Cellular Structure and Function Chapter 7 Cellular Structure and Function

The Cell Theory All organisms are composed of one or more cells The cell is the basic unit of structure and organization of organisms. All cells come from preexisting cells.

Advent of the Cell Hooke and Leeuwenhoek used early microscopes Hooke saw/named “cells” in dead cork Leeuwenhoek saw living cells in pond water

Light Microscopes Use 1 or more lenses and visible light Can view live specimens Max 2000x due to poor resolution

Electron Microscopes Uses electrons instead of light for image Very high power/resolution ( max 2 million X) Specimen prep is deadly SEM = Scanning, 3d surface image TEM = Transmission, 2d, more powerful, view slice Microscopy Links http://biologygmh.com/ 9560x

Cell Types Prokaryotes Eukaryotes Simple (small) More complex (larger) Plasma membrane Cytosol Non-membrane bound organelles No membrane bound organelles More complex (larger) Plasma membrane Cytosol Non-membrane bound organelles Has membrane bound organelles Nucleus

Plasma Membrane Cell boundary (inside vs. environment) Phospholipid Bilayer Selectively permeable Controls what/how much can enter or leave cell Allows waste out/nutrients in

Phospholipid Bilayer Phospholipid structure 2 layers, tails facing each other Glycerol + phosphate polar “Head” 2 nonpolar fatty acid tails (sat or unsat)

The Fluid Mosaic Model Phospholipid flow Other molecules float on/with lipids Proteins Carbs Cholesterol

Membrane Proteins Signal transmission Transport Support

Membrane Carbohydrates Attached to protein or lipid Convey signals/communication

Membrane Cholesterol Embedded into phospholipids Increase membrane fluidity Especially in low/high heat Unsat fat also helps with low temp

Cell Structures and Organelles Animal Cell Plant Cell Cellular Pursuit

7.3 Structures and Organelles

7.3 Structures and Organelles

Outer Cell Structures Cell Membrane Cell Wall All cells have it Flexible Phospholipid bilayer w/proteins Selectively permeable (controls in/out) Cell Wall Not found in animal cells Inflexible barrier for cell protection and support

Outer Structures Cont. Flagella Cilia Long whiplike projections on some cells Used for movement or feeding Cilia Small numerous cell projections on some cells

Some other major structures Nucleus Enclosed by double membrane nuclear envelope Envelope has pores for transport Contains DNA and nucleoli Ribosomes Protein synthesis Made by nucleoli No membrane (all cells have them)

Energy Organelles Mitochondria Chloroplast In all eukaryotic cells Site of cell respiration (ATP production, Energy!) Has folded inner membrane Chloroplast Only in Plant/algae cells Site of photosynthesis (organic molecule creation) Has lots of small sacs stacked inside

A Cell Framework Cytoskeleton Centrosome/Centrioles Protein skeleton Provides structure, support, transport Centrosome/Centrioles microtubule production (ex. cell reproduction) Centrioles only in animal cells

Endomembrane System Endoplasmic Reticulum (ER) Golgi Apparatus Highly folded membranes Smooth ER: lipid synthesis Rough ER (w/ribosomes): protein synthesis Transport and detox Golgi Apparatus Flattened stack of membranes Modifies, packages, export proteins

Endomembrane System II Vacuoles Membrane bound storage vesicles Reduced or not present in animal cells Very large central vacuole in plants Lysosomes Membrane bound digestive vesicle Contain enzymes Usually only in animal cells

Cellular Transport Passive Transport (uses no Energy) Diffusion Osmosis Facilitated Diffusion

Diffusion Move from high to low conc. “Down” the conc. Gradient Affected by temp, pressure, conc. Dynamic Equilibrium = no net movement Initial Conditions Diffusion Low High High Low

Osmosis Diffusion of water across membrane Water is bound by solutes More solute = less water Water moves from low solute to high solute Solutes suck

Osmosis II Three osmotic conditions Isotonic: equal solute/water, no net movement Hypertonic: more solute (water enters) Hypotonic: less solute (water leaves) Pay attention to frame of reference Ex. The aquarium fish cells are hypertonic to the water can also be the aquarium water is hypotonic to the fish cells

Osmosis III You find yourself stranded in a ship at sea. There is no rescue in sight, and you’ve already eaten Ra (2 hours after being stranded). Should you drink the seawater or go without water? The zombie invasion has begun. You avoid Luckee (smart move, even if she’s not a zombie) by ducking into a bathroom. Is it a good idea to sleep in the bathtub full of water (assuming you won’t drown)?

Facilitated Diffusion Diffusion through a membrane protein Effects molecules unable to pass through membrane without help: Larger and polar Charged (ions)

Diffusion in a Cell

Channel Proteins Carrier Proteins

Active Transport All move from low to high conc. All use Energy (ATP) 3 types: Protein pumps Endocytosis Exocytosis

Sodium Potassium Pump Sample protein pump Pumps 3 Na+ out of cell; 2 K+ into cell Uses ATP, makes electrochemical gradient Gradient of charge and chemicals

Endo/Exocytosis Endocytosis: Exocytosis Ingest large molecules or small cells Envelope particles with cell membrane Exocytosis Release large molecules/waste Merge vesicle with cell membrane

7.1 Formative Questions Robert Hooke and Anton van Leeuwenhoek designed microscopes that enabled them to see organelles within the cells they observed. true false A B FQ 1

transmission electron microscope scanning electron microscope 7.1 Formative Questions Which type of electron microscope directs electrons over the surface of a nonliving specimen, producing a three-dimensional image? transmission electron microscope scanning electron microscope scanning tunneling electron microscope atomic force microscope A B C D FQ 2

