Cell Structures, Functions and Transport

Cell Basics basic unit of structure and function in

living things complex structures

most specialized to perform certain functions coordinated functions critical for survival composed of four basic chemicals

C, O, H, N plus traces of Fe, Na, K, Ca 60% water

Functions of CellStructure defines function.

1. basic unit of life2. protection and support3. movement4. communication5. cell metabolism and energy release6. inheritance

3 main regions1. nucleus2. cytoplasm with organelles3. nuclear membrane

Section 7-2

Figure 7-5 Plant and Animal Cells

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Animal Cell

Animal CellNucleus

the control center holds the DNA – instruction for

building proteins necessary for cell reproduction

nucleus

3 regions of nucleus1. Nuclear membrane – double

membrane with “moat” in between selectively permeable encloses nucleoplasm Outer and inner membranes form pores.

2. Nucleolus: where ribosomes are assembled

3. chromatin – fibers that form dense, rod-like structures (chromosomes) during cell reproduction

composed of DNA and proteins, loosely formed when cell is not dividing

Cytoplasm cellular material outside the nucleus

but within the cell membrane site of most cellular activities composed of 3 major components1. cytosol – semi-transparent fluid

composed mostly of water

2. inclusions chemical substances

present but not functioning types dependent on

function of cell fat droplets in fat cells melanin in the skin

primarily stored substances

3. organelles

Organellesmitochondria

powerhouse of the cell small, sausage-shaped

move, change shape continuously double membrane

inner – smooth outer – folds called cristae

Organelles Fluid enzymes and

cristae breakdown food. Energy is released and

used to form ATP. The more energy a cell

requires, the more mitochondria it has.

liver and muscles

OrganellesRibosomes

tiny round structures site of protein synthesis made up of proteins and one

ribosomal RNA some attached, some free-floating

Organelles3. Endoplasmic Reticulum (ER)

minicirculatory system for cell series of tubules and sacs through

cytoplasm carry substances from one part of cell to

another

Organelles2 Types:

1. Rough ER studded with ribosomes transports proteins made by ribosomes found in pancreas

2. Smooth ER no ribosomes, no protein synthesis cholesterol synthesis metabolize fat, detox drugs found in liver, testes

OrganellesGolgi Apparatus

UPS guys of cell composed of closely packed

membrane-bound sacs packages, modifies, and transports

proteins from rough ER found in salivary glands, pancreas

OrganellesLysosomes

intracellular digestive system contain digestive enzymes engulf bacteria other harmful

substances and get rid of them removed used and worn out cell parts found in white blood cells

Organellesperoxisomes

contain oxydase enzymes to digest fats and detox alcohol, formaldehyde

convert dangerous free radicals into H2O2

can mess up protein and nucleic acid structures

catalase then converts into H2O2 to water

Organellescytoskeleton

provide framework or skeleton of cell shape, support, intracellular transport,

movement made up of protein structures throughout

cytoplasm microtubules, intermediate filaments,

microfilaments

Organellescentrioles

rod-shaped bodies close to nucleus

direct formation of mitotic spindle used in cell division

centrosomes composed of two

centrioles grow into spindle fibers

used during cell division

Organellesvacuoles

membranous sacs holding area for substances entering

the cell

Other Cellular Structurescilia – projections from surface of cell

cylindrical shape ex: move mucus in respiratory system

flagella – longer than cilia usually only one per cell ex: sperm cells

microvilli – extensions on surface of cell membrane

increase surface area for absorption ex: intestines, kidneys