Fig. 3.1 Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Copyright © McGraw-Hill Education. Permission required for reproduction or display. Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Mitochondrion Ribosome Lysosome Free ribosome Lysosome fusing with incoming phagocytic vesicle Rough endoplasmic reticulum Smooth endoplasmic reticulum Phagocytic vesicle Centrosome Centrioles Golgi apparatus Peroxisome Microtubule Secretory vesicles Cilia Microvilli

Table 3.1

Fig. 3.1 Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Copyright © McGraw-Hill Education. Permission required for reproduction or display. Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Mitochondrion Ribosome Lysosome Free ribosome Lysosome fusing with incoming phagocytic vesicle Rough endoplasmic reticulum Smooth endoplasmic reticulum Phagocytic vesicle Centrosome Centrioles Golgi apparatus Peroxisome Microtubule Secretory vesicles Cilia Microvilli

b: ©Don Fawcett/Science Source; c: ©Bernard Gilula/Science Source Fig. 3.13 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Nuclear pores Ribosomes Nucleus Outer membrane Space Nuclear envelope Inner membrane (a) Nucleolus Nuclear envelope Outer membrane of nuclear envelope Interior of nucleus Inner membrane of nuclear envelope Nucleolus Nuclear pores Chromatin (b) TEM 20,000x SEM 50,000x (c) b: ©Don Fawcett/Science Source; c: ©Bernard Gilula/Science Source

Fig. 3.1 Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Copyright © McGraw-Hill Education. Permission required for reproduction or display. Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Mitochondrion Ribosome Lysosome Free ribosome Lysosome fusing with incoming phagocytic vesicle Rough endoplasmic reticulum Smooth endoplasmic reticulum Phagocytic vesicle Centrosome Centrioles Golgi apparatus Peroxisome Microtubule Secretory vesicles Cilia Microvilli

Fig. 3.16 Outer membrane of nuclear envelope Ribosomes Nucleus Copyright © McGraw-Hill Education. Permission required for reproduction or display. Outer membrane of nuclear envelope Ribosomes Nucleus Nuclear pore Nucleus Rough endoplasmic reticulum Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosome TEM 30,000x (a) (b) b: ©J. David Robertson, from Charles Flickinger, Medical Cell Biology, Philadelphia

b: ©Biophoto Associates/Science Source Fig. 3.17 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Secretory vesicle Golgi apparatus Secretory vesicles (b) (a) b: ©Biophoto Associates/Science Source

Fig. 3.18 Cell membrane 1 A vesicle forms around material Copyright © McGraw-Hill Education. Permission required for reproduction or display. Cell membrane 1 A vesicle forms around material outside the cell. 1 Vesicle forming 2 The vesicle is pinched off from the cell membrane and becomes a separate vesicle inside the cell. 2 Golgi apparatus Fusion of vesicle with lysosome 3 A lysosome is pinched off the Golgi apparatus. 3 4 4 The lysosome fuses with the vesicle. Lysosome 5 The enzymes from the lysosome mix with the material in the vesicle, and the enzymes digest the material. 5

b: ©EM Research Services, Newcastle University RF Fig. 3.19 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Outer membrane Intermembrane space Inner membrane Matrix DNA Longitudinal section Crista Cross section Enzymes (a) (b) TEM 34,000x b: ©EM Research Services, Newcastle University RF

Fig. 3.1 Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Copyright © McGraw-Hill Education. Permission required for reproduction or display. Cell membrane Cytoplasm Nuclear envelope Nucleus Nucleolus Mitochondrion Ribosome Lysosome Free ribosome Lysosome fusing with incoming phagocytic vesicle Rough endoplasmic reticulum Smooth endoplasmic reticulum Phagocytic vesicle Centrosome Centrioles Golgi apparatus Peroxisome Microtubule Secretory vesicles Cilia Microvilli

Fig. 3.22 1 DNA contains the information necessary to Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 DNA contains the information necessary to produce proteins. Nucleolus DNA strand 1 2 Transcription of one DNA strand results in mRNA, which is a complementary copy of the information in the DNA strand needed to make a protein. mRNA strand 2 Nucleus Transcription Cytoplasm 3 The mRNA leaves the nucleus and goes to a ribosome. 3 Arginine 4 Amino acids, the building blocks of proteins, are carried to the ribosome by tRNAs. U tRNA C G 5 5 In the process of translation, the information contained in mRNA is used to determine the number, kinds, and arrangement of amino acids in the polypeptide chain. T r anslation Arginine Aspartic acid Amino acid pool 4 mRNA strand U C A G G A C U U C Polypeptide chain A G Ribosome

