CELL DIVISION
Page 1: CELL DIVISION
DIVIDE AND MULTIPLY
Covers pages 73-101.
Page 2: DIAGNOSTIC TESTS
Overview
Section not elaborated upon; context likely includes assessments related to cell division.
Page 3: GROWTH AND DEVELOPMENT
CELL REPLACEMENT
ASEXUAL REPRODUCTION
Definition: The production of offspring from a single parent without gametes.
Offspring are genetically identical to each other and to the parent.
Reasons for cell division:
Occurs when old cells die and new cells are formed.
Wound healing involves growth of new cells from cell division.
Organisms, including humans, develop from a single cell into trillions of cells due to numerous divisions.
Page 4: ASEXUAL REPRODUCTION IN BACTERIA - BINARY FISSION
Process of bacterial cell division:
DNA circular molecule makes a copy before division.
Cell reaches appropriate size and splits into two equal halves.
Cell constricts at the center, and eventually pinches apart, forming two daughter cells.
Page 5: ASEXUAL REPRODUCTION
Characteristics of Bacteria
Cell structure lacks a nucleus.
Less DNA consisting of a single circular chromosome and absence of spindle fibers.
Faster Reproduction Causes
Bacteria reproduce faster under favorable conditions.
Examples of Asexual Reproduction
Budding
Fragmentation
Vegetative Reproduction
Page 6: ASEXUAL REPRODUCTION (Repeated Information)
Same as Page 5: Cell structure without a nucleus, reproduction examples.
Page 7: ASEXUAL REPRODUCTION (Further Repetition)
Similar notes reiterating lack of nucleus and DNA structure attributes.
Page 8: VEGETATIVE PROPAGATION
Formation of a new plant from part of a parent plant.
Steps include:
Parent plant
Plant cutting
Soil and compost
New plant from planting.
Page 9: DNA AND CHROMOSOMES
DNA (Deoxyribonucleic Acid)
Definition: A double-stranded molecule carrying genetic information essential for normal body functions.
Chromosomes
Long continuous threads of DNA coiled with histone proteins.
Humans possess 46 chromosomes in body cells, approximately 10 feet long when fully extended.
Page 10: HUMAN CHROMOSOMES
Chromosomal information likely presented here but with incomplete data due to formatting issues.
Page 11: DNA STRUCTURE AND ORGANIZATION
Before and During Cell Division
DNA is loosely organized before division.
During cell division, DNA condenses into chromosomes to prevent entanglement, ensuring each daughter cell gets the correct genetic material.
Role of Histones
Proteins around which DNA wraps, facilitating DNA organization.
Page 12: CHROMATIN
Definition
A complex of loose DNA, proteins, and RNA responsible for packaging DNA efficiently within the nucleus.
Functions of Chromatin
Protects DNA structure and sequence.
Prevents DNA damage and controls gene expression and replication.
Condenses further during division into tight rods resembling X shapes after DNA replication.
Page 13: CHROMATID AND STRUCTURES
Key Terms
Chromatids: Each strand of duplicated chromosomes.
Sister chromatids: Two chromatids joined by a centromere.
Centromere: Pinched region of condensed chromosomes.
Kinetochore: Protein group at the centromere connecting spindle fibers during division.
Page 14: TELOMERES
Structures at the end of DNA strands protecting genetic material, preventing unintended attachment and gene loss.
Trivia: Telomeres shorten with each DNA replication to preserve gene integrity.
Page 15: TELOMERES (Reiteration)
Information regarding telomeres repeated, context similar to Page 14.
Page 16: MEDICAL MEDIA COPYRIGHT
No educational content included; likely a copyright notice regarding the materials used.
Page 17: CELL CYCLE STAGES
Overview
Definite stages are outlined:
Growth
DNA duplication
Cell division
Example: About 100 trillion cells in the body and implications of uncontrolled growth leading to abnormalities.
Page 18: STAGES OF CELL CYCLE
Main Processes
Interphase (G1, S, G2)
Mitosis
Cytokinesis.
Page 19: GAP 1 (G1)
Functions During G1
Cells perform metabolic functions and increase in size.
Rapid division in embryonic cells; cells spending most of their life cycle in this stage, influenced by size ratio of surface area to volume.
Page 20: INTERPHASE - G1 PHASE
Illustration or reference to centrioles during G1 phase.
Page 21: CHROMOSOMES
Likely a continued discussion of chromosomes within the G1 phase context.
Page 22: SYNTHESIS (S) PHASE
Key Concepts
Cell copies genetic material (nuclear DNA).
DNA replication ensures that daughter cells receive exact genetic copies.
Microtubules produced will assist in organizing cell contents for division.
Page 23: INTERPHASE - SYNTHESIS (S) PHASE
Chart or diagram denoting the synthesis phase with emphasis on DNA copying.
Page 24: GAP 2 (G2)
Functions During G2
Continued metabolic functions and further growth.
Critical checkpoint to ensure cell readiness for division: correct size and undamaged DNA.
Page 25: INTERPHASE - GAP 2 (G2) PHASE
References to centrioles during G2, possibly illustrating key processes completed by this phase.
Page 26: MITOSIS STAGES
Overview
Mitosis leads to the division of the nucleus and genetic material into daughter cells.
Four main stages:
Prophase
Metaphase
Anaphase
Telophase
Page 27: MITOSIS
Reiteration of mitosis phases; likely includes illustrations or detailed descriptions of each.
Page 28: CYTOKINESIS
Function
Division of cytoplasm, initiated during telophase and continuing post-nuclei formation.
Page 29: RATE OF CELL DIVISION
Variability
Varies among organisms and tissues based on necessity.
Faster during embryonic stages and childhood; higher rates in areas of wear and tear (e.g., skin).
Page 30: PERMANENTLY INACTIVE CELLS
Cell States
Some cells (neurons, heart cells) do not divide but perform functions; classified as permanently in G0 (Gap Zero).
Page 31: STAGES OF CELL CYCLE
Summary
Recap of the cell cycle stages emphasizing normal growth, DNA duplication, and cell division processes.