Human Bio, Exam 1 Study Guide
Human Bio, Exam 1 Study Guide BSC 2023
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This 9 page Study Guide was uploaded by Eleonora Sacks on Sunday January 31, 2016. The Study Guide belongs to BSC 2023 at Florida International University taught by Paul Sharp in Spring 2016. Since its upload, it has received 313 views. For similar materials see Human Biology in Biology at Florida International University.
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Date Created: 01/31/16
Exam 1 Study Guide 02/01/2016 ▯ Living Organisms Basic characteristics of living organisms: Organized (has cells, sistems, etc) Ability to reproduce Have homeostasis Respond to stimuli Acquire and store energy and materials Have an evolutionary history Grow and develop Homeostasis: body equilibrium, the body’s internal environment remains constant and between physiological limits. Negative feedback: reduces and eliminates changes in the body, allows homeostasis. Eg: sweating when hot to get back to normal temperature. Osmosis: diffusion of water Tonicity: the osmotic characteristics of a solution across a membrane. Isotonic: a solution that has the same concentration of water and non diffused solutes on both sides of a membrane. Hypertonic: a solution that has high concentration of solutes and low concentration of water outside the cell. Hypotonic: a solution that has a low concentration of solutes and high concentration of water oustide the cell. ▯ ▯ Cell Smallest unit that has life. There are over 200 different types of cells in the human body There are over 50 to 60 trillion cells in the human body. They are so small because they need a large surface area to volume ratio (the distance between the nucleus and the membrane has to be smaller so that materials can get to and from the nucleus faster). Diffusion: when molecules go from being in a place of high concentration of them to a place where there is low concentration of them. Also how materials and nutrients get into the cell. Requires no energy (Passive transport). Cell theory: ▯ 1. Cell: basic unit of life ▯ 2. All living things are made of cells ▯ 3. New cells only arise from preexisting cells Types of cells: Eukaryotes: have membrane bound nucleus and organelles. Eg: animal and plant cells. Prokaryotes: nonmembrane bound nucleus and organelles. eg: Bacteria Parts of the cell: Plasma membrane: regulates what enters and leaves the cell, the boundary between outside and inside the cell. Selectively permeable. Composed of a phospholipid (has a head that is hydrophillic and a tail that is hydrophobic) bilayer, sugars and embedded proteins (some allow materials to pass through them). Named the Fluid Mosaic Model (named for the changing location and patterns of protein molecules in fluid phospholipid bilayer) Facilitated transport: type of passive transport that uss a plasma membrane carrier (proteins) to carry a substance into or out of a cell, going from a higher concentration to a lower one. Active transport: use of plasma membrane carrier to carry substance from higher to lower transportation. Requires energy (usually ATP). Eg: sodium potassium pump Metabolism: chemical reactions that happen in the cell Enzymes: proteins that speed up chemical reactions by lowering the required activation energy (the lowest amount of energy needed for it to happen) Active site: on the surface of an enzyme, it’s where the substrate binds and the reaction occurs. Specific to each substrate (like a keyhole) Substrate: reactant in the reaction that is controlled by enzyme. (like the key) Mitochondria: organelle with 2 membranes responsible for cellular respiration (converts glucose into ATP) Cellular respiration formula: ▯ Parts of the mitochondria: Cristae: folded extensions of the inner membrane that produce ATP Matrix: gellike fluid inside the inner membrane that contains enzymes for breaking down glucose found between the cristae. Intermembrane space: found between the two membranes Bomb calorimeter: measures the amount of calories in food Pathways of cellular respiration: Glycolisis: o Happens in the cytoplasm. o Doesn’t need oxygen (anaerobic) o Produces 2 ATP o Break down of glucose: splits a molecule of glucose C into 2 6 pyruvates of C 3 o Converts 2 molecules of NAD+ (a coenzyme that carries hydrogen and 2 electrons) into NADH. Citric Acid cycle/Kreb cycle: o The pyruvates enter the mitochondria’s matrix and are broken down further and produce 2 ATP per glucose molecule o Happens in the matrix o Aerobic process (needs oxygen) o NAD+ accepts hydrogen and electrons and converts to NADH Electron transport chain: o Happens in the inner membrane of the mitochondria o Electrons pass through membranebound carrier molecules from a higher energy level to a lower energy level. o Hydrogen is moved to the intermembrane space by active transport o Oxygen makes the electrons go from one carrier to the next (like a