BIOLOGY Life on Earth WITH PHYSIOLOGY Tenth Edition

BIOLOGY Life on Earth WITH PHYSIOLOGY Tenth Edition Audesirk Byers 4 Cell Structure and Function Lecture Presentations by Carol R. Anderson Westwood College, River Oaks Campus © 2014 Pearson Education, Inc.

Chapter 4 At a Glance § 4. 1 What Is the Cell Theory? § 4. 2 What Are the Basic Attributes of Cells? § 4. 3 What Are the Major Features of Eukaryotic Cells? § 4. 4 What Are the Major Features of Prokaryotic Cells? © 2014 Pearson Education, Inc.

4. 1 What Is the Cell Theory? § The cell theory states that cells are the basic units of life – Three principles comprise the cell theory – Every living organism is made of one or more cells – The smallest organisms are single cells, and cells are the functional units of multicellular organisms – All cells arise from preexisting cells © 2014 Pearson Education, Inc.

4. 2 What Are the Basic Attributes of Cells? – Most cells range in size from about 1 to 100 micrometers in diameter – Diffusion is the process whereby molecules dissolved in liquids move from a highly concentrated region to a lesser concentrated region – Cells need to exchange nutrients and wastes with the environment – No part of the cell can be too far away from the external environment © 2014 Pearson Education, Inc.

Figure 4 -1 Relative sizes tallest trees Size 100 m visible with unaided human eye 10 m 1 m 10 cm adult human chicken egg 1 cm 1 mm visible with light microscope frog embryo 100 m 10 m most eukaryotic cells 1 m 10 nm 1 nm visible with special electron microscope 100 nm visible with conventional electron microscope mitochondrion most prokaryotic cells virus proteins diameter of DNA double helix Units of measurement: 0. 1 nm © 2014 Pearson Education, Inc. atoms 1 meter (m) 39. 37 inches 1 centimeter (cm) 1/100 m 1 millimeter (mm) 1/1, 000 m 1 micrometer ( m) 1/1, 000 m 1 nanometer (nm) 1/1, 000, 000 m

4. 2 What Are the Basic Attributes of Cells? § All cells share common features – Include plasma membrane – Include cytoplasm – Use DNA as hereditary blueprint – Use RNA to copy the blueprint and guide construction of cell parts © 2014 Pearson Education, Inc.

4. 2 What Are the Basic Attributes of Cells? § All cells share common features (continued) – The plasma membrane encloses the cell and allows interactions between the cell and its environment – This structure is composed of lipid, protein, and carbohydrate molecules, and regulates the passage of ions and molecules in and out of cells © 2014 Pearson Education, Inc.

Figure 4 -2 The plasma membrane interstitial fluid (outside) carbohydrate glycoprotein A phospholipid bilayer helps to isolate the cell’s contents Proteins help the cell communicate with its environment channel protein membrane protein cytoskeleton cytosol © 2014 Pearson Education, Inc.

4. 2 What Are the Basic Attributes of Cells? § All cells share common features (continued) – All cells contain cytoplasm – The cytoplasm consists of all the fluid and structures that lie inside the plasma membrane but outside of the nucleus – The fluid portion of the cytoplasm (cytosol) contains water, salts, and organic molecules – Most of the cell’s metabolic activities occur in the cell cytoplasm © 2014 Pearson Education, Inc.

Figure 4 -3 A generalized animal cell microfilaments nuclear envelope nuclear pore nucleus chromatin (DNA) nucleolus cytosol microtubules (cytoskeleton) flagellum (propels sperm cell) basal body rough endoplasmic reticulum vesicle intermediate filaments (cytoskeleton) cytoplasm Golgi apparatus centriole ribosomes on rough ER polyribosome lysosome smooth endoplasmic reticulum vesicles releasing substances from the cell mitochondrion © 2014 Pearson Education, Inc. plasma membrane free ribosome

