify whether a trait is dominant or recessive when analyzing pedigree diagrams?
To predict how traits will be inherited in future generations
Why can color-blindness manifest in males more than in females?
Males have two X chromosomes which increase the chance of inheriting the color-blindness allele.
What is the genetic composition of a female carrier for hemophilia?
XHXH
What is the possible blood type of an individual with the genotype IBi?
Blood type B
How does co-dominance differ from complete dominance in blood group inheritance?
Co-dominance results in intermediate traits, while complete dominance shows clear dominant-recessive relationships.
Why is DNA profiling more reliable than blood grouping in establishing paternity?
DNA profiling provides unique matches by comparing specific genetic markers from individuals.
What is the phenotypic ratio in the offspring of a dihybrid cross between TtPp x TtPp?
9:3:3:1
What genetic concept is exemplified by the expression of blood type O (ii) in individuals?
'Multiple Alleles'
How do males inherit color-blindness differently from females?
Males must inherit a single X chromosome carrying the color-blindness allele.
What is one potential benefit of genetic engineering in creating GMOs?
Improved pharmaceutical production
How is DNA profiling different from blood grouping in paternity testing?
DNA profiling compares DNA fragments, while blood grouping compares protein structures
What is a significant ethical concern associated with genetic engineering and cloning?
Embryonic stem cell research
How does paternity testing through DNA profiling provide a clearer indication of paternity?
By examining nucleotide sequences in DNA fragments
What distinguishes cloning from genetic engineering in terms of creating identical copies of organisms?
Cloning creates genetically identical copies, while genetic engineering introduces desired traits
What is one of the applications of cloning mentioned in the text?
Preserving endangered species
Why is it mentioned that DNA profiling is a more reliable method for paternity testing than blood grouping?
DNA profiling looks at nucleotide sequences, providing clearer results
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