Cells and Tissues

Cells and Tissues

Two Types of Cells

• Prokaryotic– Domains bacteria and archaea

• No nucleus or membranous organelles• Typically small < 10m• Single circular chromosome

• Eukaryotic– Domain eukarya

• Have a nucleus (sometimes more than 1)• Have numerous membranous organelles• Larger than 20 m (usually >100 m)• Multiple, linear chromosomes within nucleus

Animal Cell

Nucleus• Houses chromosomes - DNA• Transcription – production of RNA from DNA

Gene ExpressionDNA

transcribed

RNA

translated

Protein

Chromosome Structure

• Each chromatid is a DNA double helix

• Aggregate of genes

Chromosome

• Chromosomes attach to microtubules to be separated during cell division

• Each daughter cell receives 1 chromatid of each chromosome

Sister

Mitosis

Cell Membrane

• Encloses cell• Regulates entry/exit of materials

Endoplasmic Reticulum

• Ribosomes – protein synthesis• ER – processing of proteins

Golgi Apparatus

• Processing of proteins for secretion

Production & Secretion of Proteins

Mitochondrion

• Production of ATP • ATP used to activate proteins

Major Tissue Types

Muscle Tissue

• 3 major types– Cardiac– Skeletal (striated)– Smooth

• Major proteins– Contractile proteins

• Actin• Myosin

Muscle Tissue: Skeletal• Multinucleated cells

Muscle Tissue: Cardiac

• Striations, but unfused cells

Muscle Tissue: Smooth• Mononucleate• Two layers – circumferential & longitudinal

Connective Tissues

• Adipose• Areolar• Cartilage• Bone• Blood

• Extracellular matrix– Collagen, elastin– Collagen, hydroxyapatite– Plasma proteins (fibrinogen, immunoglobulins,

albumin, HDL/LDL, etc)

Connective Tissue: Areolar

Connective Tissue: Adipose

Connective Tissues: Cartilage & Bone

Connective Tissue: Blood

• RBCs• WBCs

Epithelial Tissue

• Tightly connected cells• Line exterior of body • Line interior of cavities

– Gut, blood vessels, lymph vessels, glands• Secretion

– Sweat– Digestive enzymes– Milk

Epithelial Tissues

Neural Tissue

• Neurons• Glia