Figure 4 -4 A generalized plant cell nucleus microtubules (cytoskeleton) nuclear envelope nuclear pore chromatin nucleolus ribosomes intermediate filaments (cytoskeleton) cell walls of adjoining plant cells chloroplast cytoplasm rough endoplasmic reticulum smooth endoplasmic reticulum Golgi apparatus central vacuole vesicle mitochondrion cell wall © 2014 Pearson Education, Inc. plasmodesmata cytosol plastid free ribosome plasma membrane

4. 2 What Are the Basic Attributes of Cells? § All cells share common features (continued) – All cells use DNA as a hereditary blueprint and RNA to copy the blueprint and guide construction of cell parts – All cells use DNA (deoxyribonucleic acid) as a hereditary blueprint – All cells use RNA (ribonucleic acid) to copy the blueprint and to guide construction of proteins © 2014 Pearson Education, Inc.

4. 2 What Are the Basic Attributes of Cells? § There are two basic types of cells: prokaryotic and eukaryotic – Prokaryotic (“before the nucleus”) cells form the bodies of bacteria and archaea, the simplest forms of life – Eukaryotic (“true nucleus”) cells form the bodies of animals, plants, fungi, and protists © 2014 Pearson Education, Inc.

4. 2 What Are the Basic Attributes of Cells? § There are two basic types of cells: prokaryotic and eukaryotic (continued) – The cytoplasm of eukaryotic cells includes a variety of organelles, such as the nucleus and mitochondria – The cytoskeleton gives shape and organization to the cytoplasm of eukaryotic cells © 2014 Pearson Education, Inc.

Table 4 -1 © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? – Eukaryotic cells make up the bodies of animals, plants, protists, and fungi – Eukaryotic cells are very diverse – The cytoplasm of eukaryotic cells houses the nucleus and mitochondria that perform specific functions within the cell – Plant and animal cells have structures that are unique to each type of cell © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Some eukaryotic cells are supported by cell walls – The outer surfaces of plants, fungi, and some protists are covered with nonliving, relatively stiff coatings called cell walls – Plant cell walls are composed of cellulose and other polysaccharides – Fungal cell walls are made of polysaccharides and chitin © 2014 Pearson Education, Inc.

Eukaryotic cells differ from prokaryotic cells because the former possess a number of membrane-enclosed organelles that perform specific cell functions. Nucleus: contains DNA Mitochondria: produce energy Endoplasmic reticulum: synthesizes membrane components and lipids Golgi apparatus: molecule sorting center Lysosomes: digest cellular membranes or defective organelles Microtubules: make up the cytoskeleto © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Some eukaryotic cells are supported by cell walls (continued) § Plant cells are surrounded by a cell wall – Plant cells also have plastids and a central vacuole, not found in animal cells § Some animal cells possess vesicles, vacuoles, and cilia, not found in plant cells © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Some eukaryotic cells are supported by cell walls (continued) – Cell walls are porous, allowing oxygen, carbon dioxide, and water carrying dissolved molecules to flow easily through them – The plasma membrane is located just beneath the cell wall © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The cytoskeleton provides shape, support, and movement – Organelles are attached to a network of protein fibers that make up the cytoskeleton – The cytoskeleton is composed of three types of protein fibers – Thin microfilaments – Medium-sized intermediate filaments – Thick microtubules © 2014 Pearson Education, Inc.

Figure 4 -5 The cytoskeleton microtubules (red) intermediate filaments microtubules nucleus microfilaments (blue) Cytoskeleton

4. 3 What Are the Major Features of Eukaryotic Cells? § The cytoskeleton provides shape, support, and movement (continued) – The cytoskeleton regulates the following cell properties: – Cell shape – Cell movement – Organelle movement – Cell division © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Cilia and flagella move the cell through fluid or move fluid past the cell – Both cilia and flagella are hair-like structures that propel cells through fluids or move fluids past cells © 2014 Pearson Education, Inc.

