BIO 101 Life Science Unit 1 Cells Chapter

BIO 101: Life Science Unit 1: Cells Chapter 4. A Tour of the Cell Instructor: Dr. Li Lu Office: CH 208 C Email: li. lu@kysu. edu

Outline Cell Theory Eukaryotic and Prokaryotic Cells Cellular Structures and Components

Ø Robert Hooke designed the first microscope and discovered the existence of cells around 1665. Ø Cell is the smallest unit that can display all the characteristics of life.

Review: the characteristics of life? Ø Ordered organization with boundaries Ø Carefully regulated internal environment Ø Response to the external environment Ø Growth and development Ø Reproduction Living cells have all these characteristics. Beating Heart cells under microscope https: //www. youtube. com/watch? v=U 4 A_1 Igh_2 w

Cell Theory § All living organisms are composed of cells and cells form a unifying structural basis of organization. § All cells come from other cells --- only existing cells can give rise to more cells.

Prokaryotes vs. Eukaryotes Life Prokaryotes Eukaryotes Plantae Domain Bacteria Domain Archaea Fungi Animalia Three kingdoms Domain Eukarya Protists (all other eukaryotes)

Eukaryotic cell Prokaryotic cell (bacterium) • Smaller • Simpler structure • DNA concentrated in • Larger • More complex Organelles structure • Nucleus enclosed by membrane nucleoid region, which is not enclosed by membrane • Contains many • Lacks most organelles types of organelles Nucleoid region Colorized TEM Nucleus prokaryotic vs. eukaryotic cells

Ø Prokaryotic cells evolved earlier than eukaryotic cells. v Prokaryotes appeared about 3. 5 billion years ago. v Eukaryotes appeared about 2. 1 billion years ago. Ø What are in common between them: v They are all bounded by a thin cell membrane (or called as plasma membrane). v Inside all cells is a thick, jelly-like fluid called the cytoplasm, in which cellular components are suspended. “cyto-” : a prefix meaning "cell" v All cells have genetics information stored in genes made by DNA. v All cells have ribosomes, tiny structures that build proteins according to the instructions from the DNA.

ØWhat are different between these two kinds of cells: v. Prokaryotic cells are usually smaller than eukaryotic cells and simpler in structure. v Only eukaryotic cells have membrane-enclosed organelles that perform specific functions. v The most important organelle is the nucleus, which houses most of a eukaryotic cell’s DNA and is surrounded by a double membrane. v A prokaryotic cell lacks organelles and nucleus. Its DNA is coiled into a nucleus-like region called the nucleoid, which is not partitioned from the rest of the cell by membranes.

Overview of Prokaryotic Cells Plasma membrane Prokaryotic flagellum Ribosomes Colorized TEM Nucleoid

Cytoskeleton Ribosomes Not in most plant cells Centriole Lysosome Plasma membrane Idealized animal cell Nucleus Mitochondrion Rough endoplasmic reticulum (ER) Smooth endoplasmic reticulum (ER) Golgi apparatus Cytoskeleton Mitochondrion Central vacuole Cell wall Chloroplast Nucleus Rough endoplasmic reticulum (ER) Ribosomes Not in animal cells Idealized plant cell Plasma membrane Smooth endoplasmic reticulum (ER) Channels between cells Golgi apparatus

Overview of Eukaryotic Cells ØCell Wall: outside of cell membrane, not exist in animal cells. ØPlasma membrane: boundary of living cells. ØCytoplasm: consists of all cellular components between the plasma membrane and the nucleus. ØNucleus: stores genetic information (DNA). ØCytosol - Fluid within cytoplasm. ØOrganelles - Persistent structures of various shapes and sizes with specialized functions --Most, but not all, are bound by membranes.

