Genetics

• Chromosomes are made up of genes that contain instructions for making proteins.
• The nucleus is surrounded by a double membrane called the nuclear envelope.
• DNA is found inside chromosomes and contains genetic information passed down from parents to offspring.
• Meiosis is important because it allows genetic variation through sexual reproduction
• What is the difference between meiosis and mitosis?


  Mitosis is used in normal cell division and meiosis is only used in sex cell division during sexual reproductions
• Why was the Human Genome Project important?


  Genetic research so that we can develop new medicines for genetic diseases
• Double helix


  The twisted, spiral structure of DNA, formed by hydrogen bonding between complementary base pairs
• Base pairing rules


  A pairs with T, and G pairs with C
• Hydrogen bonding


  The weak chemical bonds between the nitrogenous bases, holding the double helix together
• Chromosomal mutations


  Changes in the DNA sequence or number of chromosomes
• Why is sexual reproduction beneficial for a species?

  It provides genetic variation, allowing organisms to adapt to environmental changes
• What is a major drawback of sexual reproduction in endangered species?

  Finding a mate can be difficult when few individuals are left
• What is a key advantage of asexual reproduction?

  Asexual reproduction is fast and allows for quick population replenishment
• What type of cell division creates gametes?

  Meiosis
• What is a disadvantage of asexual reproduction regarding disease susceptibility?

  Genetically identical organisms can be more susceptible to diseases
• How many cells does meiosis produce, and how are they different?

  Meiosis produces four genetically different haploid cells
• What must happen before meiosis begins?

  DNA replication must occur
• How do chromosomes count in meiosis after replication?

  They are counted by the centromere, so one duplicated chromosome counts as one
• What happens during the first division of meiosis?

  The chromosomes move to each end of the cell
• What does DNA stand for?

  Deoxyribonucleic acid
• What is the result of the second division in meiosis?

  The chromatids move away to each end of the cell
• What is the shape of DNA?

  DNA has a double helix shape
• What are the components of a nucleotide?

  A nucleotide is made up of a phosphate, a sugar (deoxyribose), and a base
• How many types of bases are there in DNA, and what are they?

  There are four types of bases: A, T, C, and G
• How do the bases pair in DNA?

  A pairs with T, and C pairs with G
• What is the process of making proteins called?

  The process is called protein synthesis
• What is the significance of the order of bases in DNA?

  The order of bases is unique to each individual and codes for protein synthesis
• What are the two parts of protein synthesis?

  The two parts are transcription and translation
• Where does transcription occur?

  Transcription occurs in the nucleus
• What molecule bonds to DNA during transcription?

  mRNA bonds to DNA
• How does mRNA differ from DNA in terms of base pairing?

  mRNA uses U instead of T, so A pairs with U
• What happens during translation?

  tRNA reads mRNA codons and brings amino acids to form a protein
• What happens to mRNA after transcription?

  mRNA travels out of the nucleus to find a ribosome
• What is a gene?

  A gene is a section of DNA that codes for a specific characteristic
• What is an allele?

  An allele is a different version of a gene
• What does homozygous mean?

  Homozygous means having two identical alleles for a gene
• How many alleles does a person have for each gene?

  A person has two alleles for each gene, one from each parent
• What does heterozygous mean?

  Heterozygous means having two different alleles for a gene
• How are dominant and recessive alleles represented?

  Dominant alleles are represented by capital letters, and recessive alleles by lowercase letters
• What happens if a person has one dominant allele and one recessive allele?

  The dominant allele will overpower the recessive allele, showing the dominant trait