B13-Reproduction Flashcards
What is asexual reproduction?
Asexual reproduction involves only one parent. The cells divide by mitosis, resulting in genetically identical offspring known as clones.
What is sexual reproduction?
Sexual reproduction involves two parents. Male and female gametes fuse to form a zygote, which develops into a new individual with genetic variation.
What is the genetic outcome of sexual reproduction?
Offspring with genetic variation, inheriting traits from both parents.
What are gametes?
Special sex cells (sperm and egg in animals, pollen and egg cells in plants) that fuse during sexual reproduction.
Why is variation important in sexual reproduction?
Variation is key to the long-term survival of a species as it allows for adaptation to changing environments.
What happens to the chromosome number during fertilization in humans?
The zygote has 46 chromosomes, the usual number, after the fusion of egg and sperm.
What is a zygote?
The cell formed by the fusion of two gametes during sexual reproduction.
What is meiosis?
Meiosis is a type of cell division that halves the number of chromosomes in gametes, resulting in four genetically different gametes.
Meiosis introduces variation by producing gametes with random mixtures of the original chromosomes, and each gamete is genetically different.
What are alleles?
Alleles are different forms of the same gene, which contribute to variation in the characteristics of offspring.
Advantages of asexual reporudcion
Time and energy efficient, only one parent
How do fungi typically reproduce?
Fungi typically reproduce asexually through spores produced by mitosis, but can reproduce sexually under adverse conditions to introduce variation.
How do plants reproduce sexually?
Plants reproduce sexually through flowers, where pollen (male gamete) fertilizes egg cells (female gamete), leading to seed formation and genetic variation.
How do plants reproduce asexually?
Plants can reproduce asexually through methods like runners (e.g., strawberries) or bulb division (e.g., daffodils), producing genetically identical offspring.
What is the role of DNA in inheritance?
DNA contains the genetic information that determines inherited characteristics, with genes coding for specific proteins that control cell functions.
What is the structure of DNA?
DNA is a double helix made up of nucleotides, each consisting of a sugar, a phosphate, and one of four bases (A, C, G, T).
What is a nucleotide?
A nucleotide is the basic unit of DNA, consisting of a sugar, a phosphate group, and one of four nitrogenous bases (A, C, G, T).
How does DNA control protein synthesis?
DNA sequences code for amino acids, which are assembled into proteins. The order of bases in DNA determines the order of amino acids, shaping the protein’s function.
What is the human genome?
The human genome is the complete set of genetic material in humans, including all chromosomes and mitochondrial DNA, containing over 3 billion base pairs and around 21,000 genes.
Why is understanding the human genome important?
It helps in understanding inherited disorders, predicting disease risks, developing treatments, and tracing human evolution and migration patterns
What is epigenetics?
Epigenetics is the study of how environmental factors and non-coding DNA influence gene expression and how genes interact with the environment.
How do mutations contribute to evolution?
Mutations introduce genetic variation, which can lead to new traits that may provide a survival advantage, driving natural selection and evolution.
What is the role of ribosomes in protein synthesis?
Ribosomes are the cellular structures where protein synthesis occurs, using the template provided by DNA to assemble amino acids into proteins.
What is the significance of the shape of a protein?
The shape of a protein determines its function, such as the active site of an enzyme, the structure of collagen, or the role of hormones and clotting factors.
What is the importance of the Human Genome Project?
The Human Genome Project has helped scientists understand inherited disorders, predict disease risks, develop treatments, and trace human evolution and migration patterns.
What is a gene?
A gene is a section of DNA that codes for a specific protein, influencing an organism’s characteristics.
What is an allele?
An allele is a different form of a gene, which can result in different traits or characteristics.
What is a homozygote?
A homozygote is an individual with two identical alleles for a particular gene (e.g., BB or bb).
What is a heterozygote?
A heterozygote is an individual with two different alleles for a particular gene (e.g., Bb).
