Chapter 3 dna and protein sysnthesis tuesday 9/30

Movement from chemistry to cell functionality.
Importance of the material discussed:
- Discussed in virtually every biology class.
- Central to understanding biology, DNA, and proteins.

Cells live in a cycle rather than a linear born-live-die narrative.
Concept of cellular rebirth:
- Each cell is a combination of old and new ("reborn").
- Importance of understanding this cyclic nature of cells.
Mitosis Cycle Breakdown:
- Prophase: initial stage where chromosomes condense and become visible.
- Metaphase: chromosomes line up at the cell equator.
- Anaphase: sister chromatids are pulled apart.
- Telophase: chromosomes de-condense, forming two nuclei.
- Cytokinesis: division of the cytoplasm to form two new cells.

Interphase phases:
- G1 (Growth 1): Growth and normal cellular functions.
  - Example:
    - Liver cells detoxifying blood.
    - Kidney cells removing metabolic waste.
    - Muscle cells performing contraction functions.
- S (Synthesis): DNA replication occurs here.
- G2 (Growth 2): Prepares for mitosis; further growth occurs.
G1 Checkpoint:
- Pauses cellular processes until conditions are right for division.
- Crucial for cancer cell understanding; cancer cells bypass checkpoints leading to uncontrolled division.

DNA as the central topic of study in this guide.
DNA is organized in a double helix:
- Structure changes between interphase (thin and accessible) and mitotic phase (coiled and condensed).
Nucleotides: Basic unit of DNA. Each is composed of:
- Phosphate group
- Sugar (ribose in RNA, deoxyribose in DNA)
- Nitrogenous base (the unique part that varies between nucleotides)
  - Four main bases: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).
Complementary base pairing:
- A always pairs with T; C always pairs with G.
  - Importance of hydrogen bonds holding base pairs together.
Antiparallel nature of DNA:
- One strand runs 5' to 3', the other 3' to 5'.
  - Designations convey directionality of DNA strands based on carbon numbering in ribose sugar.
Sugar-phosphate backbone:
- Covalent bonds between sugars and phosphates forming the vertices of the double helix.

Roles of DNA in cellular function:
- Directs cellular activities through protein synthesis.
Importance of DNA integrity for cell survival and function:
- DNA instructions must be protected from environmental chaos.
- The necessity for a copy of DNA (RNA) to be accessible for everyday cellular functions.

Process begins at the promoter area of a gene in DNA.
RNA Polymerase: An enzyme that helps synthesize RNA by copying a DNA template:
- Functions include opening up DNA, reading template, and creating RNA strand.
RNA production follows complementary base pairing rules.
- RNA strand is synthesized in a 5' to 3' direction, using DNA as a template.
Transcription ends when RNA Polymerase reaches a termination sequence.

S phase correlates with DNA replication while protein synthesis can occur throughout the cell life cycle.
Highlight the distinctions between DNA replication and protein synthesis:
- DNA replication: Copying of entire genomic information, occurs during S phase (specific).
- Protein synthesis: Constantly occurring as needed for cellular function.
Understanding DNA and protein synthesis is crucial for grasping cell biology.

The relationship between cell division, DNA replication, and protein synthesis is fundamental in understanding cellular function and life processes.
Importance of monitoring health and integrity of the DNA with implications for diseases such as cancer.
Proteins built from DNA instructions are critical in carrying out cellular tasks and overall organism function.