Module A Review

Hydrogen bonds are responsible for three important properties of water. –High Specific Heat: water resists changes in temp. –Cohesion: water molecules stick to each other. –Adhesion: water molecules stick to other things.

Some compounds form acids or bases. An acid releases a hydrogen ion when it dissolves in water. – high H + concentration – pH less than 7 more acidic stomach acid pH between 1 and 3

A neutral solution has a pH of 7. pure water pH 7

A base removes hydrogen ions from a solution. –low H + concentration –pH greater than 7 bile pH between 8 and 9 more basic

Carbon atoms have unique bonding properties. Carbon forms covalent bonds (strong bonds) with up to four other atoms, including other carbon atoms Carbon-based molecules have three general types of structures – Straight chain – Branched chain (3-D structures) – Ring

Four main types of carbon-based molecules are found in living things. 1.Carbohydrates 2.Lipids 3.Proteins 4.Nucleic acids

Carbohydrates Molecule  Carbohydrates Has Carbon All of the time Has HydrogenAll of the time Has OxygenAll of the time Has Nitrogen - Has Phosphorus - Monomer monosaccharide Polymerdisaccharide (dimer), polysaccharide ExamplesMonosaccharide: glucose, fructose Disaccharide: sucrose (table sugar) Polysaccharide: starch & cellulose (cell wall in plants), glycogen (in animals) Unique-Provide a quick source of energy

Lipids Molecule  Lipids Has CarbonAll of the time Has HydrogenAll of the time Has OxygenAll of the time Has Nitrogen Some of the time Has PhosphorusSome of the time Monomer glycerol & fatty acids; polar heads & fatty acid tails Polymer triglycerides; phospholipids ExamplesFats, oils, cholesterol, steroids, waxes, phospholipids Unique-Nonpolar -Broken down to provide energy -Used to make steroid hormones (control stress, estrogen, testosterone) -Phospholipids make up all cell membranes -Fats and oils contain fatty acids bonded to glycerol Lipids

Proteins Molecule  Proteins Has Carbon All of the time Has HydrogenAll of the time Has OxygenAll of the time Has NitrogenAll of the time Has Phosphorus- MonomerAmino acid PolymerPolypeptide (protein) ExamplesEnzymes, hemoglobin (in blood), muscle movement, collagen Unique-3D structure makes them active -Peptide bonds hold amino acids together -Have a side group (R) that makes each amino acid (and therefore protein) different -Sometimes may contain sulfur

Nucleic acids Molecule  Nucleic acids Has Carbon All of the time Has HydrogenAll of the time Has OxygenAll of the time Has NitrogenAll of the time Has PhosphorusAll of the time Monomer Nucleotide (5-carbon sugar, phosphate group, & base) PolymerNucleic acid ExamplesDNA & RNA Unique - Order of the bases makes every living thing unique -DNA stores genetic information -RNA builds proteins

Dehydration Synthesis Two monomers need to join – One monomer loses (-OH) and one loses (-H) – The two monomers join and the (-OH) and (-H) join, forming H 2 O A-OH + B-H  AB + HOH (H 2 O)

Hydrolysis A polymer needs to break apart (the carbs, proteins, and lipids we ingest are too big for us to use) – Water breaks apart into (-OH) and (-H) and splits the polymer into monomers – The (-OH) and (-H) bond to each monomer to make them stable molecules AB + HOH (H 2 O)  A-OH + B-H

A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions – Decrease activation energy – Increase reaction rate

Enzymes allow chemical reactions to occur under tightly controlled conditions. Enzymes are catalysts in living things. – Enzymes are needed for almost all processes. – Most enzymes are proteins.

Disruptions in homeostasis can prevent enzymes from functioning. Enzymes function best in a small range of conditions. – Changes in temperature or pH can break hydrogen bonds. An enzyme’s function depends on its structure.

An enzyme’s structure allows only certain reactants to bind to the enzyme. Substrates: reactants that bind to an enzyme Active site: area on the enzyme where substrates bind

Early studies led to the development of the cell theory. The Cell Theory: – All organisms are made of cells. – All cells come from other cells. – The cell is the basic unit of structure & function in living things.

