Cell Structure and Function

The Cell

This presentation will examine the structure and function of a “typical” cell

The size and shape of a cell is directly related to its function

Cells become specialized by modifying the basic set up/structure. An abundance of one or more kinds of organelles would be the adaptation to the job/function that cell must do.

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Cell Membrane

Structure Phospholipid bilayer, embedded proteins, cholesterol in

animal cells Selectively permeable Porous

Function Separates out from in, provides shape and support,

regulates what materials can enter and leave the cell

Life Processes Absorption, secretion, excretion

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Nucleus

Structure Double phospholipid bilayer, embedded proteins Nucleoplasm – contains DNA, RNA and protein Nucleoli

Function Controls cell activity by directing the production of

protein Carries and transmits genetic information

Life Processes Biosynthesis, reproduction, response

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Chromosomes or Chromatin

Structure Organized DNA, RNA and protein

Function Encodes an organisms genetic information

Life Processes Reproduction, biosynthesis

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Nucleolus

Structure DNA, RNA, protein

Function Transcribes rRNA to make ribosomes out of protein

Life Processes Biosynthesis, response

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Nuclear Membrane / Pores

Structure 2 phospholipid bilayers, protein

Function Outer layer is connected to the endoplasmic reticulum Inner layer encloses the nucleoplasm Pores connect the two layers

Life Processes Involved in reproduction and biosynthesis

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Cytoplasm

Structure All of the molecules and structures needed to carry out

the life processes A fluid medium (cytosol)

Function Creates the environment for all cell activity

Life processes All life processes

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Mitochondria

Strucutre Double phospholipid bilayer, folded compartments

(increased surface area)

Function Organizes and carries out the chemistry of respiration

(AKA the release of energy from food molecules)

Life Processes Respiration

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Ribosomes

Structure rRNA and protein (not membrane bound) Can be attached to the endoplasmic reticulum or free

floating

Function Combines amino acids by reading the genetic code

(mRNA) to build proteins

Life Processes Biosynthesis

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Endoplasmic Reticulum

Structure Folded phospholipid bilayer (increases surface area), protein

Function Smooth (no attached ribosomes)

Builds new membranes for a cell to grow, repair, make new organelles and neutralize poisons

Rough (w/ attached ribosomes) Facilitates protein production

Life Processes Biosynthesis

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Golgi Complex

Structure Stacked discs with a phospholipid bilayer (increases

organization and surface area)

Function Packages and secretes cell products

Life Processes Secretion

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Vacuoles

Structure Phospholipid bilayer, embedded protein

Function Storage chambers Embedded proteins decide what is stored inside In plants, there is usually one large vacuole

Life Processes Possibly food getting or excretion

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Lysosomes

Structure Phospholipid bilayer, embedded proteins

Function Storage of digestive enzymes Destroys foreign proteins, unwanted material and aids in

self destruction (apoptosis)

Life Processes Digestion

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Peroxisomes

Structure Phospholipid bilayer, embedded protein

Function Breaks down lipids byproduct = hydrogen peroxide

peroxidase breaks down hydrogen peroxide into water

Life Processes Digestion

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Microfilaments

Structure Thin, solid protein fibers

Function Creates the cytoskeleton (support for the cell)

Life Processes none

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Microtubules

Structure Small, hollow tubes made of protein

Function Form a variety of cell structures including…

Centrioles Spindle fibers Cilia and Flagella

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Centrioles

Structure Microtubules

Function Serve as an anchor for spindle fibers to attach when

pulling apart chromosomes in cell division (only in animal cells)

Life Processes Reproduction

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Cell Wall

Structure Mostly cellulose (plants), Chitin (fungus)

Function Structural support and protection

Life Processes none

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Plastids

A variety of organelles found only in autotrophic cells Chloroplasts

Contain chlorophyll Harnesses the energy from sunlight to make food

(photosynthesis) Chromoplasts

Color pigments Reproduction (attract pollinators)

Leucoplasts Starch storage

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