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BIOB32H3 Lecture Notes - Resting Potential, Ubiquitin, Meiosis

Biological Sciences
Course Code
Kenneth Welch

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The Cellular Level of Organization
An Introduction to Cells
The cell theory states:
Cells are the building blocks of all plants and animals
Cells are produced by the division of preexisting cells
Cells are the smallest units that perform all vital physiological functions
Each cell maintains homeostasis at the cellular level
Homeostasis at higher levels reflects combined, coordinated action of many cells
Cell biology
Cytology, the study of the structure and function of cells
The human body contains both somatic and sex cells
A typical cell
Is surrounded by extracellular fluid, which is the interstitial fluid of the tissue
Has an outer boundary called the cell membrane or plasma membrane
The Cell Membrane
Cell membrane functions include:
Physical isolation
Regulation of exchange with the environment
Structural support
The cell membrane is a phospholipid bilayer with proteins, lipids and
Membrane proteins include:
Integral proteins
Peripheral proteins
Anchoring proteins
Recognition proteins
Receptor proteins
Carrier proteins
Membrane carbohydrates form the glycocalyx
The Cytoplasm
The cytoplasm contains:
The fluid (cytosol)
The organelles the cytosol surrounds

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Nonmembranous organelles are not enclosed by a membrane and always in touch
with the cytosol
Cytoskeleton, microvilli, centrioles, cilia, ribosomes, proteasomes
Membranous organelles are surrounded by lipid membranes
Endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, mitochondria
Cytoskeleton provides strength and flexibility
Intermediate filaments
Thick filaments
increase surface area
Direct the movement of chromosomes during cell division
Organize the cytoskeleton
Cytoplasm surrounding the centrioles is the centrosome
Is anchored by a basal body
Beats rhythmically to move fluids across cell surface
Are responsible for manufacturing proteins
Are composed of a large and a small ribosomal subunit
Contain ribosomal RNA (rRNA)
Can be free or fixed ribosomes
Remove and break down damaged or abnormal proteins
Require targeted proteins to be tagged with ubiquitin
Endoplasmic reticulum
Intracellular membranes involved in synthesis, storage, transportation and
Forms cisternae
Rough ER (RER) contains ribosomes
Forms transport vesicles
Smooth ER (SER)
Involved in lipid synthesis
Golgi Apparatus
Forms secretory vesicles
Discharged by exocytosis
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