Nucleus Cytoplasm Plasma Membrane (A) Generalized Animal

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Nucleus

Cytoplasm

Plasma membrane (a) Generalized animal cell

Nuclear pores

(b) Nucleus 2 Extracellular fluid Glycoprotein Glycolipid (watery environment) Cholesterol

Sugar group

Polar heads of phospholipid molecules

Bimolecular lipid layer containing proteins Channel

Nonpolar tails of Proteins Filaments of phospholipid molecules cytoskeleton Cytoplasm (watery environment)

3 Microvilli Tight (impermeable) junction

Desmosome (anchoring junction)

Plasma membranes of adjacent cells

Connexon

Underlying Extracellular Gap basement space between (communicating) membrane cells junction 4 Chromatin Nuclear envelope Nucleolus Nucleus

Plasma Smooth endoplasmic membrane reticulum

Cytosol

Lysosome

Mitochondrion Rough endoplasmic reticulum Centrioles Ribosomes

Golgi apparatus

Secretion being released Microtubule from cell by exocytosis Peroxisome

Intermediate filaments 5 Ribosome mRNA

1 As the protein is synthesized on the ribosome, Rough ER it migrates into the rough ER tunnel system.

2 1 3 2 In the tunnel, the protein folds into its functional shape. Short sugar chains may be attached to the protein (forming a glycoprotein). Protein

3 The protein is packaged in a tiny membranous sac called a transport vesicle. Transport 4 vesicle buds off 4 The transport vesicle buds from the rough ER and travels to the Golgi apparatus for further processing.

Protein inside transport vesicle

Membrane Lysosome fuses with ingested substances. Transport vesicle

Golgi vesicle containing digestive enzymes becomes a lysosome. Pathway 3

Pathway 2 Golgi vesicle containing Golgi membrane components apparatus Secretory vesicles fuses with the plasma Pathway 1 membrane and is Proteins incorporated into it. Golgi vesicle containing proteins to be secreted Plasma membrane becomes a secretory Secretion by vesicle. exocytosis Extracellular fluid

Tubulin subunits Fibrous subunits Actin subunit

7 nm 10 nm 25 nm

Microfilaments form the blue Intermediate filaments form Microtubules appear as gold batlike network. the purple network surrounding networks surrounding the cells’ the pink nucleus. pink nuclei.

Nucleus Erythrocytes (a) Cells that connect body parts

(b) Cells that cover and line body organs

Nucleus

(d) Cell that stores nutrients

Pseudopods

(e) Cell that fights disease

Nerve cell

Nucleus

(f) Cell that gathers information and controls body functions

Sperm (g) Cell of reproduction

Cytoplasm

(b) Osmosis, diffusion of water through a specific channel protein (aquaporin) © 2018 Pearson Education, Inc. 18 (a) RBC in isotonic solution (b) RBC in hypertonic solution (c) RBC in hypotonic solution

Lipid bilayer

(c) Facilitated (d) Facilitated diffusion via diffusion through protein carrier specific for one a channel protein; chemical; binding of substrate mostly ions, causes shape change in selected on basis transport protein of size and charge

Extracellular fluid

Na+ + Na K+

Na+-K+ pump Na+

Na+

Na+ K+

P i Na+ K+ + ATP Na 1 2 3 K+ ADP

1 Binding of cytoplasmic Na+ 2 The shape change expels 3 Loss of phosphate restores to the pump protein stimulates Na+ to the outside. Extracellular the original shape of the pump phosphorylation by ATP, which K+ binds, causing release of the protein. K+ is released to the causes the pump protein to inorganic phosphate group. cytoplasm, and Na+ sites are change its shape. ready to bind Na+ again; the cycle repeats.

Cytoplasm

1 The membrane- bound vesicle Vesicle migrates to the docking plasma membrane. protein Molecule to be secreted Secretory vesicle Cytoplasm

Fusion pore formed 2 There, docking proteins on the vesicle and plasma membrane bind, the vesicle and Fused membrane fuse, and docking a pore opens up. proteins

3 Vesicle contents are released to the cell exterior.

(a) The process of exocytosis © 2018 Pearson Education, Inc. 23 Extracellular fluid Cytoplasm Plasma membrane Vesicle Lysosome 1 Vesicle forms and fuses with lysosome Release of for digestion. 2A contents to cytosol 2 Transport to plasma membrane and exocytosis of vesicle contents

Detached vesicle Ingested 2B substance

3 Membranes and receptors (if present) recycled to Pit plasma membrane

Pseudopod (b) Phagocytosis

Target molecule

New Old Newly strand Old (template) (template) synthesized forming strand strand strand DNA of one sister chromatid © 2018 Pearson Education, Inc. 27 Centrioles Chromatin Centrioles Spindle Centromere microtubules

Forming mitotic spindle Centromere

Plasma Nuclear Chromosome, Fragments of membrane envelope consisting of two nuclear envelope sister chromatids Nucleolus

Interphase Early prophase Late prophase

Metaphase Nucleolus plate forming

Cleavage furrow

Nuclear Mitotic Sister Daughter envelope spindle chromatids chromosomes forming

Nucleus DNA Cytoplasm (site of transcription) gene (site of translation)

1 mRNA specifying one polypeptide is made from a gene on the DNA template by an enzyme (not shown).