All cells, whether eukaryotic or prokaryotic, have a plasma membrane. 7.1 Formative Questions All cells, whether eukaryotic or prokaryotic, have a plasma membrane. true false A B FQ 3

What feature of eukaryotic cells has enabled 7.1 Formative Questions What feature of eukaryotic cells has enabled them to develop more specific functions than prokaryotic cells? nucleus organelles genetic material (DNA) larger cell size A B C D FQ 4

Which term describes the function of proteins 7.2 Formative Questions Which term describes the function of proteins found on the outer surface of the plasma membrane? identifiers receptors supporters transporters A B C D FQ 5

Which component of the plasma membrane 7.2 Formative Questions Which component of the plasma membrane contributes to the fluidity of the plasma membrane? phospholipids proteins carbohydrates cholesterol molecules A B C D FQ 6

What is the function of carbohydrates that 7.2 Formative Questions What is the function of carbohydrates that stick out from the outer surface of the plasma membrane? They give the cell shape and enable it to move. They give the plasma membrane fluidity. They help the cell identify chemical signals. They hold the cell in place. A B C D FQ 7

In prokaryotic cells, where does the conversion 7.3 Formative Questions In prokaryotic cells, where does the conversion of fuel particles into usable energy occur? cytoplasm DNA mitochondria ribosomes A B C D FQ 8

Which organelle is similar to the section of a 7.3 Formative Questions Which organelle is similar to the section of a factory that organizes, boxes, and ships the final product? chloroplast endoplasmic reticulum Golgi apparatus mitochondrion A B C D FQ 9

In which structure is light energy captured and 7.3 Formative Questions In which structure is light energy captured and converted to chemical energy? chloroplast lysosome nucleus vacuole A B C D FQ 10

Which type of cellular transport does not require an input of energy? 7.4 Formative Questions Which type of cellular transport does not require an input of energy? active transport endocytosis exocytosis facilitated diffusion A B C D FQ 11

Sugar moves to the right. Water moves to the left. 7.4 Formative Questions How does osmosis occur between the two solutions separated by the selectively permeable membrane? Sugar moves to the left. Sugar moves to the right. Water moves to the left. Water moves to the right. A B C D FQ 12

Which diagram shows a cell in a hypotonic solution? 7.4 Formative Questions Which diagram shows a cell in a hypotonic solution? A. B. C. A B C FQ 13

Compare and contrast plant and animal cells. Chapter 7 Cellular Structure and Function Chapter Assessment Questions Compare and contrast plant and animal cells. Answer: Plant cells have both cell walls and chloroplasts. Animal cells do not have these structures. Only animal cells contain lysosomes. Both plant and animal cells have plasma membranes, a nucleus, mitochondria, vacuoles, endoplasmic reticulum, Golgi apparatus, centrioles, a nucleolus, ribosomes, and a cytoskeleton. CAQ 1

Identify the structure represented by this image. Chapter 7 Cellular Structure and Function Chapter Assessment Questions Identify the structure represented by this image. Answer: plasma membrane and phospholipid bilayer CAQ 2

If you wanted to see a detailed 3-dimensional Chapter Diagnostic Questions If you wanted to see a detailed 3-dimensional image of a cell, which type of microscope would you use? scanning electron microscope transmission electron microscope scanning tunneling microscope simple light microscope A B C D CDQ 1

Which is not a part of the cell theory? Chapter Diagnostic Questions Which is not a part of the cell theory? Cells are the basic unit of structure and organization of all living things. All living things are composed of one or more cells. Cells arise only from previously existing cells. Cells are produced spontaneously as an organism grows. A B C D CDQ 2

Which cell organelles are directly involved with Chapter Diagnostic Questions Which cell organelles are directly involved with the production of proteins? ribosomes, endoplasmic reticulum, nucleus cell membrane, lysosome, Golgi apparatus nucleus, centriole, vacuole endoplasmic reticulum, cilia, mitochondrion A B C D CDQ 3

_______ is the net movement of particles from Chapter Assessment Questions _______ is the net movement of particles from an area where there are many particles of the substance to an area where there are fewer particles of the substance. Diffusion Endocytosis Exocytosis Equilibrium A B C D CAQ 3

What is the magnification of a compound light Standardized Test Practice What is the magnification of a compound light microscope that uses a 10X lens in series with a 25X lens? 2.5X 25X 35X 250X A B C D STP 1

What part of the plasma membrane makes it Standardized Test Practice What part of the plasma membrane makes it difficult for water-soluble substances to move freely into and out of the cell? membrane proteins transport proteins the nonpolar tails in the middle of the plasma membrane the polar heads facing the inside and outside of the cell A B C D STP 2

Muscle cells require a great amount of energy. Standardized Test Practice Muscle cells require a great amount of energy. Which would you expect to find in large numbers in muscle cells? centrioles endoplasmic reticulum mitochondria ribosomes A B C D STP 3

In what type of cell would you most likely Standardized Test Practice In what type of cell would you most likely expect to find numerous lysosomes? a plant cell that stores food, enzymes, or other materials a plant cell that uses light energy for photosynthesis a single-celled organism that moves around its environment a white blood cell that digests bacteria and viruses A B C D STP 4

Standardized Test Practice Why are the carrier proteins that move substances across a plasma membrane from a region of higher concentration to a region of lower concentration called pumps? They require energy to move substances against a concentration gradient. They open and close to allow substances to diffuse across the plasma membrane. They help with the osmosis of water through the plasma membrane. They pump water into the cell, causing the pressure within the cell to increase. A B C D STP 5