CHAPTER 7: CELLULAR STRUCTURE AND FUNCTION
Section 1: Cell Discovery and Theory
The cell theory states that
1. cells are the unit of structure of all living things
2. cells are the unit of function of living things--they carry out life processes
3. all cells come from pre--existing cells.
Eukaryotic cells contain membrane-bound organelles, including a nucleus. Eukaryotes can be singlecelled or multi-celled, such as you, me, plants, fungi, and insects. Bacteria are an example of
prokaryotes. Prokaryotic cells do not contain a nucleus or any other membrane-bound organelle
7.2 – The Plasma Membrane
Thin, flexible boundary between the cell and its environment
Selective Permeability: Property of the membrane that allows certain materials to pass through the
cell while keeping others out.
Basic Structure of the Plasma Membrane; The plasma membrane is composed of the phospholipid
bilayer. A phospholipid molecule is composed of a glycerol backbone, two fatty acid chains, and a
phosphate group. The polar, phosphate head of a phospholipid molecule is hydrophylic. The nonpolar,
fatty acid tail of a phospholipid molecule is hydrophobic.
Other components include proteins, carbohydrate, and cholesterol.
7.3 Cellular Structure and Function.
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7.4 Cellular Transport
Diffusion: net movement of particles from an area where there are many particles of the substance
(high concentration) to an area where there are few particles of the substance (low concentration)
There are two components of solution:
1. Solvent – a substance in which another substance is dissolved
2. Solute – the substance that is dissolved
Three main factors affect the rate (speed) of diffusion:
1. Concentration of the diffusing particles
2. Temperature
3. Pressure
In facilitated diffusion, special transport proteins move ions and small molecules across the plasma
membrane
Passive transport – movement of a substance across the plasma membrane without the use of the
cell’s energy.
Active transport – requires the use of the cell’s energy to move substances into or out of a cell across
the cell membrane.
Osmosis: The diffusion of water across a selectively permeable membrane.
Isotonic solution: Cell is in a solution that has the same concentration of water and solutes
Hypotonic solution: Cell is in a solution that has a lower concentration of solute than the cell
Hypertonic solution: Cell is in a solution that has a higher concentration of solute than the cell
Endocytosis: Substances too large to move by diffusion or transport proteins get inside through
Endocytosis
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Membrane encloses substance (surrounds it) and then pinches off, leaving it inside the cell
Exocytosis: Exocytosis is the reverse of endocytosis
Cells use it to excrete waste and substances like hormones
Both endocytosis and exocytosis require energy
CHAPTER 8
8.1 Cellular energy
Autotrophs make their own food using energy from the sun. Convert light energy from the sun into
chemical energy.
Heterotrophs need to eat food to obtain energy
Metabolism is all of the chemical reactions in a cell.
ATP: THE UNIT OF CELLULAR ENERGY
Adenosine triphosphate (ATP) is the most important biological molecule that provides chemical
energy
8.2 Photosynthesis
Phase 1 – light dependent reactions – where light energy is absorbed and converted into chemical
energy in the form of ATP and NADPH
Phase 2 – light independent reactions – where the ATP and NADPH that was made in phase one are
used to make glucose.
PHASE 1: Electron transport
Chloroplasts capture light energy in photosynthesis.
Disk-shaped organelles that contain 2 main compartments essential for photosynthesis.
Thylakoids – flattened, saclike membranes that are arranged in stacks called grana
Light dependent reactions take place within the thylakoids.
Stroma are fluid filled spaces outside the grana.
Light independent reactions in phase 2 take place here.
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PHASE 2: THE CALVIN CYCLE
Step 1) Carbon Fixation
-C02 combine with 5-carbon compounds to form 3-PGA (3-phosphoglycerate)
Step 2) Reduction
Energy and phosphate is transferred from ATP and NADPH to the 3PGA molecules to make G3P
(glycerahyde 3-phosphates)
Step 3) Regeneration
An enzyme called Rubisco converts some 3PGA into the 5 carbon compounds used in the beginning
while one of the 3PGA foes to make glucose
8.3 Cellular respiration
Organisms obtain energy by a process called cellular respiration.
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Macromolecules like glucose are broken down to make ATP
ATP is used to provide energy for cells to do work.
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Cellular respiration has 2 parts:
–
Glycolysis
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–
Anaerobic process (does not require oxygen)
Aerobic respiration (Requires oxygen)
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Includes:
–
Krebs Cycle
–
Electron transport
Glycolysis is the process where glucose is broken down in the cytoplasm.
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2 ATP molecules are required to start the reactions.
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Produces:
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2 molecules of ATP and 2 molecules of NADH for each molecule of glucose
that is broken down.
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2 pyruvate molecules
KREBS CYCLE
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The 2 pyruvate molecules are transported to the mitochondria.
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In the mitochondria with the help of oxygen the pyruvate is broken down into:
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6 CO2
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2 ATP
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8 NADH
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2 FADH2
ELECTRON TRANSPORT
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Electron transport is the final step in the breakdown of glucose.
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Electrons move along the mitochondrial membrane from one protein to another.
•
The electron transport produces:
–
•
32 ATP
In eukaryotes one molecule of glucose yields 36 ATPS under ideal conditions.
CHAPTER 9
9.1 Cellular Growth
Transport of Substances:
Substances move by diffusion or by motor proteins.
Diffusion over large distances is slow and inefficient.
Small cells maintain more efficient transport systems.
Cellular Communications:
The need for signaling proteins to move throughout the cell also limits cell size.
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Cell size affects the ability of the cell to communicate instructions for cellular functions.
The Stages of Interphase
The first stage of interphase, G1: The cell is growing, carrying out normal cell functions, and
preparing to replicate DNA.
The Second Stage of Interphase, S: The cell copies its DNA in preparation for cell division.
The Third Stage of Interphase, G2: The cell prepares for the division of its nucleus.
9.3 Cell Cycle Regulation
Different cyclin/CDK combinations signal other activities throughout the cell cycle.
Cancer is the uncontrolled growth and division of cells. Various environmental factors can affect the
occurrence of cancer cells. (carcinogens).
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Apoptosis: Programmed cell death, Cells going through apoptosis actually shrink and shrivel in a
controlled process.
Stem Cells: Unspecialized cells that can develop into specialized cells when under the right conditions
Embryonic Stem Cells: After fertilization, the resulting mass of cells divides repeatedly until there are
about
100–150 cells. These cells have not become specialized.
Adult Stem Cells: Found in various tissues in the body and might be used to maintain and repair the
same kind of tissue
CHAPTER 10 SEXUAL REPRODUCTION
1 Meiosis
Homologous chromosomes—one of two paired chromosomes, one from each parent, Same length,
Same centromere position, Carry genes that control the same inherited traits.
A cell with n chromosomes is called a haploid cell.
A cell that contains 2n chromosomes is called a diploid cell.
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