Figure 4 -6 Cilia and flagella protein sidearms central pair of microtubules fused microtubule pair section of cilium Paramecium plasma membrane basal body (extends into cytoplasm) © 2014 Pearson Education, Inc. 0. 1 micrometer cilium

4. 3 What Are the Major Features of Eukaryotic Cells? § Cilia and flagella move the cell through fluid or move fluid past the cell (continued) – The force generated by cilia can be compared to that created by oars on the sides of a rowboat – The force generated by a flagellum can be compared to that created by the engine on a motorboat – Flagella are longer than cilia, and cells with flagella usually have only one or two © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Cilia and flagella move the cell through fluid or move fluid past the cell (continued) – Some unicellular organisms, such as Paramecium, use cilia to swim through water; others use flagella – Ciliated cells line such diverse structures as the gills of oysters, the oviducts of female mammals, and the respiratory tracts of land vertebrates – Most animal sperm rely on flagella for movement © 2014 Pearson Education, Inc.

Figure 4 -7 How cilia and flagella move propulsion of fluid cilia lining trachea mucus-secreting cells Cilium power stroke plasma membrane direction of locomotion Flagellum © 2014 Pearson Education, Inc. return stroke propulsion of fluid continuous propulsion flagellum of human sperm

4. 3 What Are the Major Features of Eukaryotic Cells? § The nucleus, containing DNA, is the control center of the eukaryotic cell – The nucleus is the control center of the eukaryotic cell and has three major parts – Nuclear envelope – Chromatin – Nucleolus © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The nucleus, containing DNA, is the control center of the eukaryotic cell (continued) – The nuclear envelope allows selective exchange of materials – The nucleus is isolated from the rest of the cell by a nuclear envelope that consists of a double membrane perforated by nuclear pores – The membrane is perforated with tiny protein-lined nuclear pores that allow water, ions, and small molecules to pass freely – Passage of proteins, pieces of ribosomes, and RNA are regulated by gatekeeper proteins called the nuclear pore complex that line each nuclear pore © 2014 Pearson Education, Inc.

Figure 4 -8 The nucleus nuclear envelope nucleolus nuclear pores ribosomes nucleus chromatin nuclear

4. 3 What Are the Major Features of Eukaryotic Cells? § The nucleus, containing DNA, is the control center of the eukaryotic cell (continued) – Chromatin consists of strands of DNA associated with proteins – Chromatin is a colored substance contained in the nucleus – During cell division, chromatin becomes compacted into long strands called chromosomes – The chromosomes contain genes that provide a blueprint for a huge variety of proteins © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The nucleus, containing DNA, is the control center of the eukaryotic cell (continued) – Because proteins are synthesized in the cytoplasm, copies of the protein blueprints on DNA must leave the nucleus through the nuclear membrane – To do this, genetic information in DNA is copied into messenger RNA (m. RNA), which travels through the nuclear pores to the cytoplasm, where it directs protein synthesis © 2014 Pearson Education, Inc.

Figure 4 -9 Chromosomes chromatin chromosome © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The nucleus, containing DNA, is the control center of the eukaryotic cell (continued) – The nucleolus is the site of ribosome assembly – Eukaryotic nuclei contain at least one nucleolus, the site of protein synthesis – A ribosome is a small particle composed of ribosomal RNA and proteins – The nucleolus consists of ribosomal RNA, proteins, ribosomes in various stages of synthesis, and DNA © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – Vesicles are membranous sacs transporting molecules to the various regions of the membrane system – Exocytosis is the process whereby vesicles fuse with the plasma membrane as they export their contents outside the cell – Endocytosis is the process whereby the plasma membrane extends and surrounds material just outside the cell, fuses, and then pinches off to form a vesicle inside the cell © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – The endoplasmic reticulum forms membraneenclosed channels within the cytoplasm – The endoplasmic reticulum (ER) is a series of interconnected membranes that form a labyrinth of flattened sacs and channels within the cytoplasm – The rough endoplasmic reticulum and smooth endoplasmic reticulum are the two types of ER – All the proteins and phospholipids of cell membranes are synthesized in the ER © 2014 Pearson Education, Inc.

