Cell Cycle

<p>Chromosomes</p> Signup and view all the answers

<p>Histone proteins</p> Signup and view all the answers

<p>It is constant within species</p> Signup and view all the answers

<p>6</p> Signup and view all the answers

<p>4</p> Signup and view all the answers

<p>Independent assortment of chromosomes</p> Signup and view all the answers

<p>Possession of favourable alleles or allele combinations</p> Signup and view all the answers

<p>A change in population allele frequency over time</p> Signup and view all the answers

<p>Crossing over</p> Signup and view all the answers

<p>S phase</p> Signup and view all the answers

<p>It holds together sister chromatids</p> Signup and view all the answers

<p>M phase</p> Signup and view all the answers

<p>They have sister chromatids</p> Signup and view all the answers

<p>G2 phase</p> Signup and view all the answers

<p>Epithelial cells</p> Signup and view all the answers

<p>Random division of chromosomes and a large number of possible chromosome combinations</p> Signup and view all the answers

<p>Genetic recombination and differences in gametes produced after Meiosis II</p> Signup and view all the answers

<p>Formation of four haploid cells</p> Signup and view all the answers

<p>They sort independently during meiosis</p> Signup and view all the answers

<p>Random assortment and independent assortment of chromosomes</p> Signup and view all the answers

<p>It varies between species</p> Signup and view all the answers

<p>Ensures correct attachment of sister chromatids to spindle fibers</p> Signup and view all the answers

<p>Apoptosis is triggered</p> Signup and view all the answers

<p>Asexual reproduction leads to genetically identical offspring, while sexual reproduction involves genetic variation</p> Signup and view all the answers

<p>Diploid organisms have two sets of chromosomes, while haploid organisms have one set</p> Signup and view all the answers

<p>Homologous chromosomes have the same genes at the same loci, with alleles as alternative gene versions</p> Signup and view all the answers

<p>Meiosis</p> Signup and view all the answers

<p>Chromosomes are composed of chromatin (DNA-protein complex) and appear as condensed threadlike structures during mitosis.</p> Signup and view all the answers

<p>Genome refers to the total hereditary endowment of DNA and is significant as it carries the genomic information from cell to cell, maintaining genetic traits within a species.</p> Signup and view all the answers

<p>The two definitions of a gene are the 'one gene-one protein' definition and the 'one gene-one polypeptide' definition. They differ in terms of specifying the primary structure of a protein by indicating that a gene is a sequence of DNA/nucleotides/codons that specifies the primary structure of a protein (or a polypeptide), and also sections of DNA that code for a useful product, such as protein/polypeptide, tRNA, rRNA, or other forms of RNA.</p> Signup and view all the answers

<p>Independent assortment of chromosomes during Meiosis I results in a random division of chromosomes, leading to a large number of possible chromosome combinations. This random assortment results in different genetic information in offspring, making each unique.</p> Signup and view all the answers

<p>Crossing over during Meiosis I involves the exchange of genetic material between homologous chromosomes, leading to genetic recombination. This process contributes to the differences in gametes produced after Meiosis II.</p> Signup and view all the answers

<p>Genes on the same chromosome may be linked, with the probability of segregation being dependent on the degree of genetic linkage. This linkage affects the independent assortment of genes during meiosis.</p> Signup and view all the answers

<p>Cell cycle checkpoints play a crucial role in ensuring accurate DNA duplication and equal chromosome distribution to daughter cells. Examples of specific checkpoints include the M checkpoint, which ensures correct attachment of sister chromatids to spindle fibers, and the G1 checkpoint, which assesses the integrity of DNA and proper chromosome duplication. These checkpoints stop the cell cycle if there's a problem and trigger apoptosis if the problem can't be fixed, thus preventing the propagation of mutated cells.</p> Signup and view all the answers

<p>Meiotic cell division is significant in generating genetic variation as it involves the formation of haploid gametes with unique combinations of genetic material through processes such as independent assortment and crossing over. In contrast, asexual reproduction through mitotic cell division leads to genetically identical offspring, while sexual reproduction involves meiotic cell division, gamete formation, and genetic variation due to the combination of genetic material from two parents.</p> Signup and view all the answers

<p>Diploid organisms have two sets of chromosomes, while haploid organisms have one set. This difference in ploidy levels has implications for genetic diversity and inheritance, as diploid organisms possess homologous chromosomes with potential for genetic recombination and diversity through processes such as crossing over during meiosis, while haploid organisms have limited genetic variation due to the absence of homologous chromosomes.</p> Signup and view all the answers

<p>The centromere is a specialized zone of DNA where sister chromatids are held together, and kinetochores are produced during the M phase. The attachment of kinetochores to spindle fibers ensures proper chromosome segregation and genetic stability.</p> Signup and view all the answers

<p>The G0 phase is a resting phase in the cell cycle. Some cell types, such as neurons, some liver cells, and some kidney cells, may permanently enter this phase. The G0 phase is significant as it allows cells to temporarily or permanently cease division, contributing to cellular diversity and specialized functions within an organism.</p> Signup and view all the answers

<p>Cell cycle mis-regulation is associated with cancer, highlighting the importance of understanding cell cycle regulation and checkpoints. Research in the field focuses on assessing the integrity of DNA, proper chromosome duplication, and attachment of kinetochores to spindle fibers at the G1, G2, and M checkpoints, respectively, to develop targeted cancer therapies and treatments.</p> Signup and view all the answers

<p>The three sexual sources of genetic variation are independent assortment of chromosomes, crossing over, and random fertilization. These sources contribute to evolution by creating new allele combinations, some of which may be more favorable in a given environment. Individuals possessing these favorable alleles have a higher probability of survival and reproduction, leading to an increase in their frequency in the population over time (micro-evolution).</p> Signup and view all the answers

<p>The estimated ~6 crossovers per homologous pair in Baker’s yeast during meiosis contribute to genetic variation by creating new combinations of alleles. This increases the likelihood of producing unique gametes with different allele combinations, ultimately leading to increased genetic diversity within the population.</p> Signup and view all the answers

<p>Sexual reproduction reshuffles genetic combinations through processes such as independent assortment of chromosomes, crossing over, and random fertilization. This reshuffling generates new allele combinations, some of which may be more favorable in specific environments. Individuals carrying these favorable allele combinations have a higher probability of survival and reproduction, potentially leading to adaptation and increased frequency of these alleles in the population over time (micro-evolution).</p> Signup and view all the answers