Understanding the Cell Cycle and Mitosis

Cell Cycle

Series of events in a cell's life.

Interphase

Phase where the cell prepares for division.

M Phase

Phase where cell division occurs.

G1 Phase

Cell growth and preparation for DNA replication.

S Phase

DNA replication occurs, doubling genetic material.

G2 Phase

Final preparations for mitosis, checking DNA.

Mitosis

Process of nuclear division into two nuclei.

Cytokinesis

Division of cytoplasm, resulting in two cells.

Sister Chromatids

Identical copies of a chromosome after replication.

Centromere

Region where sister chromatids are joined together.

Chromatin

Loose DNA form during interphase.

Condensed Chromosomes

Tightly packed DNA visible during mitosis.

G0 Phase

Resting state where cells do not divide.

Apoptosis

Programmed cell death for damaged cells.

Cell Cycle Checkpoints

Regulatory points ensuring proper cell cycle progression.

Benign Tumor

Non-cancerous growth that does not spread.

Malignant Tumor

Cancerous growth that invades surrounding tissues.

Mutation

Change in DNA sequence affecting gene function.

Carcinogens

Substances that can cause cancer by inducing mutations.

Radiation Therapy

Cancer treatment using high-energy radiation.

Chemotherapy

Use of drugs to kill rapidly dividing cancer cells.

Genome

Complete set of an organism's genetic material.

Diploid

Cells with two sets of chromosomes (2n).

Haploid

Cells with one set of chromosomes (n).

Somatic Cell

Any body cell excluding gametes.

Gamete

Reproductive cell (sperm or egg).

Trisomy

Condition of having three copies of a chromosome.

Meiosis Purpose

Process to produce haploid gametes for reproduction.

Human Chromosome Count

Humans have 46 chromosomes in somatic cells.

Homologous Chromosomes

Chromosome pairs, one from each parent.

Down Syndrome

Genetic disorder caused by trisomy of chromosome 21.

Karyotype

Visual representation of an individual's chromosomes.

Centrioles Role

Organize spindle fibers during mitosis.

Prophase Events

Nuclear membrane dissolves, DNA condenses, spindle forms.

Metaphase Events

Chromosomes align at cell equator, spindle fibers attach.

Anaphase Events

Sister chromatids separate and move to poles.

Telophase Events

Nuclear membranes reform, DNA decondenses, spindle fibers disassemble.

Mitosis

Single division producing two identical daughter cells.

Meiosis

Two divisions producing four genetically diverse gametes.

Gametes

Reproductive cells with half the chromosome number.

DNA replication

Occurs before both mitosis and meiosis divisions.

Maternal chromosomes

Chromosomes inherited from the mother.

Paternal chromosomes

Chromosomes inherited from the father.

Crossing-over

Exchange of genetic material between homologous chromosomes.

Genetic variety

Diversity in gametes due to crossing-over and independent assortment.

Nondisjunction

Failure of chromosomes to separate properly during division.

Germ line cells

Cells that give rise to gametes.

Gonads

Organs producing gametes; ovaries and testes.

Ovulation

Release of an egg from the ovary.

Fertilization

Union of sperm and egg to form a zygote.

Zygote

Fertilized egg that develops into an embryo.

Blastocyst

Early stage of embryo before implantation.

Embryo

Developing organism from fertilization to 8 weeks.

Fetus

Developing human from 8 weeks to birth.

Placenta

Organ providing nutrients and waste exchange during pregnancy.

Amniotic Sac

Fluid-filled membrane protecting the embryo.

Gestation period

Average human pregnancy lasts about 40 weeks.

Identical twins

Develop from a single fertilized egg splitting.

Fraternal twins

Develop from two separate fertilized eggs.

Pollination

Transfer of pollen from anther to stigma.

Cross-pollination

Pollen transfer between different plants.

Self-pollination

Pollen transfer within the same plant.

Gregor Mendel

Father of genetics; studied pea plants.

Traits

Specific characteristics that vary among organisms.

Heredity

Passing of traits from parents to offspring.

Genetics

Scientific study of heredity and variation.

Genes

Units of DNA coding for specific proteins.

Allele

Different forms of a gene.

Genotype

Combination of alleles for a specific gene.

Phenotype

Observable traits of an organism.

Dominant allele

Always expressed when present in genotype.

Recessive allele

Expressed only when two copies are present.

Heterozygous

Genotype with two different alleles for a gene.

Homozygous

Genotype with two identical alleles for a gene.

Non-Mendelian trait

Trait not following Mendelian inheritance patterns.

Incomplete dominance

Blending of traits in heterozygous individuals.

Codominance

Both alleles fully expressed in heterozygous individuals.

Polygenic trait

Trait controlled by multiple genes.

Polygenic inheritance

Multiple genes influence a single trait's phenotype.

Cell cycle

Series of events for cell growth and division.

M phase

Phase where cell divides into two daughter cells.

G1 phase

Cell grows and synthesizes proteins.

G2 phase

Cell prepares for mitosis, checks DNA integrity.

Mitosis

Process of nuclear division resulting in two nuclei.

Cytokinesis

Division of cytoplasm, forming two separate cells.

Sister chromatids

Identical copies of a chromosome joined at centromere.

Centromere

Region where sister chromatids are joined.

Chromatin

Loose DNA form during interphase, allowing gene expression.

G0 phase

Resting state where cells exit the cycle.

Apoptosis

Programmed cell death to eliminate damaged cells.

Mutation

Change in DNA sequence affecting genetic information.

Radiation therapy

Cancer treatment using high-energy radiation to kill cells.

Genome

Complete set of genetic material in an organism.

Diploid

Cell with two complete sets of chromosomes.

Haploid

Cell with one complete set of chromosomes.

Gamete

Reproductive cell, either sperm or ovum.

Sperm cell

Male gamete responsible for fertilization.

Ovum

Female gamete involved in reproduction.

Homologous chromosomes

Pairs of chromosomes with same genes, one from each parent.

Human somatic cells

Contain 46 chromosomes arranged in 23 pairs.