Biology Exam Review PDF

UNIT 1 GENETICS Terms 1.​ Allele: alternate form of a gene -​ Caused by differences in sequences of the DNA at a specific position within the gene -​ Codes for specific genes like blue or brown eyes 2.​ Chromosome: physical structure that stores genetic info...

UNIT 1 GENETICS Terms 1.​ Allele: alternate form of a gene -​ Caused by differences in sequences of the DNA at a specific position within the gene -​ Codes for specific genes like blue or brown eyes 2.​ Chromosome: physical structure that stores genetic info -​ Composed of long strands of DNA coiled around proteins 3.​ Sister chromatid: identical copies of chromatids formed by DNA replication of a chromosome and are joined together by a centromere 4.​ Daughter chromosome: sister chromatids join together to be a daughter chromosome -​ Once broken apart they become sister chromatids once again 5.​ Chromatin: mixture of DNA & histone proteins -​ Uncoiled form of chromosomes/dna 6.​ Genotype: combination of alleles ex, Cc or CC 7.​ Phenotype: physical appearance of an organism's traits ex, black fur 8.​ F1 generation: offspring of P generation 9.​ F2 generation: offspring of F1 generation 10.​ Homozygous: Both alleles are identical -​ Both alleles recessive or dominant -​ Ex, CC or cc 11.​Heterozygous: alleles are different -​ Dominant allele typically expressed -​ Ex, Cc -​ Individual can still pass down recessive allele to offspring 12.​Recessive: alleles or traits only expressed when both alleles are present -​ Ex cc -​ Will not be expressed if genotype is Cc 13.​Dominant: alleles or traits represented regardless of the identity of the other allele -​ Represented if Cc or CC 14.​Nucleotide: basic unit of DNA -​ Consists of sugar group, phosphate group & nitrogenous base 15.​ Nitrogenous base: a molecule that contains nitrogen and is a key component of DNA and RNA, the genetic material of cells  →4 types of nitrogenous bases. -​ Adenine -​ Thymine -​ Cytosine -​ Guanine →A and T bond together (2 hydrogen bonds) →C and G bond together(3 hydrogen bonds) -Thymine and cytosine are pyrimidines(1 ring) -Adenine and Guanine are purines(2 rings) Cell Cycle MITOSIS- the process of asexual reproduction in our body cells INTERPHASE: (not part of mitosis) -​ 90% of a cell’s life -​ G1: Major period of growth for a cell, cell is synthesizing it’s molecules for the next stage -​ S: CHROMATIN (DNA) is being synthesized or replicated -​ G2: Synthesizing more molecules​ PROPHASE: -​ Chromatins condense and coils into chromosomes -​ Centrioles move to the poles of the cells and creates spindle fibers from centrosomes -​ Nuclear membrane begins to dissolve METAPHASE: -​ Spindle fibers attach to the centromere of the chromosomes and moves them to the equatorial plate of the cell ANAPHASE: -​ Sister chromatids are pulled apart and moved to opposite sides of the cell and are now called chromosomes -​ Centromere is split in two TELOPHASE: -​ Chromosomes decondense into chromatin again -​ Spindle fibers break down -​ Nuclear membrane begins to form around set of chromosomes then nucleus forms  -​ MEIOSIS: sexual reproduction that creates sex cells in testes and ovaries; Gametes Two goals: -​ Genetic reduction: the daughter cells, HAPLOIDS, are HALF the number of chromosomes of the parent cell, DIPLOID -​ Genetic recombination: The haploids have shuffled alleles, resulting in genetic variation in offspring. PROPHASE I -​ Begins as a diploid (eg. 46 DOUBLE STRANDED CHROMOSOMES) -​ Nuclear membrane begins to dissolve -​ Centrioles move to poles & form the spindle fibers -​ SYNAPSIS: the alignment of homologous chromosomes(maternal and paternal chromosome with the same centromere, gene location etc) and pair up to form a tetrad -​ CROSSING OVER: During the alignment, the homologous chromosomes exchange DNA, resulting in unique chromosomes METAPHASE I -​ Homologous pairs are each pulled to the equatorial plate of the cell by the spindle fibers attaching to their centromeres -​ INDEPENDENT ASSORTMENT: Homologous chromosomes may get sorted in numerous ways and a number of different combinations, resulting in different possibilities for the haploids. ANAPHASE I -​ Spindle fibers pull apart the homologous chromosomes, so one double stranded chromosome from each homologous pair move to the opposite pole of cell -​ The chromosome number goes from 2n →n TELOPHASE I -​ Homologous chromosomes begin to uncoil into chromatin -​ Spindle fibers break down -​ Nuclear membrane forms around each group of chromosomes -​ Cytokinesis takes place - CLEAVAGE FURROW: animal cell pinching from the outside - The cells are now a HAPLOID (23 number of double