Figure 4 -11 Endoplasmic reticulum ribosomes smooth ER rough ER smooth ER vesicles Endoplasmic

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – Rough endoplasmic reticulum is studded with ribosomes and produces proteins destined for other membranes or for secretion – Smooth endoplasmic reticulum has no ribosomes, detoxifies drugs, and synthesizes lipids such as steroid hormones made from cholesterol © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – The Golgi apparatus modifies, sorts, and packages important molecules – The Golgi apparatus modifies some molecules, such as adding a carbohydrate group to proteins, and making glycoproteins; it breaks some proteins into smaller peptides © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – The Golgi apparatus modifies, sorts, and packages important molecules (continued) – It separates various proteins and lipids received from the ER according to their destinations – It packages the finished molecules into vesicles that are then transported to other parts of the cell or to the plasma membrane for export © 2014 Pearson Education, Inc.

Figure 4 -12 The Golgi apparatus Protein-carrying vesicles from the ER merge with the

Figure 4 -13 A protein is manufactured and exported (interstitial fluid) Vesicles merge with the plasma membrane and release antibodies into the interstitial fluid (cytosol) vesicles Completed glycoprotein antibodies are packaged into vesicles on the opposite side of the Golgi apparatus Vesicles fuse with the Golgi apparatus, and carbohydrates are added as the protein passes through the compartments The protein is packaged into vesicles and travels to the Golgi apparatus forming vesicle Antibody protein is synthesized on ribosomes and is transported into channels of the rough ER © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § The eukaryotic cytoplasm contains membranes that form the endomembrane system (continued) – Lysosomes serve as the cell’s digestive system – Digestive proteins are made in the rough ER, travel through the Golgi, and are packaged in membraneenclosed vesicles as lysosomes – A lysosome fuses with a food vacuole and digests food into basic nutrients © 2014 Pearson Education, Inc.

Figure 4 -14 Formation and function of lysosomes and food vacuoles via the endomembrane system (interstitial fluid) (cytosol) food vacuoles A lysosome fuses with a food vacuole, and the enzymes digest the food The enzymes are delivered to the lysosome in vesicles lysosome The Golgi apparatus modifies the enzymes for export to the lysosomes Golgi apparatus digestive enzymes The enzymes are packaged into vesicles and travel to the Golgi apparatus Digestive enzymes are synthesized on ribosomes and travel through the rough ER © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Vacuoles serve many functions, including water regulation, storage, and support (continued) – Plant cells have central vacuoles – A large central vacuole occupies three-quarters or more of the volume of most mature plant cells and has several functions – Central vacuoles provide support for plant cells – Turgor pressure (water pressure), within the vacuole, pushes the fluid portion of the cytoplasm up against the cell wall © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Mitochondria extract energy from food molecules, and chloroplasts capture solar energy – All eukaryotic cells have mitochondria that capture energy stored in sugar by producing high-energy ATP molecules – The cells of plants also have chloroplasts, which can capture energy directly from sunlight and store it in sugar molecules – Biologists believe that both mitochondria and chloroplasts evolved from prokaryotic bacteria that became incorporated into the cytoplasm of other prokaryotic cells (endosymbiont hypothesis) © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Mitochondria extract energy from food molecules, and chloroplasts capture solar energy (continued) – Mitochondria are organelles that function as “powerhouses of the cell” – Mitochondria extract energy from food molecules – The extracted energy is stored in high-energy bonds of ATP – The energy extraction process involves anaerobic (“without oxygen”) and aerobic (“with oxygen”) reactions © 2014 Pearson Education, Inc.

4. 3 What Are the Major Features of Eukaryotic Cells? § Mitochondria extract energy from food molecules, and chloroplasts capture solar energy (continued) – The inner membrane is folded into cristae – The intermembrane compartment lies between inner and outer membranes – The matrix space is within the inner membrane © 2014 Pearson Education, Inc.

