Unit 2 Concept 3

Sperm fertilizes egg -> fertilized egg (zygote) goes through cell division repeatedly -> embryonic stem cells differentiate and become embryo

Specialized: become tissues -> organs -> organ systems

Stem cells: undifferentiated cells that become differentiated into one or more types of specialized cells

Organism: individual member of a species

Organ system: set of organs working together for a common function

Organ: set of tissues working together for a common function

Tissue: group of cells working together for a common function

Cell: most basic unit of life that has all the characteristics of life

Growth and repair

Growth phase

Gap 1, Synthesis, Gap 2

cell grows and makes proteins

DNA replication occurs, doubling chromosomes

more cell growth and protein synthesis

Division phase

Prophase, metaphase, anaphase, telophase

chromosomes condense & are visible as sister chromatids (Xs), nuclear membrane disappears, spindle fibers form out of centrioles

spindle fibers connect to the centromeres, chromosomes line up in the middle of the cell

sister chromatids separate and become individual chromosomes, chromatids move to opposite ends of the cell

chromosomes decondense and start to look like chromatin again, nuclear membrane reforms, spindle fibers break down, cytokinesis begins

division of cytoplasm into 2 individual cells

Plant cells: cell plate forms midway between divided nuclei and gradually develops into a membrane

Animal cells: forms a cleavage furrow that pinches the cell into 2 equal parts

Cell cycle is controlled by a chemical control system that starts and stops

signals that come from the cell’s own nucleus (DNA inside of the cell)

signals that come from outside of the cell (Hormones, nutrients etc)

critical point where stop and go signals can regulate the cycle

internal/external signals activate genes that produce self-destructive enzymes (ex: web fingers/toes)

clumps of cells that divide uncontrollably

abnormal cells that typically remain clustered together, may be harmless and easily removed

cancer cells that break away from the tumor and move to other parts of the body

Biological factors (age, skin type etc)

Lifestyle choices (diet, exposure to UV radiation etc)

Viruses and other infections (HPV)

Exposure to carcinogens (tobacco, asbestos etc)

a process that creates special structures and functions

undifferentiated cells that become differentiated into one or more types of specialized cells

a repeated pattern of growth, DNA duplication and cell division that occurs in eukaryotic cells

one long continuous thread of DNA that consists of thousands of genes and regulatory information

a section of DNA with the instructions for making a protein

two identical chromatids

region of the condensed chromosomes that looks pinched

ends of the DNA molecule

uncontrolled cell division

spreading of disease from one organ to others

cancer causing agents; chemicals that cause cancer by mutating DNA