stranded chromosomes) PROPHASE II -​ Begins with haploid number (23 ds chromosomes) -​ Chromatins condense into chromosomes -​ Nuclear membrane begins to dissolve -​ Spindle fibers are formed from the centrosomes -​ Centrioles move to opposite poles of cell METAPHASE II -​ Spindle fibers bring chromosomes to equator of cell ANAPHASE II -​ Sister chromatids are pulled apart from each other to the opposite poles of the cell -​ Centromeres split TELOPHASE II -​ Nuclear membrane forms around both groups of chromosomes -​ Chromosomes uncoil into chromatin again -​ Ends in cytokinesis, where 4 haploid cells are formed, each with 23 single stranded chromosomes -​ Mitosis Comparison Meiosis 1 phases 2 Growth & repair of purpose Genetic reduction & somatic cells genetic recombination asexually Type of reproduction sexually Body cells (somatic cells) Type of cell Germ cell to produce Sperm and egg diploid Starting cell diploid 2 identical daughter cells Ending cell 4 non identical haploid from a diploid cell cells Chromosomes line up Metaphase In metaphase 1, pairs of along the middle of the homologous cell chromosomes called tetrads line up along the middle of the cell. In metaphase 2, chromosomes line up along the middle of the cell (like mitosis) Sister chromatids are Anaphase In anaphase 1, homologous pulled apart to opposite chromosomes are pulled sides of the cell apart In anaphase 2, sister chromatids are pulled apart;breaking up the chromosome  Genetically identical Genetic composition Genetically different due to independent assortment and crossing over -​ Meiosis phase 2 is more similar to mitosis as the homologous chromosomes have been broken apart in phase 1 Stages that contribute to genetic variation include 1.​ Prophase 1 -​ Homologous chromosomes pair up to form a tetrad and exchange genetic material through crossing over; resulting in a new combination of genes 2.​ Metaphase 1 -​ Homologous chromosomes line up along the middle of the cell randomly; independent assortment 3.​ Anaphase 1 -​ Homologous chromosomes are separated -​ Since the chromosomes segregate randomly, each daughter cell receives a unique mix of chromosomes Diploid vs Haploid -​ Diploid 2n refers to the total number of chromosomes in a cell -​ Haploid n is half the number and represents the number of chromosomes in a single set -​ Diploid cells (2n=46) found in somatic cells & they contain 23 pairs of chromosomes -​ Haploid (n=23) are found in gametes and contain a single set of 23 chromosomes -​ Ex. if an organism has a diploid number of 26 chromosomes, the haploid number would be 13 because haploid is half of diploid Genotype vs Phenotype -​ Genotype refers to the genetic makeup of a characteristic within an organism and a phenotype is the physical appearance of that specific characteristic within that organism Inheritance patterns 1.​ Mendelian inheritance: traits governed by a single gene with two alleles ex. T=tall t=short T t T TT Tt t Tt tt Phenotypes: 3:1 (Tall:short) Genotypes: 1:2:1 (TT, Tt, tt) 2.​ Sex linked inheritance: traits linked to genes on sex chromosome XN^NN = normal, Xn^nn = color blind X^N Y X^N X^N X^N X^NY X^n X^n X^N X^n Y Phenotype: females: 1 normal, 1 carrier; Males: 1 normal, 1 colour blind 3.​ Codominance inheritance: both alleles fully expressed in heterozygous individuals R^w= white R^r=red R^r R^w R^r R^r R^r R^r R^w R^w R^r R^w R^w R^w Phenotype: 1 red, 2 roan, 1 white 4.​ Incomplete dominance: heterozygous phenotype is intermediate between two homozygous phenotypes R=red W=white R W R RR RW W RW WW Phenotypes: 1 red, 2 pink, 1 white ​ 5.​ Multiple alleles: involves more than two alleles for a gene ex, ABO blood types I^A i I^A I^A I^A I^A i I^B I^A I^B I^B i Phenotypes A:2, AB: 1, B:1 How sex linked traits are expressed (colour blindness) -​ Colour blindness is x-linked recessive meaning a female would need to be homozygous recessive for colour blindness to be expressed whereas for a male he would need to carry a single recessive allele for it to be expressed, making it more common for a male to have it than a female. Chromosome, DNA, allele, gene -​ -​ Punnett square where all 4 blood types are possible  If two heterozygous parents for a disease have a child, what is the likelihood of the child having a disease? Compare these results if the disease was dominant and if the disease was recessive. Assume Mendelian inheritance. What are the mendelian ratios for a dihybrid cross between two heterozygous parents for both traits? What is the mendelian ratio for a monohybrid cross for two heterozygous parents? What are the genotypes of parents if given the number of offspring? -​ Mendelian ratios for a dihybrid cross between two heterozygous parents would me 9:3:3:1 ←when counting, count phenotypes instead of genotype because it represents the phenotypic ratio Ex. B=black b=blond C=curly c=straight If both parents were heterozygous (BbCc) the phenotypes would be 9 black +curly, 3 black + straight, 3 blond + curly & 1 blond + straight -​ Mandelian ratio for a monohybrid cross between two heterozygous parents is 3:1 Ex. G=green g=yellow If both were Gg we would get 3 green and 1 yellow -​ If we get a 9:3:3:1 ratio we can assume that it is a dihybrid cross (2 traits) with 2 heterozygous parents -​ If we get a 3:1 ratio we can assume that it is a monohybrid cross (one trait) with 2 heterozygous parents Karyotype for a female with down syndrome -​ Down syndrome affects chromosome 21 -​ 3 copies of chromosome 21 (Trisomy 21) -​ Would still have XX chromosomes -​  Monosomy Trisomy -​ Missing chromosome -​ Extra chromosomes -​ Ex turner syndrome is a monosomy -​ Ex. down syndrome is a trisomy of the sex chromosomes when a and has 3 copies of chromosome 21 female is missing an X -​ Ex. klinefelter syndrome is another chromosome example where males have an extra X chromosome (XXY) The term best used to describe as error in meiosis is nondisjunction -​ Nondisjunction is the failure of chromosomes or chromatids to separate properly during meiosis resulting in gametes with an abnormal number of chromosomes -​ If nondisjunction occurs in meiosis I then the homologous chromosomes fail to separate -​ If nondisjunction occurs in meiosis II then the sister chromatids fail to separate Crossing over vs Independent assortment 1.​ Crossing over is a process that occurs during prophase I after the homologous chromosomes have formed a tetrad; they exchange genetic material creating new combinations of genes in the gametes which leads to genetic variation in the offspring 2.​ Independent assortment is a process that occurs during metaphase I were homologous chromosomes are randomly separated into haploid cells meaning that the allele the cell receives for one gene is not influenced by the allele it receives for another gene; this creates new genetic combinations Nucleotides Nucleotides are made up of a sugar group, phosphate group & nitrogenous base A Nitrogenous base is made up of -​ Adenine -​ Thymine → 2 hydrogen bonds -​ Cytosine -​ Guanine →3 hydrogen bonds * if im told guanine is 40% of the DNA then because its paired up with cytosine then it will also be 40% leaving 20% left so both adenine and guanine make up 10% of the DNA Sickle cell anemia Sickle cell anemia is when the blood cells are crescent shaped and are unable to transport oxygen -​ Autosomal (not on the sex chromosomes) and recessive -​ It is caused by a mutation in the gene that codes for hemoglobin, this mutation causes hemoglobin molecules to stick together -​ People with sickle cell anemia are immune to malaria -​ Individuals who are heterozygous for sickle cell anemia are able to transport oxygen and are also immune to malaria but still pass down that recessive allele to their future child Spermatogenesis vs Oogenesis Spermatogenesis -​ Begins with diploid cell called spermatogonium -​ Equal division of cytoplasm -​ 4 cells reproduce via meiosis -​ Capable of many mitotic divisions before meiosis -​ Unlimited supply Oogenesis -​ Begins with diploid cell called oogonium -​ Cytoplasm of female gametes does not divide equally -​ One daughter cell receives most of the cytoplasm while the other three polar bodies die and are absorbed by the body for nutrients -​ ONE viable egg -​ Limited supply UNIT 2 EVOLUTION Lamark Difference Darwin 1.​ Use and disuse: Theory 1.​ Descent with parts of the body modification: that are being used species of organism  on a regular basis accumulates become larger while modifications body parts that (mutations) that help aren’t being used them survive local deteriorate conditions at a 2.​ Inheritance of specific time acquired traits: 2.