Figure 4. 5 b Cell Surfaces Ø Plant cells have rigid cell walls surrounding the membrane. Ø Plant cell walls: • are made of cellulose what is that? (“-ose” means it is a kind of carbohydrate we talked in Chapter 3) • protect the cells, maintain cell shape, and keep cells from absorbing too much water. Cell wall (Animal cells lack cell walls)

Membrane Structure: Plasma Membrane: the semipermeable outer boundary of the living part of the cell --- necessary for all living cells! Plant cells have cell membrane as well as cell wall! Plasma membrane

Membrane Structure: Plasma Membrane: the semipermeable outer boundary of the living part of the cell. Outside of cell Hydrophilic head Hydrophobic tail Cytoplasm (inside of cell) model of membrane • Regulates movement of substances into and out of cell, • Composed of phospholipids Phospholipid (phospho-lipid) arranged in bilayer two layers---the phospholipid bilayer, with proteins interspersed throughout, why lipids and proteins are important to living organisms? Proteins

Membrane Structure: Plasma Membrane: the semipermeable outer boundary of the living part of the cell. Outside of cell Hydrophilic head Hydrophobic tail Proteins • Support all the following characteristics of cell/life: Phospholipid bilayer Ø Ordered organization with boundaries Ø Carefully regulated internal environment Cytoplasm (inside of cell) Fluid mosaic model of membrane Ø Response to the external environment

Nucleus: 1. contains DNA, 2. is the control center of cell. nucleus

Nucleus: 1. contains DNA, 2. is the control center of cell. Bound by nuclear envelope (or called as nuclear membrane) with numerous nuclear pores, which are “gates” for exchange of materials. Chromatin Nuclear Ribosomes fiber envelope Nucleolus Nuclear pore : Permit only certain kinds of molecules to pass between nucleus and cytoplasm.

v v Nucleolus (plural nucleoli) : “darker” region in the nucleus, the synthesis site of ribosome subunits (RNA and protein). Chromatin fiber: – Composed of DNA and proteins – Coil and become chromosomes Chromatin Nuclear Ribosomes fiber envelope Nucleolus Nuclear pore –The number of chromosomes in a cell depends on the species.

DNA molecule Review: The relationship between DNA, chromatin, and a chromosome. Chromatin fiber Proteins Chromosome

Ribosomes – the small dots colored as blue in the figure below. Responsible for protein synthesis. Ribosomes

DNA How DNA Directs Protein Production Step 1: transcription (DNA m. RNA) Step 2: transportation of m. RNA from nucleus to cytoplasm Step 3: translation (m. RNA protein) More details in Chapter 10 1 Synthesis of m. RNA in the nucleus m. RNA Nucleus Cytoplasm 2 Movement of m. RNA into cytoplasm via nuclear pore m. RNA Ribosome 3 Synthesis of protein in the cytoplasm Protein

The Endomembrane System: v Many membranous organelles form an interconnected membrane system inside (endo-) the cell. v Including: plasma membrane (for some books); nuclear envelope; Endoplasmic Reticulum; Golgi apparatus; lysosomes; vacuoles; and floating vesicles. v. Manufacturing and distributing cellular products

Endoplasmic reticulum: a membrane network of flattened sacs and tubes throughout the cytoplasm. Two parallel membranes with a narrow space between them. Endoplasmic reticulum (ER)

Endoplasmic reticulum: a membrane network of flattened sacs and tubes throughout the cytoplasm. Two parallel membranes with a narrow space between them. Nuclear envelope Ribosomes Smooth ER TEM Rough ER Ribosomes Rough ER: Communication and transportation of materials, generally proteins. Smooth ER: Synthesis of more membrane lipids.

Rough ER - ribosomes on outer surface of ER (“rough” surface) ---Supports protein synthesis and storage. Secretory proteins depart. Vesicles bud off from the ER. Proteins are modified in the ER. Transport vesicle Ribosome A ribosome links amino acids. Protein Polypeptide Rough ER How rough ER modifies and packages proteins.

smooth ER: • connects with rough ER, • lacks surface ribosomes (“smooth” surface), • produces lipids and membranes.

