Compendium 12

Cytokinesis is the process of dividing the cytoplasm to form two distinct daughter cells, which begins during anaphase and continues through telophase.

Centrioles are involved in organizing microtubules during mitosis, helping to form the mitotic spindle that separates chromosomes.

Chromatin is the loose, uncondensed form of DNA found during interphase, which condenses into chromosomes during mitosis.

<p>Skin cells undergo constant mitosis to regenerate from the basal layer, facilitating repair and replacement in response to abrasion or injury.</p> Signup and view all the answers

<p>Mitosis involves prophase (chromosomes condense), metaphase (chromosomes align), anaphase (chromatids separate), and telophase (nuclei reform).</p> Signup and view all the answers

<p>Crossing over during meiosis enhances genetic diversity by allowing homologous chromosomes to exchange DNA segments.</p> Signup and view all the answers

<p>Meiosis produces four genetically different haploid gametes, while mitosis produces two genetically identical diploid daughter cells.</p> Signup and view all the answers

<p>During telophase 2, new nuclei form around the separated chromosomes, resulting in the completion of meiosis.</p> Signup and view all the answers

<p>The four phases of mitosis are prophase, metaphase, anaphase, and telophase. For example, during prophase, chromatin condenses into chromosomes and the nuclear membrane begins to break down.</p> Signup and view all the answers

<p>Centrioles help in organizing the mitotic spindle which separates the chromatids during anaphase.</p> Signup and view all the answers

<p>Cytokinesis is the division of the cytoplasm of a cell, resulting in the formation of two daughter cells. It is significant because it completes the cell division process after mitosis.</p> Signup and view all the answers

<p>Chromatin is a relaxed form of DNA that is complexed with proteins, while chromosomes are tightly coiled structures formed during cell division that consist of two sister chromatids.</p> Signup and view all the answers

<p>Mitosis allows for the production of two identical daughter cells, facilitating the replacement of damaged or dead cells during tissue regeneration.</p> Signup and view all the answers

<p>A karyotype is a map of an individual's chromosomes, obtained by staining and photographing cells during metaphase.</p> Signup and view all the answers

<p>Homologous chromosomes are pairs of chromosomes, one inherited from each parent, that contain the same genes at the same loci. They are important for genetic diversity and proper meiosis.</p> Signup and view all the answers

<p>During DNA replication, chromatin unwinds and each strand is replicated, resulting in two identical strands of DNA for each chromosome.</p> Signup and view all the answers

<p>An allele is a different form of the same gene found at a specific locus on homologous chromosomes. They are relevant because they contribute to genetic variation in traits.</p> Signup and view all the answers

<p>Having 23 pairs of chromosomes ensures that humans possess a diploid number of 46, which maintains genomic stability and enables sexual reproduction.</p> Signup and view all the answers

<p>Chromatin condenses to form chromosomes.</p> Signup and view all the answers

<p>Centrioles migrate to opposite ends of the cell and organize spindle fibers.</p> Signup and view all the answers

<p>Cytokinesis is the division of the cytoplasm, resulting in two daughter cells.</p> Signup and view all the answers

<p>Each chromosome consists of two chromatids joined at the centromere.</p> Signup and view all the answers

<p>Chromosomes are aligned at the nuclear equator, ensuring equal separation.</p> Signup and view all the answers

<p>In anaphase, the chromatids separate and are referred to as chromosomes.</p> Signup and view all the answers

<p>The completion of telophase marks this transition.</p> Signup and view all the answers

<p>DNA replication ensures that each daughter cell receives a complete set of chromosomes.</p> Signup and view all the answers

<p>Chromatin is a less condensed form of DNA, while chromosomes are tightly packed for cell division.</p> Signup and view all the answers

<p>Mitosis allows for the replacement of damaged or dead cells, facilitating tissue regeneration.</p> Signup and view all the answers

<p>It leads to an exchange of genetic material between homologous chromosomes, creating new gene combinations and genetic variation.</p> Signup and view all the answers

<p>Spermatogenesis produces four functional sperm cells in each division, while oogenesis yields one functional oocyte and three polar bodies.</p> Signup and view all the answers

<p>DNA has two strands and contains deoxyribose and thymine, whereas RNA is single-stranded, contains ribose, and has uracil instead of thymine.</p> Signup and view all the answers