Fig. 2.16 Copyright © McGraw-Hill Education. Permission required for reproduction or display. (a) Two examples of amino acids. Each amino acid has an amine group (—NH2) and a carboxyl group (—COOH). H CH3 H H Amino acid (alanine) H N C C OH H N C C OH Amino acid (glycine) H O H O H2O (b) The individual amino acids are joined. H CH3 H H H N C C N C C OH H O H O H H N HO O (c) A protein consists of a chain of different amino acids (represented by different- colored spheres). C C C H N C O H C C O H N C N C C C H H O (d) A three-dimensional representation of the amino acid chain shows the hydrogen bonds (dotted red lines) between different amino acids. The hydrogen bonds cause the amino acid chain to become folded or coiled. N H O C C N C C N O C N H C O O C C H C H N C O N H C C N C O H N O O C C C H H C N H O C N C C N C O O C N H H O C C C N H H N C O C O C N Folded C O H N Coiled O C C (e) An entire protein has a complex three-dimensional shape.

b: ©Don Fawcett/Science Source Fig. 3.20 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Nucleus Cell membrane Mitochondrion Protein subunits Ribosomes 5 nm 25 nm Endoplasmic reticulum Microtubules Protein subunits 10 nm SEM 60,000x Intermediate filaments Protein subunits (b) 8 nm (a) Microfilaments b: ©Don Fawcett/Science Source

Molecule A Molecule B Enzyme New molecule AB Fig. 2.18 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Molecule A Molecule B Enzyme New molecule AB

Fig. 3.14 Chromatin Chromosome Proteins DNA Copyright © McGraw-Hill Education. Permission required for reproduction or display. Chromatin Chromosome Proteins DNA

Fig. 3.22 1 DNA contains the information necessary to Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 DNA contains the information necessary to produce proteins. Nucleolus DNA strand 1 2 Transcription of one DNA strand results in mRNA, which is a complementary copy of the information in the DNA strand needed to make a protein. mRNA strand 2 Nucleus Transcription Cytoplasm 3 The mRNA leaves the nucleus and goes to a ribosome. 3 Arginine 4 Amino acids, the building blocks of proteins, are carried to the ribosome by tRNAs. U tRNA C G 5 5 In the process of translation, the information contained in mRNA is used to determine the number, kinds, and arrangement of amino acids in the polypeptide chain. T r anslation Arginine Aspartic acid Amino acid pool 4 mRNA strand U C A G G A C U U C Polypeptide chain A G Ribosome

REACTANT PRODUCTS ATP ADP + Pi + Energy More potential energy Fig. 2.8 Copyright © McGraw-Hill Education. Permission required for reproduction or display. REACTANT PRODUCTS ATP ADP + Pi + Energy More potential energy Less potential energy (a) REACTANTS PRODUCT ADP + Pi + Energy ATP Less potential energy More potential energy (b)

(all): ©Ed Reschke/Photolibrary/Getty Images Fig. 3.26 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Nucleus 1 Interphase is the time between cell divisions. DNA is found as thin threads of chromatin in the nucleus. DNA replication occurs during interphase. Chromatin Centriole 2 In prophase, the chromatin condenses into chromosomes. Each chromosome consists of two chromatids joined at the centromere. The centrioles move to the opposite ends of the cell, and the nucleolus and the nuclear envelope disappear. Centromere Chromatid Chromosome Chromatid 3 In metaphase, the chromosomes align in the center of the cell in association with the spindle fibers. Spindle fiber Chromosomes 4 In anaphase, the chromatids separate to form two sets of identical chromosomes. The chromosomes, assisted by the spindle fibers, move toward the centrioles at each end of the cell. The cytoplasm begins to divide. Identical chromosomes 5 In telophase, the chromosomes disperse, the nuclear envelopes and the nucleoli form, and the cytoplasm continues to divide to form two cells. Nucleoli Nuclear envelope 6 Mitosis is complete, and a new interphase begins. The chromosomes have unraveled to become chromatin. Cell division has produced two daughter cells, each with DNA that is identical to the DNA of the parent cell. (all): ©Ed Reschke/Photolibrary/Getty Images

b: ©Don W. Fawcett/Science Source Fig. 3.2 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Membrane channel Receptor molecule Carbohydrate chains Nonpolar regions of phospholipid molecules External membrane surface Polar regions of phospholipid molecules Phospholipid bilayer Cholesterol Internal membrane surface Cytoskeleton (a) 15 nm (b) TEM 1,000,000x b: ©Don W. Fawcett/Science Source