​ Natural selection: characteristics organisms that are developed in a most fit leave most lifetime that were offspring beneficial in the Based of 3 observations environment are -​ Struggle for passed down to existence offspring -​ Natural variations among a species -​ Environment influences evolution Inheritance of acquired Mechanism of evolution Natural selection traits Organisms change during Source of variation Variation is genetic and their lives to adapt to their exists before environmental environment pressures Survival of the fittest Reproductive success is related to survival of the fittest because when an organism has a high fitness it is better adapted to its environment meaning that it is able to produce viable offspring that are able to survive and reproduce. If an organism is able to survive and reproduce it contributes to the gene pool of the next generation Natural selection Natural selection refers to the environment choosing desirable traits that are best adapted to the environment which increases the fitness of an organism. Natural selection is situational because there could be an environmental shift that changes the desirable traits and favors one phenotype over the other -​ Ex. peppered moths going from white trees and white moths to black trees and black moths. White moth start with the advantage but due to the industrial revolution changing the colour of black trees the black moths end up with the advantage Adaptations 1.​ Behavioural adaptations -​ Associated with how an organism responds to their environments ex. Migration of birds & hibernation 2.​ Physiological adaptations -​ Associated with the Internal processes within an organism ex. Venom & temp regulation 3.​ Structural adaptations -​ Physical features of an organism that helps it survive its environment ex. Camouflage & bird beak Bottleneck vs founder 1.​ Bottleneck effect: severe environmental stress (disease, starvation, natural disaster) nearly wipes out a whole population→ rapid decrease in population size -​ Some alleles lost forever because only a small number of people reproduce the next generation 2.​ Founder effect: small number of dispersed individuals establish a new population at a distance from the initial population -​ New population carries only a few alleles of the original population & diversity of the new population is limited -​ Occurs frequently on islands Mimicry Mimicry refers to a harmless creature mimicking the structure of a harmful creature to keep predators away, enhancing fitness and chance of survival.The viceroy butterfly (harmless) mimics the appearance of the monarch butterfly (toxic), making predators avoid it. This mimicry helps the viceroy butterfly avoid being eaten, increasing its chances of survival. Prezygotic and postzygotic mechanisms & allopatric vs sympatric Prezygotic mechanisms 1.​ Behavioral isolation -​ Different species use different courtship and mating cues to find a partner -​ Ex. male frogs of different species have unique calls that attract only females of their species 2.​ Temporal isolation  -​ Different species breed at different times of the year -​ Ex. 3 types of orchids bloom on different days 3.​ Habitat isolation -​ Very similar species may occupy different habitats within a region -​ Ex. mountain bluebird (Sialia currucoides) lives at high elevations, while the eastern bluebird (Sialia sialis) prefers lower elevations and does not encounter the mountain species 4.​ Mechanical isolation -​ Structural differences in reproductive organs prevent successful fertilization -​ Ex. snail shell orientation (can either be left handed or right handed) 5.​ Gametic isolation -​ Male gametes may not recognize and fertilize an egg of a different species or die before uniting -​ Many marine animals release sperm and eggs into the water. The sperm recognize eggs of their own species through chemical markers on the surface of the eggs. Postzygotic mechanisms 1.​ Hybrid inviability -​ Mating and fertilization are possible but genetic differences result in zygote that is unable to develop properly -​ Ex. Some species of sheep and goat are able to mate, but the zygote is not viable 2.​ Hybrid sterility -​ Two species mate to produce a hybrid (offspring is sterile) -​ Ex. mules are sterile (horse-donkey cross) 3.​ Hybrid breakdown -​ The first generation of hybrids are viable and fertile but the second generation are either sterile or weak -​ Ex. different species of cotton plants can produce fertile hybrids, but the offspring of the hybrids die as seeds or early in development. A liger belongs to post zygotic mechanisms specifically hybrid sterility and Hybrid Inviability: While ligers are usually born healthy, hybrids like them can sometimes experience developmental issues or have reduced survival rates in the wild, due to differences in their genetic makeup from their parent species. Hybrid Sterility: Ligers are generally sterile and cannot reproduce. This is because lions and tigers have a different number of chromosomes, and their offspring typically inherit incompatible sets of chromosomes, disrupting normal gamete formation during reproduction. The sterility of ligers is similar to that seen in other hybrids, such as mules (the offspring of a horse and a donkey). Allopatric speciation: physical separation prevents the exchange of genetic information and causes populations, over many generations, to be less and less alike. -​ Population live on remote islands -​ Populations split by the formation of mountains, glaciers, rivers, habitat fragmentation, bodies of water ect. -​ Continental drift Sympatric speciation: -​ Individuals of a population become genetically or reproductively isolated from the larger population 5 types of evidence of evolution 1.