General Biology Reviewer PDF

**GENERAL-BIOLOGY** **CELL MEMBRANE** **MEIOSIS** Sexual Reproduction Makes a more genetically diverse population Asexual Reproduction (no sex- like in a bacteria) is great in a stable environment But Sexual reproduction and its genetic diversity are key to survival in a changing environment....

**GENERAL-BIOLOGY** **CELL MEMBRANE** **MEIOSIS** Sexual Reproduction Makes a more genetically diverse population Asexual Reproduction (no sex- like in a bacteria) is great in a stable environment But Sexual reproduction and its genetic diversity are key to survival in a changing environment. GAMETES are required for sexual reproduction GAMETS = eggs and sperm Meiosis helps in making gametes So Meiosis makes sexual reproduction possible A few facts about the human gametes For males, Sperm are made fresh daily For females All the eggs a woman are made before she was born Females release one egg every month once they hit puberty Sometimes they release two or three. This is when Fraternal twins and Fraternal triplets can be conceived. Why Meiosis? Humans have 46 chromosomes in each cell which is called (full set) diploid A baby needs a TOTAL of 46, in the first cell. 23 from Mom, 23 from 23(haploid) = 46 There are 8 phases in Meiosis Meiosis Produces Sperm in Males Diploid cell (with 46 chromosomes) After Meiosis1, we get 2 haploid cells After Meiosis 2, we get 4 haploid cells. Meiosis Produces Sperm in Males Diploid cell (with 46 chromosomes) After Meiosis 1, we get 1 large haploid cell and a polar body. After Meiosis 2, we get 1 large haploid cell and 3 polar bodies. CELL MEMBRANE TRANSPORT MECHANISM Cell Transport How things move in or out of the cell through the cell membrane. Two Broad Categories PASSIVE TRANSPORT Automatic No energy input required Types of Passive Transport Diffusion -can happen with or without a semi-permeable membrane. -is when particles move from one area of high concentration to low concentration. ACTIVE TRANSPORT Energy is required Lower to higher concentration TYPES -Endocytosis Phagocytosis Takes nutrients -Pinocytosis Takes fluid -Exocytosis Something needs to exit the cell. (Lipids: 40%, Proteins: 55%, Carbohydrates: 5%) Also called Plasma membrane Plasmalemma Wall of the cell Maintains shape and size of the cell Lipids Phospholipids Are by far the most abundant among them. Hydrophilic (Phosphate head) Hydrophobic (Lipid Tail) Cholesterol OSMOSIS Is a process by which the molecules of a solvent pass from a solution of low concentration to a solution of high concentration through a semi-permeable membrane. THREE DIFF. TYPES OF OSMOTIC SOLUTION Isotonic Solution- is one that has same concentration of solutes both inside and outside of the cell. Hypertonic Solution- higher concentration outside than inside. Hypotonic -- higher concentration inside than b outside. TYPES OF OSMOSIS Endosmosis a substance is placed in a hypotonic solution. Exosmosis a substance is placed in a hypertonic solution Toxicity refers to the relative concentration of solutes inside and outside of the cell. PROTIEN Molecules which yield amino acids upon hydrolysis are called proteins Nitrogen, carbon, hydrogen and oxygen Classification of Protein Simple Proteins those which give one amino acid only upon hydrolysis Conjugated Proteins Those which give an amino acid and a non-protein group upon hydrolysis Derived Protein Those which are derived from simple and conjugated proteins STRUCTURE OF PROTEINS Primary Structure -The sequence of amino acids in a polypeptide chain called a primary structure. Secondary Structure -be present in a zigzag manner (coiling peptides) Tertiary Structure -twisting or folding of polypeptide chains represents tertiary structure of proteins. Quaternary Structure -arrangement of multiple folded protein or coiling protein molecules in a multi subunit complex. CARBOHYDRATES Organic compounds made of carbon, hydrogen, and oxygen atoms. Carbohydrates are ones of the main macro nutrients are vital for energy production. BASIC UNIT OF CARBOHYDRATES The simplest units of carbohydrates are monosaccharides such as glucose, fructose, and galactose. TYPES OF CARBOHYDRATES Simple Carbohydrates: -Monosaccharides -Disaccharides Complex Carbohydrates -Polysaccharides Monosaccharides are composed only of 3 to 7carbon atoms one sugar unit. \>Fructose "fruit sugar" \>Galactose "milk sugar" \>Glucose "blood sugar" Disaccharides two mono. Join together and molecule of water is removed \>glucose \>fructose \>sucrose Polysaccharides composed of long chains of mono units linked together by glycosidic bonds. MAIN FUNCTIONS OF CARBOHYDRATES Energy Source Energy Storage Structural Role Sparing Protein NUCLEIC ACIDS Nucleic acids are long-chain polymeric molecules present in living cells. They are made of carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and phosphorus (P). In the nucleus, nucleotide monomers are linked together comprising of distinct components namely a Phosphate Group, Nitrogenous Bases or Ribose and Deoxyribose. Pyrimidines and Purines are two types of nitrogenous bases. Pyrimidines are composed of cytosine and thymine. Purines are composed of guanine and adenine. Thymine is replaced by Uracil in ribonucleic acid whereas deoxyribonucleic acid comprises of all four bases. Basic Units of Nucleic Acids PHOSPHATE GROUP this is like a connector that links the nucleotides together. SUGAR a type of sugar called deoxyribose in DNA and ribose in RNA. NITROGENOUS BASE there are four possible bases in DNA. Adenine (A) Thymine (T) Cytosine (C) Guanine (G) In RNA, Uracil (U) replaces Thymine Types of Nucleic Acid DNA (Deoxyribonucleic Acid) Store genetic information and is found mostly in the nucleus of cells. RNA (Ribonucleic Acid) Helps in the process of making proteins. There are different types of RNA, like Mrna (messenger RNA), Trna (transfer RNA), and Rrna (ribosomal RNA) DNA STRUCTURE DNA consists of instructions that monitor the performance of all cell functions. It is a cellular molecule that is organized into chromosomes. They are present in the nucleus of the cells and contain cellular activities. RNA plays a vital role in the synthesis of proteins that mainly involves decoding and translation of genetic code and transcription to produce proteins. Types of RNA Ribosomal RNA -- It is one of the components of ribosomes that are involved in protein synthesis. Transfer RNA -- It is essential for the translation of mRNA in protein synthesis. Micro RNAs -- It is the smallest among all RNA that helps in regulating gene expressions. Messenger RNA -- It is the RNA transcript that is produced during DNA transcription. Functions of Nucleic Acids Nucleic Acid is responsible for the synthesis of protein in our body RNA is a vital component of protein synthesis. Loss of DNA content is linked to many diseases. DNA is an essential component required for transferring genes from parents to offspring. All the information of a cell is stored in DNA. DNA fingerprinting is a method used by forensic experts to determine paternity. It is also used for the identification of criminals. It has also played a major role in studies regarding biological evolution and genetics. Basic Structure Nucleic acids are polynucleotides---that is, long chainlike molecules composed of a series of nearly identical building blocks called [nucleotides](https://www.britannica.com/science/nucleotide). Each [nucleotide](https://www.britannica.com/science/nucleotide) consists of a [nitrogen](https://www.britannica.com/science/nitrogen)-containing aromatic base attached to a pentose (five-[carbon](https://www.britannica.com/science/carbon-chemical-element)) [sugar](https://www.britannica.com/science/sugar-chemical-compound), which is in turn attached to a [phosphate](https://www.britannica.com/science/phosphate) group.