1.1 Flashcards
What does the abbreviation DNA stand for?
DNA stands for Deoxyribonucleic Acid.
What does the abbreviation RNA stand for?
RNA stands for Ribonucleic Acid.
Q: What are the three components of a nucleotide?
A: A nucleotide consists of a phosphate group, a five-carbon sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base (adenine, thymine, cytosine, guanine in DNA; uracil in RNA).
Q: Name the four nucleotides found in DNA.
A: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
Q: Name the four nucleotides found in RNA.
A: Adenine (A), Uracil (U), Cytosine (C), and Guanine (G).
Q: How do nucleotides link together to form polynucleotides?
A: Nucleotides are linked by phosphodiester bonds between the phosphate group of one nucleotide and the sugar of the next, creating a sugar-phosphate backbone.
Q: What is a gene, and where is it located?
A: A gene is a segment of DNA that contains instructions to make a specific protein. Genes are located on chromosomes within the cell nucleus.
Q: How many chromosomes do humans have, and how are they inherited?
A: Humans have 46 chromosomes, organized into 23 pairs. One chromosome from each pair is inherited from each parent, so offspring have half of their chromosomes from each parent.
Q: What is the difference between a gene and a chromosome?
A: A gene is a specific sequence of DNA that codes for a protein, while a chromosome is a long DNA molecule with many genes organized along its length.
Q: What is mitosis, and what is its main function?
A: Mitosis is a type of cell division that results in two genetically identical daughter cells. Its main function is for growth, repair, and asexual reproduction in multicellular organisms.
Q: What are the four main stages of mitosis?
A: The four main stages of mitosis are Prophase (chromosomes condense), Metaphase (chromosomes align), Anaphase (sister chromatids separate), and Telophase (chromosomes reach poles and the cell divides).
Q: How is meiosis different from mitosis?
A: Meiosis is a type of cell division that results in four genetically unique haploid cells, each with half the chromosome number of the parent cell. It is essential for sexual reproduction.
Q: What are the two main stages of meiosis, and what happens in each?
**A:
Meiosis I: Homologous chromosomes pair up and exchange genetic material (crossing over), then separate, resulting in two haploid cells.
Meiosis II: Sister chromatids separate, similar to mitosis, resulting in four haploid cells.**
Q: Explain how you can determine whether a cell observed in the middle of meiosis is undergoing Meiosis I or II.
A: During Meiosis I, homologous chromosomes pair up and may undergo crossing over, whereas in Meiosis II, sister chromatids are separating. Observing paired homologous chromosomes indicates Meiosis I, while separated sister chromatids indicate Meiosis II.
