B6 - Inheritance, Variation, and Evoloution Flashcards
What is mitosis and meiosis?
Mitosis is a type of cell division that results in two genetically identical daughter cells.
Meiosis is a type of cell division that results in four genetically different gametes with half the number of chromosomes.
What are sexual and asexual reproduction?
Sexual reproduction involves the fusion of male and female gametes, leading to genetic variation.
Asexual reproduction involves only one parent, producing genetically identical offspring (clones) through mitosis.
What is the function and process of meiosis?
Meiosis halves the number of chromosomes in gametes.
Steps: Copies of genetic information are made, the cell divides twice, forming four gametes with a single set of chromosomes, all genetically different.
What happens during fertilization?
Restores the full number of chromosomes.
What are DNA, genes, chromosomes, and the genome?
DNA is a polymer made of two strands forming a double helix.
Genes are small sections of DNA that code for proteins.
Chromosomes are structures containing DNA within the nucleus.
The genome is the entire genetic material of an organism.
Why is the Human Genome important?
Helps identify genes linked to diseases.
Aids in understanding and treating inherited disorders.
Can trace human migration patterns.
What are gametes and alleles?
Gametes are reproductive cells (sperm or egg in animals, pollen or egg in plants).
Alleles are different forms of a gene.
What are dominant and recessive alleles?
Dominant alleles are always expressed if present.
Recessive alleles are only expressed if two copies are present.
What do homozygous, heterozygous, genotype, and phenotype mean?
Homozygous: Two identical alleles for a trait.
Heterozygous: Two different alleles for a trait.
Genotype: The genetic makeup of an organism.
Phenotype: The physical expression of a genotype.
What are polydactyly and cystic fibrosis?
Polydactyly is caused by a dominant allele, leading to extra fingers or toes.
Cystic fibrosis is caused by a recessive allele, affecting cell membranes.
What is embryo screening and what are its ethical concerns?
A technique used to detect genetic disorders. Raises concerns about designer babies and ethical implications.
How is sex determined in humans?
Humans have 23 chromosome pairs.
Females: XX, Males: XY.
Genetic crosses predict the probability of sex inheritance.
What causes variation and mutations?
Variation is caused by genetic differences, environmental influences, or both.
Mutations are continuous changes in DNA. Most have no effect, but some can influence phenotype or provide an advantage.
What is evolution and natural selection?
Evolution is a change in inherited characteristics over time due to natural selection.
Natural selection: Variants with beneficial traits survive and reproduce, making these traits more common over time.
What is speciation?
When populations become so different that they can no longer interbreed, forming new species.
What is selective breeding and what are its risks?
Breeding organisms for desirable traits (e.g., disease resistance in crops, increased milk production in animals, dog temperament).
Risks: Reduces genetic diversity, increases risk of inherited diseases.
What is genetic engineering and how is it used?
Modifying the genome by introducing genes from another organism.
Examples: GM crops resistant to disease or pests, bacteria modified to produce human insulin.
What are concerns about genetic engineering?
Effects on ecosystems, unknown health impacts of GM food.
What is the process of genetic engineering?
Isolate the desired gene using enzymes.
Insert the gene into a vector (bacterial plasmid or virus).
Transfer the gene into target cells.
Modify cells early in development to ensure the desired traits.
What is the fossil record and what does it show?
Shows how species have changed over time.
Many early life forms were soft-bodied, leaving few fossils. Some fossil evidence has been lost due to geological activity.
How does antibiotic resistance in bacteria support evolution?
Bacteria reproduce quickly, leading to rapid evolution.
Mutations create antibiotic-resistant strains, making infections harder to treat.
Example: MRSA.
How can antibiotic resistance be prevented?
Avoid overusing antibiotics.
Complete prescribed antibiotic courses.
Reduce antibiotic use in agriculture.
What is the Linnaean system and binomial nomenclature?
Kingdom, Phylum, Class, Order, Family, Genus, Species.
Uses binomial nomenclature (Genus species).
What is the Three-Domain System (Carl Woese)?
Archaea: Primitive bacteria found in extreme environments.
Bacteria: True bacteria.
Eukaryota: Includes protists, fungi, plants, and animals.
What are evolutionary trees and what do they show?
Show relationships between organisms based on fossil and genetic data.
