exam 4

Cell Theory

States that all cells come from pre-existing cells.

Asexual Reproduction

Occurs when one parent produces genetically identical offspring.

Binary Fission

Method of reproduction in prokaryotes where one cell splits into two.

Interphase

Stage between cell divisions, consisting of G1, S, and G2 phases.

Mitosis

Division of the nucleus during the mitotic phase of the cell cycle.

Cytokinesis

Division of the cytoplasm following mitosis.

Chromatin

Loose, unraveled DNA visible when the cell is not dividing.

Chromosomes

Highly condensed DNA structures visible during cell division.

Sister Chromatids

A pair of identical chromosomes held together by a centromere.

Homologous Chromosomes

Chromosomes of the same number from each parent.

Diploid

Cells with two sets of chromosomes (2N).

Haploid

Cells with one set of chromosomes (N).

Centrioles

Organelles used in cell division.

G1 Checkpoint

Checks for errors in DNA before cell division.

G2 Checkpoint

Ensures DNA has been properly replicated.

M Checkpoint

Ensures chromosomes are correctly aligned before mitosis continues.

Apoptosis

Programmed cell death when errors cannot be fixed.

Senescence

Aging of cells due to the shortening of telomeres.

G0 Phase

Cells that continue normal functions but do not replicate.

Cancer

Uncontrolled cell growth and division.

Carcinogenesis

The development of cancer.

Tumor

Accumulation of cancerous cells.

Angiogenesis

Formation of new blood vessels to supply a tumor.

Metastasis

Spread of cancer cells to other areas of the body.

Proto-oncogenes

Genes that promote cell cycle and inhibit apoptosis.

Tumor Suppressor Genes

Genes that inhibit the cell cycle and promote apoptosis.

Meiosis

Process that reduces chromosome number and produces genetically unique gametes.

Alleles

Alternate forms of a gene.

Genotype

The genetic makeup of an individual.

Phenotype

The observable traits of an individual.

Punnett Square

A tool used to predict genetic combinations in offspring.

Mendel’s Law of Segregation

States that alleles segregate during gamete formation.

Mendel’s Law of Independent Assortment

States that allele pairs segregate independently.

Autosomal Dominant Disorders

Disorders caused by a dominant allele.

Autosomal Recessive Disorders

Disorders caused by a recessive allele.

Pedigree

A diagram showing the inheritance pattern of a trait.

Incomplete Dominance

A situation where the heterozygote has an intermediate phenotype.

Codominance

Both alleles are expressed equally in the phenotype.

Polygenic Inheritance

A single trait governed by multiple genes.

Sex-Linked Inheritance

Traits associated with genes found on sex chromosomes.