Chapter 7: Cell Structure and Function I. Life is Cellular • What is a cell? -- A cell is the smallest unit of life that carries out all the functions of a living thing ______________ → Tissues → Organs → (Organ) Systems → Individuals (_____________________________) A. Living things may be either unicellular (like bacteria) or multicellular (humans) B. Cells vary in _____________________________ (shape is related to function) C. The average human is composed of approximately ________________ trillion cells D. There are at least _________________ different kinds of cells in the human body



The Discovery of the Cell A. Invention of _____________________________ was an essential breakthrough in biology B. In 1665 Robert _____________________________ published illustrations of observations using a microscope 1. Hooke coined term “_____________________________” after observing dead cork cells C. Early 1670's Anton van _____________________________ observed pond water & blood (first to observe living cells) People of the Cell Theory A. Matthias _____________________________ concluded all plants are made of cells B. 1839 Theodor Schwann concluded all living things are made of cells C. 1855 Rudolf Virchow infers that all ______________________ cells come from _____________________________ cells Cell Theory: 1. Cells are the basic units of all life (all things are composed of cells) 2. All organisms are made of one or more cells (cells are the basic units of _____________________________ and _____________________________ in living things) 3. All cells _____________________________ from existing cells

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Two Kinds of Cells 1. _____________________________: Cells with _______ membrane bound nucleus or organelles Example: bacteria 2. _____________________________: Cells ________________ _____________________________ bound nucleus and organelles Example: plant and animal cells

II. Cell Structure Cell Organization A. The Cytoplasm A _____________________________ substance_____________________________the cell, surrounding the nucleus. Everything inside the cell that is not the nucleus or organelles. - _____________________________ are structures within the cell that perform individual and specific _____________________________ 1. _____________________________: A network of microfilaments and microtubules extending throughout the cytoplasm. Functions: a. _____________________________ and give _____________________________ b. anchor organelles c. in some cells allows cells to _____________________________ B. The Nucleus 1. Nucleus: _____________________________ _____________________________of the cell. Holds most of the _____________________________ material a. Nuclei are surrounded by a double membrane - the nuclear _____________________________ i. Nuclear envelope has pores that allow proteins & RNA to pass through b. _____________________________: Structures made out of nucleic acids that carries the _____________________________ _____________________________for the organism Definite number of chromosomes per organism Example: Humans have 23 pair or _________ total i. Chromatin: _____________________________ of nucleic acid wrapped around protein “spools” c. _____________________________: Small, organelle located inside of the nucleus that produces ribosomes (ribosomes manufacture proteins for the cell)



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The Organelles 1. _____________________________: Contain digestive enzymes that help _____________________________ ____________________large molecules of carbohydrates, proteins, and lipids for the cell



a. Also used to digest old organelles b. If lysosomes break apart it means certain death for cells (certain types of arthritis) 2. Ribosomes: Make _____________________________ (out of amino acids) a. Found free _____________________________ or bound to membranes b. Found in eukaryotic and prokaryotic cells (only organelle found in _____________________________) c. Ribosomes do not have a membrane like other organelles 3.. Endoplasmic Reticulum (_____________): An extensive network of membranes that produces materials for the cell Two Types of ER 1. Rough ER -- _____________________________ due to _____________________________ of ribosomes on the outside of the ER -- Helps synthesize proteins & manufacture new cell membrane 2. Smooth ER -- Smooth due to _____________________________ of ribosomes -- _____________________________ in making lipids, processes carbohydrates, and modifies chemicals toxic to the cell 4. _____________________________ Apparatus: Prepares large molecules for _____________________________ in the cell or for secretion out of the cell a. Structure- Series of flat, membrane-bound _______________ 5. _____________________________: Provides most of the _____________________________ needed for the cell a. Creates adenosine triphosphate (__________), which is the energy currency for the cell b. Double-membrane bound organelle that has a ____________ inner membrane c. Also found in parts of plants



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Cellular Boundaries Cell Membrane (aka _____________________________ Membrane) 1. A thin layer of _____________________________ & _____________________________ that separates the cell’s contents from its environment 2. 10,000 membranes ~ thickness of a sheet of paper





3. Membranes are made of _____________________________ a. a phospholipid consists of a _____________________________ head with ______ _____________________________ _____________________________ chains b. phosphate head is hydro_____________________________ or “water- _____________________________” c. lipid tails are hydro_____________________________ or “water-fearing” d. in water, phospholipids form two layers called a lipid _____________________________

Structures for Movement Two types of structures are extensions of cytoskeleton that aid in movement 1. Cilia: Short, _____________________________ projections usually present in large numbers (Ex: Ciliates or small unicellular eukaryotes; human tracheal cells) 2. _____________________________: Long, tail-like structures that function like a whip or _____________________________ --Cells usually have only one or two flagella Cell Diversity



A. Differences between plant and animal cells i. Plants have _____________________________ _____________________________ - Adds support outside of cell membrane ii. Plants have specialized organelles -Chloroplasts-centers of photosynthesis -Large _____________________________ _____________________________: stores water for photosynthesis



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III. Cell Transport A. ____________permeable membrane: only allows certain substances to pass through B. _____________________________ Transport: _______ _____________________________ required for movement through the membrane 1. Diffusion: Movement from area of ________________ to _____________ concentration a. Facilitated: Requires help (carrier protein) b. _____________________________: ___________________________ distributed throughout 2. _____________________________: Movement of _____________________________ across a semipermeable membrane a. _________________________tonic: ______________________ Solute Concentration

b. ________________________tonic: _______________________ Solute Concentration



c. _____________tonic: _____________________________ concentrations of solute

C. Active Transport: Requires the use of energy (ATP) 1. _______________cytosis: Movement from _____________________________ to _____________________________ of cell (packaged in Golgi) 2. _________________cytosis: Movement from _____________________________ to inside of cell - _______________cytosis: Cell _____________________________, intake of water - _________________cytosis: Cell ____________________________ or engulfing (Ex. WBC)



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