​ Fossil evidence -​ Older rock layers deposited under newer rock layers -​ Creates geological time scale -​ Different fossils can be found in each rock layers -​ Transitional fossils: fossil that shows the intermediary links between two groups of organisms of organisms with slightly different features -​ Ex. The modern day whale evolved from the aquatic species dorudon which contained hind limbs. 2.​ Biogeography -​ Study of past and present geographical distribution of organisms -​ Geographically close environments are more likely to be populated by related species than other locations that are geographically different but have the same environment -​ Some species found in areas close to each other are related but look different due to environmental factors -​ Some species found in farther areas look similar due to adaptations to environment but are not related 3.​ Anatomy -​ Homologous structures: similar structural elements and common ancestor but different functions -​ Analogous structures: different structural elements and do not share a common ancestor but perform similar function -​ Vestigial structures: remnants of structures that may have had important use to ancestral species but no longer serve a purpose to the descendants ex. Snakes having legs -​ Homologous structures have similar structures like the images above but although they have the same structural elements, they all serve a different purpose. Although they have the same bone structure, the human arm is used to grab, push, pull things ect and a bat wing is used for light.  -​ Analogous structures have similar functions but different structures like the image above. The bird and bat wing have different bone structures but both help the organism fly 4.​ Embryology -​ Study of early, pre-birth stages of an organism's development -​ Embryos of closely related organisms often have similar stages in development -​ All vertebrate animals have tails during development (some will continue to develop their tails while others do not) 5.​ DNA -​ If two species have similar patterns of DNA, their DNA sequences must have been inherited from a common ancestor Key points of natural selection Natural selection is based on.. 1.​ Variation: Individuals within a population vary in traits, such as size, color, or behavior. These variations can be inherited from one generation to the next. 2.​ Overproduction: Organisms tend to produce more offspring than can survive. This leads to competition for resources such as food, space, and mates. 3.​ Competition: Since resources are limited, individuals must compete for survival and reproduction. Some individuals are better suited to the environment than others due to their traits. 4.​ Differential Reproduction: Individuals with traits that are better suited to the environment are more likely to survive, reproduce, and pass on those beneficial traits to their offspring, while individuals with less advantageous traits are less likely to reproduce. Stabilizing selection  -​ Intermediate phenotype favoured over 2 extremes -​ Reduces variation and improves population -​ Represented as ↓↑↓ Directional selection -​ Favours one extreme over the other -​ Represented as ↓↓↑ or ↑↓↓ Disruptive selection -​ Favours both extremes over intermediate phenotype UNIT 3 ANIMAL SYSTEMS Main functions of circulatory system The main functions of circulatory system include  -​ Transport oxygen, carbon dioxide, distributes nutrients and removes waste -​ Regulates body temperature, circulates chemical/ hormones -​ Protects against blood loss, disease-causing microbes and toxic substances Deoxygenated blood -​ Collected through the superior and inferior vena cava -​ Enters through the right side of the heart through the right atrium, passing through the tricuspid valve and into the right ventricle -​ The right ventricle contracts and pumps the deoxygenated blood through the pulmonary valve and into the pulmonary artery towards the lungs -​ After reaching the lungs, gas exchange occurs; inhaled oxygen passes through the alveoli and into the blood in the capillaries and carbon dioxide from the blood moves into the exhaled air. Oxygen diffuses across thin walls of alveoli and enters the capillaries where it binds to red blood cells and travels back to the heart. Simultaneously, the carbon dioxide diffuses from the blood into the alveoli to be exhaled Oxygenated blood -​ After the oxygenated blood travels back to the heart through the pulmonary vein, it enters the left atrium which contracts, passes through the bicuspid valve and enters the left ventricle -​ After reaching the left ventricle it contracts, pushing the blood through the aortic valve and into the aorta for it to travel to the rest of the body Blood pressure measurements 1.