Human Biology 175 Lecture Notes: Cells. Section 1 Introduction

Transcription

1 Human Biology 175 Lecture Notes: Cells Section 1 Introduction A) 1) All organisms are composed of at least one cell. a) Unicellular example: b) Multicellular example(s): 2) All cells are similar in their chemical composition. a) Atoms: b) Molecules: (1) (2) (3) (4) c) Cellular structures: (1) (2) (3) 3) All cells are similar in their metabolic activities. a) b) c) 4) All cells arise from pre-existing cells. a) (1) Replace worn out/dead cells (2) Grow-increase cell number b b) 1) Sexual reproduction formation of sex cells (egg and sperm) 5) The cells of any multicellular organism is a result of the activities of its interdependent cells. a) Human body is composed of trillion cells b) These cells can be categorized into >200 different types of tissues Lecture Notes: Cells, Page 1 of 14

2 Section 2 Plasma Membranes A) describes the composition and function(s) of cellular membranes 1) General functions of ALL plasma membranes a) separate b) allow for specific substances to pass from one side to the other (1) semipermeable/selectively permeable/differentially permeable c) Provide a workbench for 2) Composition (molecules that make up animal plasma membranes) a) grout provide structure that holds it together b) tiles / mosaic each protein carries out its own specific function for the membrane c) maintains membrane fluidity d) attached to surface used as recognition/identifying markers and receptors B) structure/grout 1) Consistency of olive oil 2) water-loving a) Water soluble substances b) Chemically interact with water c) Phosphate group (ion) 3) water-fearing a) Insoluble in water b) Move away from water c) Fatty acid tails C) formed when phospholipids are mixed with water 1) 2 layers of phospholipids 2) heads interact with water a) Cytoplasm b) Extracellular fluid (outside) 3) tails sandwiched between D) carry out the functions of a plasma membrane 1) a) Pores b) Porins c) Channels d) Pumps 2) provide a workbench for chemical reactions 3) interact with chemical messengers to turn on/off various cellular activities 4) a) holds cell shape/position b) organelles in specific position 5) a) Identifies a cell (glycoproteins) b) Example: ABO blood group Lecture Notes: Cells, Page 2 of 14

3 Section 3 Diffusion and Osmosis A) the movement of a substance from an area of high concentration to an area of low concentration. 1) energy/heat 2) Continues until evenly distributed throughout reached 3) Molecules that cross plasma membranes by diffusion: a) or lipid soluble b) Examples: (1) (2) B) the movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration. 1) term used to describe the concentration of a solute in one solution as compared to another solution. a) substance that gets dissolved b) substance that does the dissolving c) solution INSIDE the cell d) solution OUTSIDE the cell 2) solution a) Solution that has a higher solute concentration than another solution b) Extracellular solute concentration > cytoplasm solute concentration c) Highest concentration of water is d) Water crosses plasma membrane by e) Water will f) Cell shape: 3) solution a) Solution that has a lower solute concentration than another solution b) Extracellular solute concentration < cytoplasm solute concentration c) Highest concentration of water is d) Water crosses plasma membrane by e) Water will f) Cell shape: Lecture Notes: Cells, Page 3 of 14

4 4) solution a) Solution that has the same solute concentration than another solution b) Extracellular solute concentration = cytoplasm solute concentration c) c) Highest concentration of water is d) Water crosses plasma membrane by e) Water will f) Cell shape: Section 4 Other Membrane Transport Mechanisms A) 1) Shape determines the specific solute s ability to pass through 2) Solute follows the concentration gradient a) Moves from concentration 3) required 4) Examples: a) b) c) B) 1) shape determines the specific solute that can pass 2) Solute is transported its concentration gradient. a) From concentration 3) is required 4) Ex: C) (opposites) 1) Move large volumes of substances in/out of cell 2) (membrane bound sacs) 3) moves substances OUT of cell 4) moves substances INTO cell a) Also called Lecture Notes: Cells, Page 4 of 14

5 Section 5 Organelles A) Review: 1) (usually) a membrane bound sac within the cytoplasm that isolates or compartmentalizes a specific set of chemical reactions. B) Cyto = cell, Plasm jelly-like 1) Includes everything inside of the cell membrane except the nucleus. a) (liquid portion) b) c) 2) Composition a) b) Monomers: c) Macromolecules: d) Energy: 3) Organelles: metabollic machinery 4) areas where chemical substances are stored in some cells a) b) c) d) Lecture Notes: Cells, Page 5 of 14

6 C) 1) (Usually) largest organelle of the human cell 2) Structure: a) b) c) d) 3) Function a) b) c) 4) Nuclear Membrane (nuclear envelope) a) Structure: (1) (2) Proteins: b) Function: 5) (Nondividing cell) a) Structure: (1) (2) Proteins b) Function: 6) a) Structure: (1) (2) (3) Proteins b) Function: D) 1) Structure: a) b) 2) Location: a) b) 3) Function: E) Endoplasmic Reticulum (ER) 1) a) Structure: (1) (2) b) Function: Lecture Notes: Cells, Page 6 of 14

7 2) a) Structure: (1) (2) b) Function: (1) (2) (3) (4) F) 1) Structure: flattened sac of 2) Function: Example: proteins/lipids/mucous/enzymes G) 1) Structure: membrane bound sac filled with 2) Function: molecules within the cell H) 1) Structure: membrane bound sac filled with 2) Function: break down worn out/unusable cellular structures and foreign substances 3) Example: WBCs (phagocytes) I) Cytoskeleton 1) Structure: elaborate network (forms internal framework) 2) Function: a) b) 3) 4) Centrioles a) structure: (Microtubules) b) function: formed during cell division-- 5) sweep substances across a cell surface 6) fingerlike extensions of cell membrane that increase surface area 7) propel sperm J) Cell diversity 1) shape 2) Size 3) Surface extensions 4) Organelles 5) Storage 6) Movements 7) Conductivity 8) Reproduction Lecture Notes: Cells, Page 7 of 14

