Cell Structure

Membranes

Functions

Divide cell into compartments

Surfaces that hold enzymes

Regulate passage of molecules in/out of cells/organelles #

Composition

Monolayer or bilayer

Hydrophilic backbone (glycerol and phosphate)

Hydrophobic tail (fatty acid)

Proteins

~60% of the membrane

Extrinsic: large hydrophilic regions

Intrinsic: large hydrophobic regions

Plus oligosaccharides = glycoproteins #

Plus oligosaccharides: glycolipids

Properties

Can grow by fusing vesicles

Exocytosis: using vesicles to excrete materials out the surface membrane to the exterior #

Endocytosis: invagination of outer membrane containing materials needed for the cell

Selectively permeable: certain materials cross membrane easier than others

More permeable to hydrophobic substances

Causes need for facilitated diffusion

EX: inorganic salts, sugars, amino acids

Movement of charged particles

Active transport: membrane protein uses energy and solute concentration to change shape and pump molecules across

Constantly changing, dynamic based on needs of cell

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9781284096040_CH03_FIGF06BC

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Cell Characteristics

Prokaryotic

Eukaryotic

No membrane bound organelles; nucleus, mitochondria, ER, golgi, etc.

Simpler; most archaic line of evolution

Bacteria and Archaea

Plants, animals, fungi, protists

Has membrane bound nucleus #

Presence of organelles

Unicellular Organisms - composed of a single cell

Multicellular Organisms - composed of multiple cells

No division of labor; cell must perform all tasks

Division of labor; more efficient; specialization given to organelles #

Organelles

Plant Cells Only 9781284096040_CH03_FIGF11

Animal and Plant Cells

Animal Cells Only

Lysosomes: contain digestive enzymes, recycles components

Cell round shape

Glyoxysomes: convert stored fats into sugars

Plastids 9781284096040_CH03_TABLE07 #

Cell rectangular shape

Central Vacuole: membrane bound (tonoplast) which stores water, calcium, potassium, pigments, metabolic wastes, etc. #

Amyloplasts: store starch

Chromoplasts: store red or yellow pigment for flowers and fruits

Proplastids: young, meristematic cells

Leucoplasts: colorless plastids

Chloroplasts: chlorophyll rich, carries out photosynthesis, has own DNA

Thykaloids:photosynthetic membrane

Granum: flat vesicles, staked, carry out chemiosmotic phosphorylation

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Aids in cell growth, larger it gets

Protoplasm: all substance of cell, not including cell wall

Nucleus: houses DNA

Plasma Membrane: semipermeable membrane that surrounds protoplasm

Cytosol: liquid substance of protoplasm, not including organelles

Cytoplasm: protoplasm, includes nucleus, vacuoles, and cytoplasm

Central Dogma: DNA --> RNA --> Protein

Nuclear Envelope: inner and outer membrane surrounding nucleus

Nuclear Pores: in envelope, transport materials between nucleus and cytoplasm

Nucleoplasm: substance inside nucleus, includes DNA, histones, RNA, enzymes, nucleic acids, and water

Nucleoli: synthesize ribosomal RNAs

Ribosomes:protein synthesis

Mitochondria: aerobic respiration, ATP synthesis

Crista: folds on inner membrane

Matrix: liquid in between crista and membranes

Has own DNA #

Endoplasmic Reticulum

Peroxisomes: breaks down hydrogen peroxide into water and oxygen

Smooth: lipid synthesis

Rough: ribosomes attached, protein synthesis

Golgi apparatus: collection of dictyosomes, packages materials for transportation

Cytoskeleton

Microtubules: reinforcement of cell shape, helps motility

Composed of;

Examples;

Beta-tubulin: polymerize into tublin

Centrioles: organizes the microtubules of flagella

Alpha-tubulin: polymerize into tubulin

Cilia: used for movement, similar to flagella, only shorter

Flagella: used for locomotion, sperm cells

9+2 arrangement of microtubules in cilia and flagella: 9781284096040_CH03_FIGF31

Basal Body: similar to centrioles #

Microfilaments: actin, movement of organelles other than flagella, cilia, and chromosomes

Cell Wall: plant cells only, layer outside for plasma membrane #

Hemicelluloses: polysaccharides that crosslink cellulose molecules

Primary Cell Wall: plant cells, during division, thin

Microfibril: crystallized cellulose

Secondary Cell Wall: sclerenchyma cells, after division, interior to primary, contains lignin

Fungal cells: do not have cellulose in cell wall, but chitlin, do not contain plastids #