​ Stethoscope -​ Placed on artery (brachial) to hear changes in heart sound 2.​ Sphygmomanometer (BP cuff) -​ Secured to the upper right arm to measure blood pressure in mm in mercury (mmHg) Average blood pressure -​ Systolic pressure: 120 -​ Diastolic pressure: 80 Vasodilation; dissipation of heat in the body -​ Process in which blood vessels widen or expand; occurs when smooth muscles in the walls of blood vessels relax, allowing the vessels to increase in diameter -​ Increases blood flow to certain areas of the body that can help regulate body temp by releasing heat  -​ Triggered by factors like increased body temp, lower oxygen levels, or the presence of certain chemicals like nitric acid Major organs/structures in the body systems 1.​ Digestive system Part 1: digestive tract Oral cavity -​ Mechanical digestion: teeth and tongue -​ Chemical: salivary amylase & saliva Throat -​ Epiglottis; flap that closes during swallowing to protect your trachea -​ Esophagus: hollow muscular tube connecting the mouth to the stomach - within the esophagus are muscle contractions called peristalsis; involuntary contractions in the esophagus pushing the bolus down into the stomach stomach -​ Breaks down food chemically (HCl) and mechanically (churning) -​ Chemical digestion of proteins begins  1.​ sphincters -​ Esophageal sphincters: controls food entering stomach -​ Pyloric sphincter: controls flow of chyme entering into small intestine 2.​ Gastric juices: made of HCl, salts, enzymes, water and mucus -​ HCl activates pepsin (pepsinogen) 3.​ Chyme -​ Thick frothy white liquid produced in stomach -​ Combination of gastric juices and digested food -​ Created by churning 4.​ Mucus -​ Protects the lining of the stomach from gastric juices 5.​ rugae -​ Gastric folds allowing stomach to expand 6.​ 3 muscle layers (inner, middle and outer) -​ Responsible for peristalsis, churning and mixing of food Small intestine -​ Completion of chemical digestion of macromolecules -​ Absorption of nutrients into bloodstream 1.​ Duodenum -​ Most chemical digestion occurs here -​ receives secretions from the pancreas via the pancreatic duct and the liver and gallbladder via the common bile duct -​ Walls are lined with villi increase surface area and absorption 2.​ jejunum -​ Completion of chemical digestion-secretes digestive enzymes -​ Most absorption occurs here 3.​ ileum -​ Absorbs nutrients and pushes the remaining undigested material into colon The small intestine contain structures that increase surface area -​ Plica: folds in SI -​ Villi: finger like projections covering plica and is lined with blood vessels (capillaries) and lacteals (lymphatic vessels) to absorb nutrients -​ Microvilli: hair like structures covering villi (brush border) The small intestine absorbs… 1.​ Monosaccharides; directly into the bloodstream via capillaries in the villi  -​ Monosaccharides are transported to the liver where converted into glucose (used by the body cells for energy) and excess glucose is converted into glycogen 2.​ Amino acids (proteins) -​ Absorbed directly into bloodstream via capillaries -​ Used by body cells to make enzymes and other proteins 3.​ Glycerol and fatty acids (fats) -​ Absorbed through the lacteals and eventually transferred to the bloodstream -​ Once absorbed, they are reassembled to form triglycerides until they reach the blood and then broken down back into glycerol and fatty acids. -​ Provide energy to the cells. 4.​ Minerals, vitamins and water -​ Most absorption of vitamins and minerals in the small intestine via capillaries -​ Water, vitamin K+ and ions will be absorbed by large intestine Large intestine 6 distinct regions -​ Absorption of water  -​ Production of solid food waste for elimination -​ Production of vitamin K via E coli fermentation The large intestine contains billions of aerobic bacteria that synthesize vitamin K and several B vitamins from solid waste -​ Probiotic bacteria: good bacteria that inhibit the growth of disease-causing bacteria and found in fermented foods like yogurt, kefir, and kimchi -​ 2 types; lactobacilli and bifidobacteria Elimination of waste is controlled by 2 anal sphincter 1.