parent making their child go down the slide) o When the electrons move, energy is released, and it is used to pump the hydrogen into the intermembrane space. o The hydrogen wants to go back to the matrix because of diffusion (it’s in a high concentration in the intermembrane space), so it passes through a protein that spins and produces ATP o The electrons and hydrogen come from the NADH o Produces H2O and 32 ATP ««Remember: ATP is like a dollar bill, NAD+ is like a giftcard without money, and NADH is like a giftcard with money for a specific time and place»» Fermentation: anaerobic process. Allows the NADH to release its electrons and its hydrogen to pyruvate. Converts pyruvate to lactate to do this. Produces 2 ATP per glucose. Yeast produces alcohol and C02 Endocytosis: a portion of the plasma membrane invaginates to envelop a substance or fluid. Types: Phagocytosis: solid particles Pinocytosis: fluids Receptormediated: uses membrane protein receptor to concentrate specific molecules. Exocytosis: vesicles in cell fuse with the plasma membrane during secretion (reverse of endocytosis) Eg: Neurotransmitters, hormones. Cytoplasm: cytosol and organelles Cytoskeleton: mantains cell shapes, anchors organelles and allows cell movement. Composed of: Microtubules: long hollow protein cylinders found in the cytoplasm and in cilia and flagellas, used as tracks for organelle movement. Intermediate filaments: protein fibers that provide strength and support Microfilaments: actin protein fibers that move cell and organelles (like little motors) Centriole: short cylinders of microtubules that divide and organize spindle fibers during mitosis and meiosis Centrosome: 2 centrioles that function as a microtubule organizing center. Active during cell division. Nucleus: houses chromosomal DNA Nuclear envelope: double membrane that encloses nucleus with nuclear pores Chromatin: diffuse threads containing DNA (DNA not in form of chromosomes) Nucleolus: region that produces subunits of ribosomes. Nucleoplasm: semifluid medium inside nucleus Nuclear pores: allow ribosomal subunits to exit and proteins to enter. Ribosomes: synthesize proteins using mRNA (messenger RNA: a copy of DNA that has genetic information) template Endomembrane system: a series of membraneous organelles that process materials for the cell: Nuclear envelope E.R. (endoplasmatic reticulum): continuous of the nuclear envelope, has saccules and channels: Rough E.R.: has ribosomes embedded on the side that faces the cytoplasm. The ribosomes synthesize proteins and then the proteins enter the ER interior for processing and modifications Smooth E.R.: has no ribosomes. Synthesizes phospholipids. Golgi apparatus: modifies lipids and proteins from the ER and sorts, packages and distributes molecules synthesized by cell (like the Fedex of the cell) Lysosomes: membraneous sacs produced by the Golgi, contain hydrolitic enzymes that break down things inside them. Can fuse with endocytic vesicles. Vesicles: tiny membraneous sacs Meiosis: cell division in sperm and ovules (only in sexual reproduction). Daughter cells receive haploid number of chromosomes in varied combinations. Mitosis: cell division for growth, development and repair. Daughter cells receive exact chromosomal and genetic info that parent cell has. Cell cycle: repeating sequence of cellular events 1. Interphase: has 3 stages: a. Growth (G1): cell returns to normal phase, resumes its functions and doubles its organelles b. Synthesis (S): DNA replication (now a chromosome has 2 sister cromatids) c. Growth (G2): increase in growth and final preparations for division 2. Mitosis 3. Cytokinesis: division of cytoplasm ▯ ▯ MITOSIS AND DNA REPLICATION DNA (deoxyribonucleic acid): composed of two complimentary strands of nitrogenous bases (Thymine (T), Cytosine (C), Adenine (A) and Guanine (G)). Never leaves the nucleus. Has a sugarphosphate backbone (sugar is deoxyribose) and the nitrogenous bases are like the rungs of a ladder. (always T+A, G+C) Centromere: part of the chromosome where the sister chromatids attach, also where the mitotic spindle attatches to separate them. Mitotic spindle: formed by centrosomes where microtubules move chromosomes DNA replication: happens during S phase of the interphase. The original strand of DNA is ‘unzipped’ by enzymes and each strand is completed by a new strand with the complimentary bases of each part. (Green= old strand, yellow= new strand) ▯ ▯ Chareotype: shows the 23 pairs of homologous chromosomes laid out. (similar in size and colour, the pair has the same genes for hair, etc, but not the same sequence because one comes from the mother and the other from the father) Mitosis: daughter cells are identical to father cells Prophase: centrosomes form and shoot microtubules (formation of the mitotic spindle starts) and the nuclear envelope breaks down. Metaphase: chromosomes align in the middle of the cell and the mitotic spindle is