Specific Non-lipid-soluble non-lipid-soluble molecules Fig. 3.4 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Specific non-lipid-soluble molecules or ions Non-lipid-soluble molecules Lipid-soluble molecules Membrane channel Concentration gradient

Na+ K+ leak channel (always open) K+ Gated Na+ channel (closed) Fig. 3.5 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Na+ K+ leak channel (always open) K+ Gated Na+ channel (closed) Gated Na+ channel (open)

Fig. 3.3 Distilled water 1 When a salt crystal (green) is placed Copyright © McGraw-Hill Education. Permission required for reproduction or display. Distilled water 1 When a salt crystal (green) is placed into a beaker of water, a concentration gradient exists between the salt from the salt crystal and the water that surrounds it. 2 Salt ions (green) move down their concentration gradient into the water. 3 Salt ions and water molecules are distributed evenly throughout the solution. Even though the salt ions and water molecules continue to move randomly, an equilibrium exists, and no net movement occurs because no concentration gradient exists.

The carrier molecule binds with a molecule, such as glucose, Fig. 3.8 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Glucose 1 Carrier molecule Concentration gradient 1 The carrier molecule binds with a molecule, such as glucose, on the outside of the cell membrane. 2 2 The carrier molecule changes shape and releases the molecule on the inside of the cell membrane.

A Na+–K+ pump maintains a concentration of Na+ that is higher outside Fig. 3.10 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Carrier molecule Na+–K+ pump Na+ 2 Glucose 1 K+ Na+ Glucose 1 A Na+–K+ pump maintains a concentration of Na+ that is higher outside the cell than inside. 2 Na+ move back into the cell by a carrier molecule that also moves glucose. The concentration gradient for Na+ provides the energy required to move glucose, by cotransport, against its concentration gradient.

Fig. 3.9 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Na+– K+ pump 1 Three sodium ions (Na+) and adenosine triphosphate (ATP) bind to the sodium–potassium (Na+– K+) pump. Na+ ATP 1 Na+– K+ pump changes shape (requires energy). Na+ K+ 2 The ATP breaks down to adenosine diphosphate (ADP) and a phosphate (P) and releases energy. That energy is used to power the shape change in the Na+– K+ pump. P 2 ADP 3 The Na+– K+ pump changes shape, and the Na+ are transported across the membrane and into the extracellular fluid. 3 Na+ K+ 4 4 Two potassium ions (K+) bind to the Na+– K+ pump. 5 5 The phosphate is released from the Na+– K+ pump binding site. P Na+– K+ pump resumes original shape. 6 The Na+– K+ pump changes shape, transporting K+ across the membrane and into the cytoplasm. The Na+– K+ pump can again bind to Na+ and ATP. 6 K+

the cell surface bind to molecules to be taken into the cell. Fig. 3.11 Copyright © McGraw-Hill Education. Permission required for reproduction or display. Molecules to be transported Receptor molecules 1 1 Receptor molecules on the cell surface bind to molecules to be taken into the cell. Cell membrane 2 The receptors and the bound molecules are taken into the cell as a vesicle is formed. 2 Vesicle 3 The vesicle membrane fuses and the vesicle separates from the cell membrane. 3

b: ©Don Fawcett/Science Source Fig. 3.12 Copyright © McGraw-Hill Education. Permission required for reproduction or display. 1 A secretory vesicle formed at the Golgi apparatus moves toward the cell membrane. Cell membrane 1 Secretory vesicle Vesicle contents 2 The secretory vesicle membrane fuses with the cell membrane. 2 Secretory vesicle fused to cell membrane Released contents of secretory vesicle 3 The secretory vesicle’s contents are released into the extracellular fluid. 3 TEM 30,000x (a) (b) b: ©Don Fawcett/Science Source

Table 3.2