<p>This occurs during prophase 1.</p> Signup and view all the answers

<p>mRNA is synthesized in the nucleus during transcription and carries the genetic code from DNA to the ribosomes for protein production.</p> Signup and view all the answers

<p>The phases of mitosis are prophase, metaphase, anaphase, and telophase. Their primary purpose is to ensure the accurate division of the cell's duplicated genetic material into two daughter cells.</p> Signup and view all the answers

<p>Centrioles organize the mitotic spindle, which is essential for separating chromosomes during cell division. They facilitate the proper alignment and movement of chromosomes to ensure accurate distribution to daughter cells.</p> Signup and view all the answers

<p>Cytokinesis is the final stage of cell division where the cytoplasm divides, forming two separate daughter cells. It is important because it ensures that each daughter cell has its own organelles and sufficient cytoplasm to function properly.</p> Signup and view all the answers

<p>Chromatin is a relaxed form of DNA, allowing for gene expression during interphase, while chromosomes are tightly coiled structures that are visible during mitosis when the DNA condenses. This compaction is necessary for accurate segregation during cell division.</p> Signup and view all the answers

<p>Mitosis allows for the proliferation of somatic cells, which is crucial for replacing damaged or lost cells in tissues. This regenerative process is essential for growth, healing, and maintenance of multicellular organisms.</p> Signup and view all the answers

<p>The diploid number of chromosomes in somatic cells (46) ensures that each daughter cell receives a complete set of genetic information after cell division. This is critical for maintaining genetic stability across generations.</p> Signup and view all the answers

<p>Meiosis results in four genetically diverse haploid gametes, while mitosis produces two genetically identical diploid daughter cells. Meiosis includes two rounds of division and promotes genetic diversity through recombination.</p> Signup and view all the answers

<p>Interphase is the longest phase of the cell cycle, during which the cell grows, replicates its DNA, and prepares for mitosis. It is critical for ensuring the cell is fully ready for division.</p> Signup and view all the answers

<p>Errors during mitosis can lead to aneuploidy, where daughter cells have an abnormal number of chromosomes, potentially causing diseases such as cancer. Genetic instability can arise from such errors, influencing cell function and proliferation.</p> Signup and view all the answers

<p>Post-translational modifications, such as phosphorylation or glycosylation, can change a protein's activity, localization, or stability, thereby regulating its function and involvement in cellular processes. These modifications are critical for activating or inactivating proteins as needed.</p> Signup and view all the answers

<p>Meiosis produces four non-identical gamete cells, each having a haploid number of chromosomes, resulting in genetic variation.</p> Signup and view all the answers

<p>Homologous crossing over occurs during Prophase I, and it creates new gene combinations which enhance genetic diversity.</p> Signup and view all the answers

<p>Spermatogenesis produces four functional sperm cells per division, while oogenesis results in one functional oocyte and three polar bodies.</p> Signup and view all the answers

<p>DNA consists of two strands forming a double helix and contains deoxyribose and thymine, while RNA is a single strand made of ribose and uracil.</p> Signup and view all the answers

<p>mRNA carries the genetic code from DNA in the nucleus to ribosomes for protein synthesis.</p> Signup and view all the answers

<p>Globular proteins play critical roles in nearly all biological processes and are more functional due to their compact, water-soluble structures.</p> Signup and view all the answers

<p>The proteome differs due to the expression of different genes, which leads to the production of distinct proteins specific to each cell type.</p> Signup and view all the answers

<p>The two main steps of gene expression are transcription, which occurs in the nucleus, and translation, which takes place in the cytoplasm.</p> Signup and view all the answers

<p>Transcription factors recruit the enzyme RNA polymerase to initiate the polymerization of messenger RNA from the DNA template.</p> Signup and view all the answers

<p>The central dogma describes the flow of genetic information from DNA to RNA to protein, highlighting how genes direct the synthesis of proteins.</p> Signup and view all the answers

<p>The specific arrangement of amino acids in a polypeptide chain determines the protein's shape, properties, and functions.</p> Signup and view all the answers

<p>mRNA serves as the template that carries the genetic code from DNA to ribosomes, where it is translated into a protein.</p> Signup and view all the answers

<p>Examples of globular proteins include haemoglobin, myoglobin, insulin, and most enzymes.</p> Signup and view all the answers