The Golgi apparatus: Stacks of flattened, disk-like sacs. Golgi apparatus Special looks: “a stack of pita bread”

The Golgi apparatus: Stacks of flattened, disk-like sacs. works in partnership with the ER, receives, refines, stores, and distributes chemical products of the cell, has poles: “receiving side” and “shipping side”. “Receiving” side of the Golgi apparatus Transport vesicle from rough ER 1 “Receiving” side of the Golgi apparatus New vesicle forming Colorized SEM 2 New vesicle forming 3 “Shipping” side of the Golgi apparatus Plasma membrane Transport vesicle from the Golgi apparatus

§ Lysosome: the “digestive” organelle found in animal cells, must be membrane-bound. Lysosomes

A lysosome is a membrane-bound sac of digestive enzymes found in animal cells. Lysosomes are absent from most plant cells. Enzymes are special proteins to speed up chemical reactions. Enzymes in a lysosome can break down large molecules such as • proteins, • polysaccharides, • fats, and • nucleic acids.

Vacuoles: large membrane-bound sacs. Ø Generally exist in plant cells and protists. Ø Not in animal cells. Vacuole in plant cell model

Vacuoles: large membrane-bound sacs. • store organic nutrients, • absorb water, and • may contain pigments or poisons (for defense). Central vacuoles of plants

Rough ER Golgi apparatus Transport vesicles carry enzymes and other proteins from the rough ER to the Golgi for processing. Plasma membrane Lysosomes carrying digestive enzymes can fuse with other vesicles. Secretory protein Some products are secreted from the cell. Vacuoles store some cell products. Review of the endomembrane system

Chloroplasts and Mitochondria: energy conversion Cells require a continuous energy supply to perform the work of life. Two organelles participate in energy conversion: 1. chloroplasts 2. mitochondria.

Chloroplasts Most of the living world runs on the energy provided by photosynthesis. Photosynthesis is the conversion of light energy from the sun to the chemical energy of sugar and other organic molecules. Chloroplasts are unique to the photosynthetic cells of plants and algae and the organelles that perform photosynthesis.

Chloroplast: the organelle that performs photosynthesis, is bound by double membranes, and has stacks of disc-like membrane sacs inside. It has true color (generally green, sometimes golden-green or brownish-green). “chloro-”: a prefix meaning “green” Chloroplasts in plant cell model

Chloroplast: the organelle that performs photosynthesis, is bound by double membranes, and has stacks of disc-like membrane sacs inside. It has true color (generally green, sometimes golden-green or brownish-green). “chloro-”: a prefix meaning “green” Chloroplasts in plant cell model

Chloroplasts: bound by double membranes and contain: Ø Grana (singular, granum): stacks of disk-like membrane system; • contain chlorophyll: responsible for the green color. Granum TEM Ø Stroma: the liquid in between. Inner and outer membranes

Mitochondria: site of cellular respiration, a process of releasing energy from organic molecules and synthesize ATP molecules (more details later). Mitochondria are found in almost all eukaryotic cells (plant cells have mitochondria also!!!). You can regard mitochondria as the “power factory” for cells and organisms.

Mitochondria: the organelles for cellular respiration, are bound by two layers of membranes, and have a lot of folds on the inner membrane. mitochondria in animal cell model

Mitochondria are bound by two layers of membranes. Outer membrane Inner membrane Cristae TEM • Cristae: the numerous folds of inner membrane. • Matrix: the space within the inner membrane.

Ø Cytoskeleton: “cyto-skeleton”, a network of fibers extending throughout the cytoplasm. cytoskeleton fibers in animal cell model

Figure 4. 21 LM Ø The cytoskeleton: • provides mechanical support to the cell; • helps a cell or part of the cell to move; • provides anchorage and reinforcement for many organelles. Ø The cytoskeleton contains fibers made from different proteins. (a) Fluorescent images of cytoskeleton

Ø Changes in the cytoskeleton contribute to the amoeboid (crawling) movements of • protist Amoeba • some of our white blood cells Video of Crawling Amoeba: http: //www. dnatube. com/vide o/4163/Crawling-Amoeba (b) Crawling movement achieved by cytoskeleton

Ø Cilia and flagella are extensions of cytoskeleton that aid in cellular movement. Ø They have the same basic architecture, but cilia are generally shorter and more numerous than flagella. Ø Cilia may extend from nonmoving cells also. On cells lining the human trachea, cilia help sweep mucus with trapped debris out of the lungs.