All cells share certain characteristics. Cells tend to be microscopic. All cells are enclosed by a membrane. All cells are filled with cytoplasm. All cells have ribosomes. All cells have genetic material

There are two cell types: eukaryotic cells & prokaryotic cells Eukaryotic cells – Have a nucleus – Have membrane- bound organelles Prokaryotic cells – Do not have a nucleus (still have DNA) – Do not have membrane- bound organelles

Cell Membrane (aka Plasma Membrane) Function: Controls what enters and leaves the cell Made of: – Phospholipids – Proteins – Carbohydrates – Cholesterol – Steroids IN ALL CELLS 1 1 1

Cytoplasm Function: holds organelles in place; location of various reactions in the cell – Organelles: parts of the cell with specific jobs/functions IN ALL CELLS 22 2

Ribosomes Function: protein synthesis – Found in cytoplasm or on the Rough ER IN ALL CELLS

Nucleus Function: Control center of the cell (“brain”) – Has its own membrane – Stores DNA(chromosomes)

Nucleolus Function: Makes RNA (a nucleic acid) – Found inside the nucleus

Endoplasmic Reticulum (ER) Rough ER Helps make and transport proteins Ribosomes on surface make it look rough Smooth ER Helps break down toxins, poisons, and waste Helps process carbs & lipids  “Roadway” of the cell

Golgi Body/Apparatus Function: Packages products (ex. – proteins) for the cell to export – UPS for the cell

Lysosomes Function: Contain enzymes to digest materials for the cell – Not found in plant cells

Mitochondria Function: Where energy is made for the cell Have a double membrane – Inner membrane (cristae) is folded – this increases surface area to allow more energy to be made at a time – Other structures in the body are like this as well (small intestine, lungs)

Plastids Chloroplast Site of photosynthesis (makes food) Chromoplast Make and store pigments in fruits, roots, etc. (red color in tomatoes)  Pigment-containing organelles 6

Vacuole Function: Stores water and food – Plant cells: large and singular – Animal cells: small and numerous

Cell Wall Function: protection for plant, fungal, and bacterial cells 5 5

Selective Permeability Allows some materials to cross the membrane but not all Enables cell to maintain homeostasis – Homeostasis: ability to maintain internal stable conditions Molecules can cross in a variety of ways Other terms: semipermeable & selectively permeable

Passive transport does not require energy (ATP) input from a cell. Molecules can move across the cell membrane through passive transport. Two types of passive transport: – Diffusion: movement of molecules from high to low concentration – Osmosis: diffusion of water

Diffusion and osmosis are types of passive transport. Molecules diffuse down a concentration gradient. – High to low concentration

How do different solutions affect cells? There are 3 types of solutions: 1.Isotonic: solution has the same concentration of solutes as the cell. Water moves in and out evenly Cell size stays constant

How do different solutions affect cells? There are 3 types of solutions: 2.Hypertonic: solution has more solutes than a cell More water exits the cell than enters Cell shrivels or dies

How do different solutions affect cells? There are 3 types of solutions: 3.Hypotonic: solution has fewer solutes than a cell More water enters the cell than exits Cell expands or bursts

Some molecules can only diffuse through transport proteins Some molecules cannot easily diffuse across the membrane – Ex: glucose (needed by cell to make energy) Facilitated diffusion is diffusion through transport proteins Video 

3.5 Active Transport, Endocytosis, & Exocytosis Key Concept: – Cells use energy (ATP) to transport materials that cannot diffuse across a membrane.

Active Transport Drives molecules across a membrane from lower to higher concentration – Goes against the concentration gradient

Endocytosis Process of taking in liquids or larger molecules into a cell by engulfing in a vesicle; requires energy Like Pac man

Exocytosis Process of releasing substances out of a cell by fusion of a vesicle with the membrane – Reverse of endocytosis

Sodium-Potassium Pump Uses a membrane protein to pump three Na + (sodium ions) across the membrane in exchange for two K + (potassium ions) – ATP (energy) is needed to make the protein change its shape so that Na + and K + can move through it and cross the membrane Helps the heart contract, helps regulate blood pressure, allows neurons to respond to stimuli and send signals

PHOTOSYNTHESIS Autotrophic Process: Plants and plant-like organisms get their energy (glucose) from sunlight. Energy is stored as carbohydrate in seeds and bulbs Equation: 6CO 2 + 6H 2 O + sunlight  C 6 H 12 O 6 + 6O 2

PHOTOSYNTHESIS Why do we see green? – Green color from white light reflected NOT absorbed – Chloroplast: organelle responsible for photosynthesis Chlorophyll: located within Chloroplast – Green pigment

PHOTOSYNTHESIS 2 Phases – Light-dependent reaction – Light-independent reaction Light-dependent: converts light energy into chemical energy; produces ATP molecules to be used to fuel light-independent reaction Light-independent: uses ATP produced to make simple sugars.

CELLULAR RESPIRATION Two Types: 1.Aerobic: needs Oxygen 2.Anaerobic: does NOT need Oxygen 3 Stages: 1.Glycolysis 2.Citric Acid Cycle (Kreb’s Cycle) 3.Electron Transport Chain

CELLULAR RESPIRATION 3 Stages: 1.Glycolysis = ANAEROBIC 2.Citric Acid Cycle (Krebs Cycle) = AEROBIC 3.Electron Transport Chain = AEROBIC

CELLULAR RESPIRATION FERMENTATION – 2 Kinds: 1.Lactic Acid 2.Alcoholic Both kinds only use GLYCOLYSIS – How many ATPs does that mean they make?