<p>Cellular DNA contains the genetic information needed to produce proteins by defining the sequences that determine amino acid arrangement.</p> Signup and view all the answers

<p>The coding strand contains the gene sequence and is identical to the mRNA, while the template strand is used to produce the complementary RNA.</p> Signup and view all the answers

<p>Keratin provides strength to skin, hair, and nails.</p> Signup and view all the answers

<p>Proteins yield as much energy as carbohydrates per unit of weight.</p> Signup and view all the answers

<p>The two main types are alpha helices and beta pleated sheets.</p> Signup and view all the answers

<p>The tertiary structure is determined by the 3D folding of the secondary structures.</p> Signup and view all the answers

<p>Fibrous proteins are elongated and provide structural support, while globular proteins are more compact and functional.</p> Signup and view all the answers

<p>The quaternary structure is the combined 3D structure of two or more polypeptide chains, such as haemoglobin.</p> Signup and view all the answers

<p>The recommended protein intake is 10-35% of total calorie consumption.</p> Signup and view all the answers

<p>Protein receptors facilitate cell-to-cell communication by transmitting signals across the cell membrane.</p> Signup and view all the answers

<p>Proteins are made up of amino acids linked by peptide bonds.</p> Signup and view all the answers

<p>Side chains affect how a protein folds and its final shape.</p> Signup and view all the answers

<p>During prophase, chromatin condenses into chromosomes and centrioles migrate to opposite ends of the cell.</p> Signup and view all the answers

<p>In metaphase, chromosomes align at the nuclear equator, attaching to the spindle fibres.</p> Signup and view all the answers

<p>During anaphase, spindle fibres separate the chromatids, resulting in two identical sets of chromosomes moving towards opposite ends.</p> Signup and view all the answers

<p>In telophase, the nuclear envelope reforms around each set of chromosomes as they decondense back into chromatin.</p> Signup and view all the answers

<p>Spindle fibres attach to the centromeres of chromosomes and help in their alignment and separation during cell division.</p> Signup and view all the answers

<p>Centrioles organize the formation of spindle fibres and move to opposite ends of the cell before cell division.</p> Signup and view all the answers

<p>Cytokinesis involves the division of the cytoplasm, resulting in two separate daughter cells.</p> Signup and view all the answers

<p>The 'S' phase is crucial for DNA replication, ensuring that each daughter cell receives a complete set of chromosomes.</p> Signup and view all the answers

<p>Chromatin condenses into visible chromosomes during prophase and decondenses back into chromatin during telophase.</p> Signup and view all the answers

<p>The mnemonic 'I Pay My Annual Taxes' helps remember the stages: Interphase, Prophase, Metaphase, Anaphase, Telophase.</p> Signup and view all the answers

<p>DNA is double-stranded with deoxyribose sugar, whereas RNA is single-stranded with ribose sugar. DNA stores genetic information, while RNA is involved in protein synthesis.</p> Signup and view all the answers

<p>A nucleotide consists of a pentose sugar, a phosphate group, and a nitrogenous base. These components link together to form polynucleotide chains, which make up DNA and RNA.</p> Signup and view all the answers

<p>Homologous chromosomes are pairs of chromosomes, one from each parent, that contain genes for the same traits. They are essential for genetic diversity and proper segregation during meiosis.</p> Signup and view all the answers

<p>A karyotype is a map of the chromosomes in a dividing cell, displaying their number and structure. It can reveal chromosomal abnormalities or genetic disorders.</p> Signup and view all the answers

<p>mRNA carries genetic information from DNA to the ribosome, tRNA brings amino acids to the ribosome, and rRNA is a structural component of ribosomes. Together, they facilitate translation.</p> Signup and view all the answers

<p>Non-coding DNA comprises 98.5% of DNA and includes regulatory sequences and introns, which do not code for proteins. It plays crucial roles in gene regulation and genome structure.</p> Signup and view all the answers

<p>Essential amino acids must be consumed through diet, non-essential amino acids can be synthesized in the body, and conditional amino acids are usually not essential but needed during illness or stress.</p> Signup and view all the answers

<p>Dominant alleles express their traits even in a single dose, while recessive alleles require two doses for expression. For instance, in pea plants, a dominant allele for tallness (T) masks a recessive allele for shortness (t).</p> Signup and view all the answers