8 Section 6 Cell Cycle A) Cell cycle: all of the stages a cell will pass through from its formation until it divides. 1) 2) 2 Major periods: a) b) B) Interphase: 1) 90% of a cell s life cycle 2) Normal cellular activities a) b) c) Protein Synthesis d) C) Cell Division: 1) type of nuclear division resulting in genetically identical Cells or 2) division of the D) Mitosis: 1) 1) Disassemble 2) disappear 3) Package chromatin into 4) assemble and 2) a) have migrated to opposite poles b) aligned at the cells equator c) attached to centrioles and chromosomes 3) a) being pulled by the to opposite poles 4) a) REassemble b) REappear c) UNpackage chromsomes into d) DISassemble and 5) Cytokinesis: division of the Lecture Notes: Cells, Page 8 of 14

9 Section 7 DNA Structure A) Watson & Crick s Structure of DNA 1) Structure had to explain: a) b) 2) 3) Each strand is a polymer, a chain of 4) Nucleotides are held together by bonds a) b) sides of the DNA ladder 5) Two strands are held together by bonds a) rungs (steps) of the DNA ladder 6) Two strands are a) Base-Pairing Rules: Purine ::: Pyrimidine b) (double ring): c) (single ring): d) complementary (1) (2) B) the DNA in a NONdividing cell unpackaged/uncondensed 1) Access the N bases (instructions) 1) Protein synthesis 2) DNA replication 2) of the Cell cycle C) the Condensed/packaged DNA in a dividing cell Lecture Notes: Cells, Page 9 of 14

10 Section 8 DNA Replication A) DNA replication is B) Text Description: DNA replication is a process whereby the parent DNA molecule is used as a template to synthesize two daughter DNA molecules. At the end of DNA replication, each DNA (daughter) molecules are composed of one original (parental) strand and one newly synthesized strand of DNA. C) Diagram of DNA Replication 1) a) Enzyme b) Changes the shape of DNA molecule 2) Fee diffuse between strands a) Follow base pairing rules b) Form 3) a) Enzyme makes a polymer of DNA (strand) b) Catalyzes/makes the on the new strand c) base pairing rules Lecture Notes: Cells, Page 10 of 14

11 Section 9 Protein Synthesis A) Central Dogma of Protein Synthesis 1) segment of DNA that codes for a polypeptide 2) Polypeptide: chain of B) 3 types of RNA 1) message RNA Carry genetic code/instructions from the nucleus to the cytoplasm 2) transfer RNA Brings a specific amino acid to the ribosome to make the polypeptide 3) ribosomal RNAOrganelle that builds the polypeptide C) TRANSCRIPTION 1) location: 2) : a segment of DNA that codes for a polypeptide a) One strand b) Code is the sequence of N bases 3) Gene Structure: a) sequence of N bases that RNA polymerase recognizes to initiate/start transcription b) sequence of N bases that identifies the amino acid sequence of the polypeptide/protein c) sequence of N bases that RNA polymerase recognizes as the end of transcription. Lecture Notes: Cells, Page 11 of 14

12 4) Events of Transcription: a) Location: b) (1) Enzyme (2) Recognizes promotor and binds (interacts) with the promotor (3) Accesses the gene on one ONE strand (4) Creates sugar phosphate backbone on mrna molecule (5) Stops when it gets to the terminator c) (1) Diffuse between DNA strands (2) H bond to N bases of DNA (3) Follow base pairing rules (a) (DNA) G (RNA) (b) (DNA) C (RNA (c) (DNA) T (RNA) (d) (DNA) A (RNA) Lecture Notes: Cells, Page 12 of 14

13 D) Translation 1) Location: 2) chain of amino acids 3) Codon Table: used to determine the amino acid sequence of the polypeptide a) triplet of nucleotides that code for a single amino acid (1) Each N base assigned a position 1 st, 2 nd, 3 rd (2) Find each N base on the table and the overlap identifies the amino acid that is determined by the codon. A U G C A A U G C A A C U G A Second Position First Position U C A G Third Position phenylalanine serine tyrosine cysteine U phenylalanine serine tyrosine cysteine C leucine serine stop stop A U leucine serine stop tryptophan G leucine proline histidine arginine U leucine proline histidine arginine C leucine proline glutamine arginine A C leucine proline glutamine arginine G isoleucine threonine asparagine serine U isoleucine threonine asparagine serine C isoleucine threonine lysine arginine A A (start) methionine threonine lysine arginine G valine alanine aspartate glycine U valine alanine aspartate glycine C G valine alanine glutamate glycine A valine alanine glutamate glycine G 61 Lecture Notes: Cells, Page 13 of 14

14 4) (rrna) : organelle that positions the mrna and trna s in order to build the polypeptide in the. a) slides down the mrna reading b) Helps to make between the amino acids 5) trna: bring a specific amino acid to the ribosome-mrna complex a) b) triplet of RNA nucleotides that complements the codon used to identify WHICH amino acid to add next to the polypeptide A U G C A A U G C A A C U G A 6) Codon Table is a) Original DNA code: (1) mrna: (2) Resulting amino acid: b) Original DNA code is changed : (1) Change in the DNA sequence of a gene (2) Mutated DNA (a) mrna: (b) Resulting amino acid: (c) (3) Mutated DNA (a) mrna: (b) Resulting amino acid: (c) (d) Ultimate source of diversity Lecture Notes: Cells, Page 14 of 14