Presentation on theme: "Chapter 2: How Cells Function"— Presentation transcript:
1 Chapter 2: How Cells Function 2.1: Chemical reactions take place inside cells2.2: Cells capture and release energy2.3: Materials move across the cell’s membranesWill learn:-About the types of elements found in all cells-the functions of the large molecules in the cell-Why water is important to the activities of the cellHave already learned:-All living things are made of cells-Cells need energy to sustain life-Plant and animal cells have similarities and differences
2 Warm-up Questions True for animal cells, plant cells, or both? They need energy to sustain lifeThey have organellesThey have cell walls
3 All cells are made of the same elements The matter that makes up the cell itself is too small for a light microscopeAll matter broken down into elements, each with own characteristicsExample:Oxygen, on Earth, found as colorless odorless gas25 elements (of ~100 on Earth ) are essential for life6 elements account for about 99% of the mass of our bodies!Oxygen: 65%, Carbon: 18.5%, Hydrogen: 9.5%, Calcium: 1.5%, Phosphorus: 1.0%, all other 19: 1.2%
4 Elements Smallest unit of an element: atom In our body: RANK- simple to complex:cell, atom, moleculeSmallest unit of an element: atomIn our body:mostly in the form of compounds – atoms of two or more elements chemically bondedO + O = O C + O + O = CO2Most cellular activities: atoms and molecules interacting via chemical reactions (bonds broken and formed to make new molecules)Need and release energy! Chemical energy!
5 Large molecules for cell function 1) Carbohydrates2) Lipids3) Proteins4) Nucleic AcidsALL have carbon atomsWork together in a cell
6 Carbohydrates Provide the cell with energy Also structureBreaking the bonds within the cell releases energySimple carbohydrates – carbon, oxygen, hydrogenComplex carbohydrates – simple linked into chains: starch, cellulose, glycogenPlants: energy not used makes starches and cellulose (cell wall)Animals eat plants and get energy
7 Lipids Fats, oils, and waxes Similar to carbohydrates, also made of carbon, oxygen, and hydrogenCells use lipids for energy and making structuresAtoms arranged differently than carbohydratesDo not dissolve in water!Cannot mix with water(important for cell membranes…)
8 Proteins Made of amino acids Carbon, oxygen, hydrogen, nitrogen, and sometimes phosphorus and sulfurLinked into long chains, folded into 3-D shapesStructure and function determined by type, number, and order of the amino acidsWe get amino acids from food:meats, eggs, cheese, beans, or created by bodyDifferent types: enzymes (control chemical reactions in cells), others support growth and repair, muscle movement, fight infections, deliver oxygen, form part of the cell membranes
9 Nucleic AcidsHold instructions for the maintenance, growth , and reproduction of a cellDNA – Deoxyribonucleic acidRNA – Ribonucleic acidBoth made of carbon, oxygen, hydrogen, nitrogen, and phosphorus.Subunits called nucleotidesDNA: information used by the cell for making all the protein the cell needsNucleotide pattern in DNA is copied to RNA, which delivers information into the cytoplasm…where it controls chemical reactions and form structures.
10 Two thirds of all cells is water All chemical reactions inside the cell take place in waterWater makes up:46% of body’s mass inside cells23% outside cells in body fluidsPolar: slight positive charge near hydrogen atoms, slight negative near oxygenAttract opposite charges, repel likeMany substances dissolve in water
11 Water & Cells Most lipids do NOT dissolve in water Cell membrane is made of a double layer of lipidsHead is polar, tail is not polarCell membrane is a boundary, keeping the inside of a cell separate from the outsideWater-hating tails repel water