Colorized SEM Colorize SEM (a) Flagellum of a human sperm cell (b) Cilia on a protist (c) Cilia lining the respiratory tract

Movement of salmon sperms by flagellum

Movement of cilia on the surface of Paramecium

Summary: Eukaryotic vs. Prokaryotic Cells CATEGORIES OF CELLS Prokaryotic Cells Eukaryotic Cells • Smaller • Larger • Simpler • Most do not have organelles • Found in bacteria and archaea • More complex • Have organelles • Found in protists, plants, fungi, animals

Eukaryotic vs. Prokaryotic Cells

Summary: can you label the cellular structures in a photo or model? The major cellular components: 1. Membrane system: Plasma membrane --- no problem! ER --- rough vs. smooth, irregular sacs Golgi apparatus --- very special shape, you can regard it as a stack of disks, or a stack of pita bread. Central vacuole --- big sacs! Only in plants! 2. Organelles: Nucleus --- big, round, sometimes you can see chromatin fibers and nucleolus Ribosomes --- small! Numerous! On rough ER or in cytoplasm Lysosome --- medium size, round Chloroplasts --- big, special green color! Complicated inner membrane system looks like stacks of disks, only in plants! Mitochondrion --- big! Complicated inner membrane system with a lot of folds on the inner membrane! In every eukaryotic cell!

Idealized animal cell

Ribosomes Cytoskeleton Lysosome (not in most plant cells) Plasma membrane Cytoplasm /cytosol Nucleus Mitochondrion Rough endoplasmic reticulum (ER) Golgi apparatus Smooth endoplasmic reticulum (ER) Idealized animal cell

Idealized plant cell

Cytoskeleton Central vacuole Mitochondrion Cell wall Chloroplast Nucleus Rough endoplasmic reticulum (ER) Ribosomes Plasma membrane Smooth endoplasmic reticulum (ER) Cytoplasm /cytosol Golgi apparatus Idealized plant cell Not in animal cells

For all these cellular components, after you know what they look like, you need to know what they can do for the cell, for the organism, or even for the whole ecosystem.

Higher Plant Cells Versus Animal Cells Plants have these additional structures: Cell walls Chloroplasts Central Vacuoles Animals: Have Internal or external skeletons No cell walls No chloroplasts or vacuoles

Expected Learning Outcomes: Chapter 4 is another important chapter that requires a lot of details being fully understood and remembered. 1. Fully understand Cell Theory (slide 5). 2. Be able to list the similarities and differences between Eukaryotic and Prokaryotic Cells in details (slides 8, 9, 50, and 51). 3. Be able to list/label all the major cellular structures/organelles, and know their characteristics and functions in details (need to study the whole chapter, there additional practices on slides 53 and 55). 4. Be able to list the similarities and differences between Plant Cells and Animal Cells (differences are summarized in slide 58).

Suggested reading after the class: Chapter 4 is quite important with the details of cell, which is the basic unit of life. I suggest you to read the whole chapter. Also look at self-quiz questions 1, 3, 6, and 7. There are two video provided by Pearson about animal and plant cells respectively, I have loaded them onto Blackboard Course Documents. Also there is a very helpful You. Tube video: http: //www. youtube. com/watch? v=m. UJry. LNKScg

Assignment 1 C: 1. Label the following THREE pictures, and explain the characteristics/functions of each structure (labeling: 7 points; characteristics/functions: 10 points). 2. Summarize the differences between prokaryotic cells and eukaryotic cells (list at least three differences, 3 points). Requirement: 1. Submit through Blackboard. You can do the labeling by list the number of the structure first, and then its name and functions. 2. Plagiarism will not be tolerated. 3. Twenty points. Due day is posted on Blackboard, but I strongly suggest you to begin AS EARLY AS YOU CAN.

Assignment 1 C Question 1 labeling work 1 1. 3. 2.

Format of the answers for Question 1: Labeling work 1 #1. name, function, #2. name, function, #3. name, function. Labeling work 2 #1. name, function, #2. name, function, #3. name, function. ……

Assignment 1 C Question 1 labeling work 2 3. 4. 2. 5. 1. 6. 8. 7.

Assignment 1 C Question 1 labeling work 3 5. 4. 6. 3. 2. 1. 7. 8.