B6: Inheritance, variation & evolution

• What type of reproduction involves the fusion of gametes?

  Sexual
• Sexual reproduction leads to variation because chromosomes exchange genetic material during meiosis.
• Asexual reproduction produces genetically identical offspring.
• What is the advantage of asexual reproduction in plants?

  Only one parent needed
• The term for all the genetic material in an organism is the genome.
• A gene is a section of DNA that codes for a specific protein.
• When was the initial goal of the Human Genome Project completed?

  2003
• Genotype refers to the genetic code stored in DNA, while phenotype refers to how that code is expressed in traits.
• What is the advantage of asexual reproduction for a plant in isolation?

  Only one parent needed
• The parasite that causes malaria can reproduce both sexually and asexually.
• The term for all the genetic material in an organism is its genome
• What shape is DNA?

  Double helix
• A gene is a section of DNA that codes for a specific protein.
• The Human Genome Project completed its initial goal in 2003
• What is the purpose of mapping the human genome?

  Identify disease-causing genes
• Phenotype refers to how the genetic code is expressed in an organism's characteristics
• Match the DNA base with its complementary pair:

  A ↔️ T

  C ↔️ G
• Steps in protein synthesis

  1️⃣ DNA sequence is copied by mRNA

  2️⃣ mRNA exits the nucleus

  3️⃣ mRNA binds to a ribosome

  4️⃣ Amino acids are linked to form a protein
• What role does a ribosome play in protein synthesis?

  Links amino acids
• Harmful mutations can result in a protein that does not perform its function
• What is epigenetics?

  Study of gene expression
• Some DNA does not directly code for proteins but influences gene expression.
• What is the term for different types of the same gene?

  Allel
• A dominant allele results in a characteristic being expressed even if another allele is present
• A recessive allele is expressed only when no dominant allele is present.
• What is the genotype of an individual with blue eyes if brown eyes are dominant?

  bb
• An organism with two identical alleles is called homozygous
• What is the purpose of a Punnett square?

  Predict phenotype probability
• Two heterozygous parents for eye color have a 25% chance of producing a child with blue eyes if blue eyes are recessive.
• Polydactyly, which results in extra fingers or toes, is caused by a dominant allele
• What type of allele causes cystic fibrosis?

  Recessive
• Two parents without cystic fibrosis can have a child with the disorder if both carry the recessive allele.
• Which pair of chromosomes determines sex in humans?

  XX or XY
• The XX chromosome combination results in a female
• The expression of sex chromosomes affects every cell in the body.
• What are the two main causes of variation in offspring?

  Genes and environment
• Charles Darwin's theory of evolution states that random variation results in some organisms being better suited to their environment
• DNA can respond to environmental changes by turning genes on or off.
• What happened to blind mackerel bred in sunlight?

  Regained eyes and skin
• John-Baptiste Lamarck's theory of adaptation was later partially supported by discoveries in epigenetics