Biology - Animal Cells, Tissues, Cancer Flashcards
Differences Between Animal and Plant Cells
Plant cells have cell walls, chloroplasts, and one large vacuole. Animal cells have centrioles and multiple small vacuoles.
Cell Cycle
Interphase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis
Interphase
90% of cell cycle
Growth 1: cell grows larger until surface area to volume ratio is unhealthy
Synthesis: DNA duplication
Growth 2: organelles needed for cell division are grown
Prophase
DNA forms chromosomes (two chromatids joined at a centromere), nuclear membrane breaks down, centrioles move to opposite poles, spindle fibres begin to grow
Metaphase
Chromosomes line up at middle, spindle fibres attach to centromeres
Anaphase
Spindle fibres break apart chromatids and pull to opposite poles, forming daughter chromosomes
Telophase
Daughter chromosomes become long and thin again (invisible), nuclear membranes begin to reappear, spindle fibres disappear
Cytokinesis
Cytoplasm and all organelles divide between daughter cells, cell furrow/cell plate forms
Apoptosis
Natural cell death
Different types of cells have different cell cycle lengths (skin cells: 14-28 days, red blood cells: 120 days)
Why is cell division necessary?
Growth, Reproduction, Repair
Cell Differentiation
The process of creating specialized cells:
- All cells start from zygote undergoing mitosis which forms blastocyte
- As embryo develops, cells change shape, form, and functions
- Daughter cells have the same DNA, but different genes may be turned on and off
Factors Causing Specialization
- Cytoplasm Differences: asymmetrical distribution of organelles and other factors in zygote
- Environmental Conditions: variations in temperature and nutrients
- Neighbouring Cells: substances can diffuse from nearby cells
Abnormal Development
Cellular development impacted from chemical contamination of environment
Stem Cells
Cells that can differentiate into different cell types
Types of Stem Cells
- Embryonic Stem Cells: from 5-7 day old embryos –> can differentiate into any cell type
- Adult Stem Cells: exists in some tissues –> can only differentiate into specific cell types
- Induced Pluripotent Stem Cells (iPSC): virus is injected into adult cells to insert additional genes –> can differentiate into any cell type
Heirarchy of Structure in Animals
Specialized Cells –> Tissue –> Organs –> Organ Systems –> Organisms
Tissue
Collection of similar cells that preform a specific function
Epithelial Tissue
Lines the inner and outer surfaces of the body; forms a barrier by connecting cell membranes
Muscular Tissue
Moves the body or organs by contracting and relaxing
Connective Tissue
Strengthens, supports, and protects other tissues (cells are in extracellular matrix)
Nervous Tissue
Made up of neurons with long projections that send and receive signals - coordinates body actions
Cancer
The uncontrolled division and spread of abnormal cells
Tumors
Mass of cells with no apparent function (benign, malignant, metastatic)
Benign Tumors
Harmless, non-cancerous, doesn’t spread
Malignant Tumors
Harmful, potential to spread through body through blood, lymph, or tissues
Metastatic Tumors
Has travelled and grown into other areas
Causes of Cancer
Accumulation of genetic changes and mutations that disrupt instructions given to cells to stop dividing (no apoptosis) - normal cells divide a set amount of time, cancerous cells divide indefinitely
Cancer Treatments
Radiation: high energy waves that kill cancer cells
Chemotherapy: anticancer drugs that kill cancer cells
Surgery: physically removes cancer cells