What is genotype?
Genotype refers to the genetic makeup of an organism, specifically the alleles it possesses for a particular gene.
What is phenotype?
Phenotype refers to the physical appearance or characteristics of an organism, resulting from its genotype.
What is a dominant allele?
A dominant allele is one that is expressed in the phenotype even if only one copy is present (e.g., B for black coat in mice).
What is a recessive allele?
A recessive allele is only expressed in the phenotype if two copies are present (e.g., b for brown coat in mice).
What is a genetic cross?
A genetic cross is the breeding of two organisms to study the inheritance of specific traits in their offspring.
What is a Punnett square?
A Punnett square is a diagram used to predict the genotype and phenotype ratios of offspring from a genetic cross.
How are sex-linked traits inherited?
Sex-linked traits are inherited through genes located on the sex chromosomes, typically the X chromosome, and can show different patterns of inheritance in males and females.
What is the role of family trees in genetics?
Family trees help trace the inheritance of traits through generations, identifying patterns of dominant and recessive alleles.
What is the importance of studying genetics?
Studying genetics helps understand inheritance patterns, predict traits in offspring, and identify genetic disorders.
How is sex determined in humans?
Sex is determined by the combination of sex chromosomes inherited from the parents: XX for females and XY for males.
What is a codon?
A codon is a sequence of three bases in DNA that codes for a specific amino acid
What is polydactyly?
Polydactyly is a genetic disorder where individuals are born with extra fingers or toes, caused by a dominant allele. If one parent has the condition, there is a 50% chance of passing it to their offspring.
What is cystic fibrosis?
Cystic fibrosis is a genetic disorder that affects the lungs, digestive system, and reproductive system, caused by a recessive allele. Cystic fibrosis is inherited when both parents carry the recessive allele. There is a 25% chance their child will have the disorder.
What is a carrier in genetics?
A carrier is an individual who has one copy of a recessive allele for a genetic disorder but does not show symptoms.
What is Huntington’s disease?
Huntington’s disease is a dominant genetic disorder that affects the nervous system, with symptoms appearing in middle age.
What is amniocentesis?
Amniocentesis is a procedure carried out at around 15–16 weeks of pregnancy, involving the extraction of amniotic fluid containing fetal cells for genetic screening.
What is chorionic villus sampling?
Chorionic villus sampling is a procedure done between 10 and 12 weeks of pregnancy, involving the extraction of a small tissue sample from the developing placenta for genetic screening.
What are the risks associated with amniocentesis and chorionic villus sampling?
Both procedures carry a risk of causing a miscarriage.
What is pre-implantation genetic diagnosis (PGD)?
PGD is a method where embryos produced by IVF are tested for genetic disorders before implantation, ensuring only unaffected embryos are used.
What are the concerns about embryo screening?
Concerns include the risk of miscarriage, false positive or false negative results, ethical and emotional decision-making, economic costs, and the potential for “designer babies.”
What ethical considerations are involved in embryo screening?
Ethical considerations include the decision to terminate a pregnancy, personal and religious beliefs, and the potential for selecting desirable traits in offspring.
What are the economic considerations of embryo screening?
Screening is expensive, and there are costs associated with healthcare and support for children with genetic disorders.
What is the concern about “designer babies”?
The concern is that genetic screening could be used to select embryos with desirable traits, such as sex, appearance, or intelligence.
How are different alleles expressed?
Dominant-Expressed even when there is only one copy available
Recessive- Expressed when there are 2 alleles-homozygous trait
How does DNA control an organism?
Genes → proteins → specialized cells → tissues → organs → organ systems → whole body.
What is a genome?
The entire genetic material of an organism, including nuclear chromosomes and mitochondrial DNA.
Why are scientists sequencing non-human genomes?
To study evolutionary relationships, improve disease diagnosis (e.g., identifying pathogenic bacteria/viruses), and refine classification systems.
