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Questions and Answers
What is the main purpose of the S Phase in the cell cycle?
During which phase does the nuclear envelope start to dissociate?
What happens to sister chromatids during Prophase?
Which organelles disperse toward the periphery of the cell during Prophase?
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What is the first step in karyokinesis?
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Which phase involves physical separation of cytoplasmic components into two daughter cells?
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What is the role of centrosomes in Prophase?
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Study Notes
Locus and Genes
- The position of genes on chromosomes is referred to as the locus (plural: loci).
Function of DNA
- Stores all genetic information needed for an organism to grow, develop, reproduce, control cell function, and survive.
- Determines the characteristics of an organism.
- Carries and transmits genetic instructions from parents to offspring.
DNA Replication
- The process by which DNA makes a copy of itself during cell division.
- Semiconservative, meaning each strand in the DNA double helix acts as a template for the synthesis of a new, complementary strand.
- Involves three stages:
- Stage one: The DNA helix structure is unwound and unzipped.
- Stage two: The two separated strands act as templates for making new strands of DNA.
- Stage three: The two new strands twist to form a double helix, identical to the original strand.
- Involves enzymes, including DNA polymerase.
Replication Fork
- A structure formed within the long helical DNA during DNA replication.
- Formed due to unwinding and separation of the two strands, appearing like a Y-shaped fork.
Leading and Lagging Strands
- Leading strand: The new DNA strand synthesized in the same direction as the growing replication fork.
- Lagging strand: The new DNA strand synthesized in the opposite direction to the growing replication fork.
RNA Structure and Function
- Single-stranded structure containing the sugar ribose, phosphates, and the nitrogenous bases A, G, C, and U (replacing T).
- Three main types: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).
- Functions in protein synthesis and genetic information storage in some viruses.
- Facilitates translation of DNA into proteins required by organisms.
Cell Division
- Enables growth and reproduction of organisms.
- The S Phase (Synthesis of DNA) is a stage in which DNA replication proceeds to form identical pairs of DNA molecules (sister chromatids).
- The G2 Phase (Second Gap) is a stage in which the cell replenishes its energy stores and prepares for mitosis.
Mitosis
- The division of somatic cells (skin, muscles, lungs, gut, hair, etc.).
- Has two phases: karyokinesis (nuclear division) and cytokinesis (physical separation of cytoplasmic components into two daughter cells).
- Karyokinesis divided into four stages: prophase, metaphase, anaphase, and telophase.
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Description
Test your knowledge on genetics, DNA function, and human karyotype with this quiz. Explore topics such as locus, genetic information storage, and hereditary material transmission.