fully formed Anaphase: sister chromatids are separated and pulled to opposite sides of the cell Telophase: mitotic spindle breaks down, nuclear envelope rebuilds Cytokinesis: cleavage furrow allows cytoplasm to divide. Cancer: mutations. Sometimes during replication, enzymes make mistakes. A cancer cell cannot communicate with other cells so they continue to grow even when it is no longer needed. Checkpoints: if a mistake during replication happened, these checkpoints ensure that it’s taken care of. (sometimes it also fails) G1 and G2: apoptosis (cell death) will happen if DNA is damaged and can’t be repaired M: mitosis doesn’t occur if cells aren’t aligned correctly. Diploid: 46 chromosomes in humans, “2n” Haploid: 23 chromosomes in humans, “n” ⬅MEIOSIS II ▯ ⬅ MEIOSIS I ▯ MEIOSIS: Only sex cells (sperm and eggs) Goal: produce haploid cell Meiosis 1: reductional division (homologous pairs separate), 1 cell produces 2 haploid cells Prophase 1: chromosomes have duplicated, mitotic spindle starts, nuclear envelope starts to break down. Crossing over: homologous pairs synapse (‘get freaky’), where they cross or join, they exchange material, that place is called the chiasmata. Crossing over increases genetic variability. Metaphase 1: homologous pairs align in the middle of the cell. Independent assortment: random orientation of the homologous pairs. Anaphase 1: whole cromosom is pulled apart (the pairs are separated) Telophase 1: interkinesis (type of cytokinesis) occurs. Same as mitotics telophase Meiosis 2: sister cromatids separate, produces 4 haploid cells Prophase 2: no crossing over (this only happens in prophase 1, meiosis 1). The nuclear envelope breaks and the spindle begins to form Metaphase 2: the chromosome aligns in the middle Anaphase 2: sister cromatids are separated Telophase 2: same as mitotis telophase, interkinesis also takes place. ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ⬅ Legend Spermatogenesis: production of sperm. Starts off with one sperm that produces 4 viable sperm cells. Starts in puberty. ▯ ▯ ▯ ▯ < Oogenesis ▯ ▯ Oogenesis: production of eggs. 1 viable egg is produced. Starts since the baby girl is in the womb. The secondary oocyte will only go through meiosis 2 if it has been fertilized by a sperm. Polar body: has the same genes as the oocyte ▯ ▯ GENETICS Gene: DNA sequence found in chromosomes Allele: version of a gene (for the gene of hair color, there are alleles for dark hair, blond, red, etc) Locus: site where the gene is on the chromosome Genotype: genetic information responsible for a specific trait (written as Aa, BB, cc) Phenotype: the physical expression of a gene (blue eyes, long fingers) The capital letter (A) means that the gene is dominant (masks the other gene), while a lowercase letter (a) means that the gene is recessive (will only express itself in the phenotype if the other gene is also recessive aa) Heterozygote: two different alleles for a gene (Aa) Homozygote: two of the same alleles for a gene (AA, aa) Punnet square: the female always goes on top, the male goes downwards. ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ ▯ Phenotypic ratio: proportion of dominant:recessive. eg: the ratio for the punnet square above would be 3:1. ⬅Punnet square Dominant always masks the recessive in a heterozygote Principle of segregation: 2 alleles of a gene segregate during gamete formation and are rejoined at random during fertilization. (like independent assortment) Remember: heterozygote is a capital letter and a lowercase letter (Aa) Incomplete dominance: happens when the heterozygote is intermediate between the 2 homozygotes. Eg: you have HH= straight hair, hh= curly hair but Hh= wavy hair. If the parents are HH and hh, all of the children will be Hh and therefore have wavy hair. Codominance: happens when alleles are equally expressed in the heterozygote (one doesnt mask the other) (eg: blood type) Multipleallele inheritance: inheritance pattern in which there are more than 2 alleles for a particular trait. eg: blood type, because A, B, O Polygenic inheritance: inheritance pattern in which more than 1 gene affects a trait. eg: skin tone, height3 genes involved in these: A,B,C Autosomes: any chromosomes other than the sex chromosomes Sex chromosomes: determine the sex of an individual (XXfemale,XYmale) Sexlinked: refers to an allele that occurs on the sex chromosome but may control a trait that has nothing to do with the sex characteristics of an individual. Xlinked: refers to an allele located on the X chromosome. eg: XB normal vision, Xb=red/green colorblind Pedigree: a graphical representation of matings of offspring over multiple generations for a particular trait (like a family tree that indicates the family members' genotype and phenotype). How to do pedigree problems: look at each trait and do a punnet square to find the parents' possible genotype. ▯ ▯ ▯
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