2 mRNA leaves nucleus Amino and attaches to ribosome, mRNA acids and translation begins.

Nuclear pore

Nuclear membrane Correct amino acid attached to Synthetase each type of enzyme tRNA by an enzyme

IIe 3 Incoming tRNA recognizes a complementary Growing mRNA codon calling for its polypeptide Met amino acid by temporarily chain binding its anticodon to the Gly 4 As the ribosome moves codon. along the mRNA, a new amino Ser tRNA “head” acid is added to the growing Phe bearing anticodon protein chain. Ala Peptide bond

5 Released tRNA reenters the cytoplasmic pool, ready to be recharged Large ribosomal subunit with a new amino acid.

Codon Direction of ribosome Small ribosomal subunit reading; ribosome Portion of moves the mRNA strand mRNA already along sequentially translated as each codon is read.

Basal Simple surface

Apical surface

Cuboidal

Columnar (b) Classification based on cell shape © 2018 Pearson Education, Inc. 31 Number of layers Cell shape One layer: simple epithelial More than one layer: stratified tissues epithelial tissues Squamous Diffusion and filtration Secretion in Protection serous membranes

Cuboidal Secretion and absorption; ciliated types Protection; these tissue types are rare propel mucus or reproductive cells in humans Columnar Secretion and absorption; ciliated types propel mucus or reproductive cells

Transitional No simple transitional epithelium exists Protection; stretching to accommodate distension of urinary structures

Nucleus of Nuclei of squamous squamous epithelial cell epithelial cells

Basement membrane Photomicrograph: Simple squamous epithelium forming part of the alveolar (a) Diagram: Simple squamous (air sac) walls (275×).

Photomicrograph: Simple cuboidal (b) Diagram: Simple cuboidal epithelium in kidney tubules (250×).

Simple columnar epithelial cell

Basement Basement membrane membrane

Photomicrograph: Simple columnar (c) Diagram: Simple columnar epithelium of the small intestine (575×).

Basement Nuclei of membrane pseudostratified cells do not line up Connective tissue

Photomicrograph: Pseudostratified (d) Diagram: Pseudostratified (ciliated) ciliated columnar epithelium lining columnar the human trachea (560×).

Stratified squamous epithelium Stratified squamous epithelium

Basement Basement membrane membrane Connective Photomicrograph: Stratified tissue squamous epithelium lining of (e) Diagram: Stratified squamous the esophagus (140×).

Transitional Basement epithelium membrane Connective tissue

Photomicrograph: Transitional epithelium lining of the bladder, relaxed state (270×); surface rounded cells (f) Diagram: Transitional flatten and elongate when the bladder fills with urine.

Lacunae

(a) Diagram: Bone Photomicrograph: Cross-sectional view of bone (165×).

Chondrocyte in lacuna

Lacunae Matrix

(b) Diagram: Hyaline cartilage Photomicrograph: Hyaline cartilage from the trachea (400×).

Chondro- cytes in lacunae Collagen fiber Collagen fibers

Tendon

Collagen fibers

Collagen fibers Nuclei of Nuclei of fibroblasts fibroblasts

(d) Diagram: Dense fibrous Photomicrograph: Dense fibrous connective tissue from a tendon (475×).

Collagen fibers

Elastic Fibroblast fibers of nuclei matrix Nuclei of fibroblasts

Collagen fibers (e) Diagram: Areolar Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (270×).

Vacuole containing fat droplet Nuclei of fat cells

Vacuole containing fat droplet

(f) Diagram: Adipose Photomicrograph: Adipose tissue from the subcutaneous layer beneath the skin (570×).

White blood cell (lymphocyte) Reticular cell Reticular fibers Blood cell Reticular fibers

(g) Diagram: Reticular Photomicrograph: Dark-staining network of reticular connective tissue (400×).

Neutrophil (white blood cell)

White Red blood blood cell cells

Monocyte Red (white blood blood cells cell) (h) Diagram: Blood Photomicrograph: Smear of human blood (1290×)

Part of muscle fiber

(a) Diagram: Skeletal muscle Photomicrograph: Skeletal muscle (195×).

Nucleus

(b) Diagram: Cardiac muscle Photomicrograph: Cardiac muscle (475×).

Smooth muscle cell

Nuclei of Spinal neuroglia cord (supporting cells)

Nuclei of Cell body neuroglia of neuron (supporting cells) Cell body Neuron of neuron processes

Neuron processes Diagram: Nervous tissue Photomicrograph: Neurons (320×)

Muscle tissue: Contracts to cause movement Hallmarks: irritable, contractile • Muscles attached to bones (skeletal) • Muscles of heart wall (cardiac) • Muscles of walls of hollow organs (smooth)

Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters Hallmarks: one free (apical) surface, avascular • Lining of GI tract and other hollow organs • Skin surface (epidermis)

Connective tissue: Supports, protects, binds other tissues together Hallmarks: extracellular matrix, varying vascularity • Cartilage • Bones • Tendons • Fat and other soft padding tissue