Reproduction For organisms to reproduce sexually, each parent donates a cell to produce a new organism. A sperm cell joins an egg cell to combine genetic information. Meiosis is a reproduction cycle that involves a combination of an egg and a sperm cell. Meiosis occurs in gonads of organisms
Reproducing the cell Cells produce copies of themselves to make new cells. There three reasons why cells make new cells: Growth: Many living organisms start as single cells made from sperm and egg fusion. Single cells then multiply to produce thousands of copies. Most of the growth is by
Introduction Photosynthesis is the process by which light energy (from the sun) is transferred into chemical energy that can be utilized by living things. Photosynthesis can be represented by the chemical equation below: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2 Getting what plants
Cellular respiration Cellular respiration is a metabolic process that rearranges atoms in molecules of food through multiple steps to ensure that stored food is available to cells. The pathway involves redox reactions that move electrons between molecules and energy transfer. This occurs in the following steps: During respiration in
Metabolism Cells constantly convert energy and matter from one form to another to stay alive. Metabolism refers to all chemical reactions of cells. Metabolism is divided into two: Catabolism This involves all reactions that break complex molecules into simpler ones. Catabolic reactions promote energy transfer from food to a
How cells communicate Cells live in environments with numerous signals. Cels take up materials from the environments across plasma membranes. Transport across membranes Two factors determine whether materials can cross the plasma membrane. Size: Small molecules can cross the plasma membrane faster than larger molecules. Attraction to water: hydrophobic
Lipids are molecules that cannot dissolve in water. Cells synthesize most lipids including phospholipids, sterols, and fats. Structure of lipids All lipid molecules are hydrophobic. Lipids are hydrophobic because they have several nonpolar covalent bonds. Unlike other macromolecules, lipids are not polymers. According to their structures, lipids are divided
Nucleic Acids The genetic code in cells is made up of DNA. DNA specifies the construction of proteins and the generation of RNA. DNA and RNA are nucleotide polymers. Structure of nucleic acids Nucleic acids are information molecules in cells. Deoxyribonucleic acid is the most famous nucleic acid. Ribonucleic
Introduction Most cellular jobs are performed by proteins Proteins interact with other molecules in specific ways to perform cellular functions Levels of protein structure Proteins are amino acid polymers The amino acid polymer is called a polypeptide Once polypeptides are functional after being folded, the polypeptides are called proteins
Structure of Carbohydrates Carbohydrates are molecules made up of hydrogen, oxygen, and carbon There are two main types of carbohydrates: Monosaccharides– known as simple sugars eg glucose Polysaccharides- they are complex carbohydrates Monosaccharides This is single sugars They have a generic formula; CH2O They are colorless and crystalline solids