Genetics AP Unit

Cell Cycle

Series of phases for cell division and replication.

Cyclins

Proteins that fluctuate in levels during the cell cycle.

Cyclin-dependent Kinases (CDK)

Enzymes activated by cyclins to regulate the cell cycle.

Maturation-Promoting Factor (MPF)

Complex that initiates mitosis and chromosome condensation.

Checkpoints

Control points assessing readiness to progress in the cycle.

G1 Checkpoint

Critical checkpoint determining if a cell can divide.

G0 Phase

Resting state for cells not receiving division signals.

Internal Signals

Signals from within the cell affecting cycle progression.

External Signals

Growth factors and nutrients influencing cell division.

Platelet-derived Growth Factor (PDGF)

Stimulates fibroblast division as an external signal.

Cancer Cells

Exhibit uncontrolled growth and ignore regulatory mechanisms.

Density-dependent Inhibition

Normal cells stop dividing when crowded.

Anchorage Dependence

Cells require attachment to divide; cancer cells ignore this.

Tumours

Abnormal growths that can be benign or malignant.

Transformation

Genetic changes converting normal cells into cancer cells.

Chemotherapy

Treatment disrupting specific cell cycle steps to halt division.

High-energy Radiation

Damages DNA in localized tumours for treatment.

Microtubule Depolymerization

Interferes with mitosis during chemotherapy treatment.

Evolution of Mitosis

Hypothesis involving intermediate stages in unicellular protists.

Diatoms

Protists where nuclear envelope remains intact during division.

Dinoflagellates

Protists with chromosomes attached to nuclear envelope during division.

Cell Cycle Control System

Cyclically operating molecules coordinating cell cycle events.

Kinetochores

Protein structures that ensure proper chromosome alignment.

Diatoms

Organisms with unique spindle structure during mitosis.

Mitosis

Process of cell division resulting in two identical cells.

Cell Cycle

Series of phases cells undergo for division.

Cytoplasmic Signals

Factors driving cell cycle progression via cytoplasm.

G1 Checkpoint

Critical control point determining cell cycle progression.

Go Phase

Nondividing state for cells not receiving signals.

Cyclins

Proteins regulating cell cycle by activating Cdks.

Cyclin-Dependent Kinases (Cdks)

Enzymes activated by cyclins to regulate cell cycle.

MPF (M-phase-promoting factor)

Cyclin-Cdk complex essential for mitosis initiation.

Checkpoints

Control points in cell cycle for progression regulation.

Human Skin Cells

Cells that divide frequently due to high turnover.

Liver Cells

Cells that divide only during specific conditions.

S Phase

Phase where DNA synthesis occurs in the cell cycle.

M Phase

Phase where mitosis and cytokinesis occur.

Anaphase

Stage in mitosis where sister chromatids separate.

Kinetochores

Protein structures on chromosomes for spindle attachment.

Nuclear Envelope Breakdown

Disassembly of nuclear envelope during mitosis.

Cyclin Accumulation

Increase in cyclin levels during S and G2 phases.

Internal Signals

Regulatory signals within the cell affecting division.

External Factors

Environmental influences like nutrients affecting cell division.

Chromosome Missegregation

Incorrect separation of chromosomes during cell division.

Cell Cycle Control System

Network of proteins coordinating cell cycle events.

Experimental Evidence

Data supporting cytoplasmic signals in cell cycle regulation.

Platelet-Derived Growth Factor (PDGF)

Stimulates fibroblast division and wound healing.

Density-Dependent Inhibition

Cells stop dividing when crowded, maintaining a single layer.

Anchorage Dependence

Cells require attachment to divide, linked to extracellular matrix.

Cell Cycle Control System

Regulates cell division based on external signals.

Cancer Cells

Bypass normal cell cycle controls, leading to uncontrolled growth.

HeLa Cells

Immortal cancer cells cultured since 1951, illustrating cell division limits.

Tumor Formation

Transformation of normal cells into benign or malignant tumors.

Metastasis

Spread of cancer cells through lymphatic and blood vessels.

Chemotherapy

Drug treatment targeting rapidly dividing cells, including cancerous ones.

Radiation Therapy

Uses high-energy radiation to damage DNA in localized tumors.

Taxol

Chemotherapeutic agent disrupting mitotic spindle during cell division.

Extracellular Matrix

Provides structural support for cells, crucial for anchorage dependence.

Fibroblast Cells

Connective tissue cells essential for wound healing and culture.

Basic Growth Medium

Contains nutrients like glucose and amino acids for cell culture.

Scanning Electron Microscopy (SEM)

Imaging technique confirming fibroblast presence in PDGF-treated vessels.

Nutrient Limitation

Occurs as cell density increases, affecting growth factor availability.

Immune System Targeting

Typically identifies and attacks transformed cancer cells.

Chromosomal Abnormalities

Cancer cells often exhibit unusual chromosome numbers.

Dysfunctional Metabolism

Abnormal metabolic processes contribute to cancer cell aggressiveness.

Experimental Evidence

Demonstrates PDGF's role in fibroblast proliferation in culture.

Control Vessels

Cultures without PDGF showing no cell division.

Cell Division Techniques

Methods used to study and manipulate cell growth in culture.

Genetic Alterations

Changes affecting cell cycle control, leading to cancer.

Genetic Probability

Predicts trait inheritance from parents to offspring.

Mendelian Genetics

Study of inheritance patterns established by Gregor Mendel.

Phenotypic Ratio

Ratio of observable traits in offspring.

Multiplication Rule

Calculates probability of independent events occurring together.

Addition Rule

Calculates probability of mutually exclusive events occurring.

Monohybrid Cross

Cross involving one trait with two alleles.

Dominant Allele

Allele that expresses its trait in heterozygous condition.

Recessive Allele

Allele that expresses its trait only in homozygous condition.

Punnett Square

Tool for visualizing genetic crosses and outcomes.

Expected Phenotypic Ratio

3:1 ratio for Rr x Rr cross outcomes.

Dihybrid Cross

Cross involving two traits simultaneously, each with two alleles.

Trihybrid Cross

Cross involving three traits, each with two alleles.

Genotype

Genetic makeup of an organism for a trait.

YYRR Genotype Probability

1/16 probability from YyRr x YyRr cross.

YyRR Genotype Probability

1/8 probability from YyRr x YyRr cross.

Recessive Phenotype

Expressed when both alleles are recessive.

Homozygous Recessive

Genotype with two recessive alleles (e.g., rr).

Heterozygous

Genotype with one dominant and one recessive allele.

Complex Genetic Crosses

Involves multiple traits and requires detailed analysis.

Practical Applications

Used in agriculture, medicine, and conservation biology.

Probability Measurement

Ranges from 0 (impossible) to 1 (certain).

Total Probability Rule

Sum of probabilities for all outcomes equals 1.

Hereditary Diseases

Genetic disorders passed from parents to offspring.

Independent Events

Outcomes of one event do not affect another.

Mendel's Law of Independent Assortment

Alleles segregate independently during gamete formation.

Mendel's Law of Segregation

Allele pairs separate during gamete formation.

Monohybrid Cross

Cross involving one trait's alleles.

Dihybrid Cross

Cross involving two traits' alleles simultaneously.

Multiplication Rule

Probability of two independent events occurring together.

Addition Rule

Probability of mutually exclusive events occurring.

Punnett Square

Visual tool for predicting genetic cross outcomes.