Figure 4 -16 A mitochondrion outer membrane inner membrane intermembrane space matrix cristae 0.

4. 3 What Are the Major Features of Eukaryotic Cells? § Mitochondria extract energy from food molecules, and chloroplasts capture solar energy (continued) – Chloroplasts are the sites of photosynthesis – Chloroplasts are specialized organelles surrounded by a double membrane – The outer membrane separates the organelle from the cytoplasm – The inner membrane encloses the fluid stroma and contains stacked, hollow, membranous sacs (grana) made of individual thylakoids © 2014 Pearson Education, Inc.

Figure 4 -17 A chloroplast outer membrane inner membrane stroma thylakoid channel interconnecting thylakoids

4. 3 What Are the Major Features of Eukaryotic Cells? § Mitochondria extract energy from food molecules, and chloroplasts capture solar energy (continued) – Chloroplasts are the sites of photosynthesis (continued) – The thylakoid membranes contain the green pigment chlorophyll and other pigments, which capture sunlight and make sugar from CO 2 and water (photosynthesis) © 2014 Pearson Education, Inc.

Prokaryotic cells § A generalized prokaryotic cell chromosome (nucleoid region) ribosomes food granule prokaryotic flagellum cell wall cytoplasm © 2014 Pearson Education, Inc. plasma membrane Fig. 4 -11

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells are small and possess specialized surface features § Prokaryotic cells have fewer specialized structures within their cytoplasm © 2014 Pearson Education, Inc.

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells are small and possess specialized surface features (continued) – Most prokaryotic cells (bacteria) are less than 5 µm long, with a simple internal structure compared to eukaryotic cells – They usually have a stiff cell wall – Prokaryotic cells can take several shapes – Rod-shaped bacilli – Spiral-shaped spirilla – Spherical cocci © 2014 Pearson Education, Inc.

Figure 4 -19 Prokaryotic cells are simpler than eukaryotic cells chromosome (within the nucleoid region) cell wall plasma membrane ribosomes chromosome (within the nucleoid region) Cocci capsule Internal structure pili ribosomes Spirilla food granule prokaryotic flagellum capsule or slime layer cell wall plasmid (DNA) cytoplasma membrane photosynthetic membranes Generalized prokaryotic cell (bacillus) © 2014 Pearson Education, Inc. Photosynthetic prokaryote

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells are small and possess specialized surface features (continued) – Bacteria secrete polysaccharide coatings called capsules and slime layers outside their cells – Capsules and slime layers are similar except capsules are harder to remove – Capsules and slime layers assist in the formation of bacteria on surface films – Examples include tooth decay, diarrhea, and urinary tract infections – Both protect bacteria and keep them from drying out © 2014 Pearson Education, Inc.

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells are small and possess specialized surface features (continued) – Pili (meaning hairs) are surface protein projections of the cell walls in some bacteria that further enhance adhesion – Attachment pili are short and abundant; they help bacteria adhere to structures – Sex pili are few in number and long; one bacterium’s sex pili binds it to a nearby bacterium of the same type © 2014 Pearson Education, Inc.

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells have fewer specialized cytoplasmic structures than do eukaryotic cells – In the central region of the cell is an area called the nucleoid, which is separate from the cytoplasm – Within the nucleoid is a single, circular chromosome of DNA – Small rings of DNA (plasmids) are located in the cytoplasm © 2014 Pearson Education, Inc.

4. 4 What Are the Major Features of Prokaryotic Cells? § Prokaryotic cells have fewer specialized cytoplasmic structures than do eukaryotic cells (continued) – Prokaryotic cells have no nuclear membrane or membrane-bound organelles present – Some have internal membranes used to capture light – The cytoplasm may contain food granules and ribosomes, the latter with a function similar to that of ribosomes in eukaryotic cells © 2014 Pearson Education, Inc.