​ Internal sphincter: involuntary 2.​ External sphincter: voluntary Accessory organs 1.​ Liver -​ 4 lobes of unequal size -​ Largest internal organ -​ 4 main function - production of bile - detoxification - storage of glucose as glycogen - amino acid production 2.​ gallbladder -​ Stores bile to secrete into the duodenum via common bile duct -​ Bile aids in the mechanical/physical digestion of fats/lipids. -​ Bile Emulsifies large fat droplets into smaller fat droplets this creates a greater surface area to be exposed for lipases to chemically digest the fats/lipids. -​ Bile NOT an enzyme. 3.​ Pancreas; primary functions include -​ Manufacturing digestive enzymes for the breakdown of macromolecules -​ Ex. Proteases e.g., trypsin- digest proteins -​ Lipases e.g., pancreatic lipase- digests fats -​ Carbohydrases e.g., pancreatic amylase and -​ disaccharides- digest carbohydrates -​ Secreting bicarbonate ions (HCO3) which aid in the neutralization of the acidic chyme entering the duodenum. pH rises to approximately 8 (slightly basic) -​ Manufacturing the hormones insulin and glucagon, which regulate blood sugar levels. Hemoglobin and leukocyte Hemoglobin levels: ​ Low hemoglobin (anemia) can indicate conditions like iron deficiency, chronic disease, or blood loss, leading to fatigue, weakness, and pallor. ​ High hemoglobin can be a sign of dehydration, lung disease, or a rare condition called polycythemia vera, which causes excessive red blood cell production, leading to thicker blood and potential clotting issues. Leukocyte levels: ​ Low leukocyte count (leukopenia) may suggest an underlying infection, bone marrow problems, or conditions like HIV/AIDS, leading to a weakened immune system and increased risk of infection. ​ High leukocyte count (leukocytosis) can indicate an ongoing infection, inflammation, stress, or certain cancers like leukemia, signaling that the body is responding to these issues with increased white blood cell production. Enzymes & macromolecules Protein -​ Pepsin (in stomach) -​ Trypsin (small intestine) -​ These are called proteases 1.​ Pepsin: active form of pepsinogen, found in the stomach and works best in a acidic pH (pH of 2), breaks down proteins into smaller peptides 2.​ Trypsin: found on brush border of small intestine, works best in a neutral pH and breaks down remaining peptide bonds (from protein) into amino acids 3.​ Amylase: pancreatic and salivary, found in the pancreas and salvia, works best in a neutral pH (pH 7) and breaks down carbohydrates (starch into simple sugars) -​ Salivary amylase begins chemical digestion by breaking down starch into simple sugars 4.​ Lipase: breaks down fats in food, works best in a neutral pH, found in the pancreas, mouth and stomach -​ Lipase works with bile to break down fats as fats are insoluble in water Macromolecules are molecules that the body needs in large amounts -​ Carbohydrates→ monosaccharides (smallest form) -​ Lipids→ glycerol and fatty acids -​ Proteins → amino acids Carbohydrates: -​ Example: Starch (found in bread and pasta). -​ Digestion: Broken down into simple sugars (like glucose) by amylase in the mouth and small intestine. Proteins: -​ Example: Meat or eggs. -​ Digestion: Broken down into amino acids by pepsin in the stomach and trypsin in the small intestine. Lipids (Fats): -​ Example: Butter or oils. -​ Digestion: Broken down into fatty acids and glycerol by lipase in the small intestine, with help from bile. Where Digestion Begins: -​ Carbohydrates digestion begins in the mouth with salivary amylase. -​ Protein digestion starts in the stomach with pepsin. -​ Fat digestion begins in the small intestine with bile and lipase. Mechanical digestion 1.​ churning -​ Occurs in the stomach -​ When food passes through the esophageal sphincter and into the stomach, the stomachs muscular wall churns, mixing the food and the gastric juices together to form chyme 2.​ peristalsis -​ Involuntary contractions within the esophagus, pushing food down into the stomach -​  2 Circulatory system 1.​ The heart The heart contains 4 chamber ( 2 upper, 2 lower) Vena cava: collects deoxygenated blood from all over the body -​ Superior vena cava: top of the body -​ Inferior vena cava: bottom of the body Right atrium: -​ Receives deoxygenated blood -​ Sends blood to right ventricle Tricuspid valve: -​ Ensures blood flow is the correct way and prevents backflow Right ventricle: -​ Pumps deoxygenated blood to blood through the pulmonary arteries after passing the pulmonary valve Lungs: -​ Diffusion occurs through capillaries -​ CO2 exhaled O2 inhaled and goes back to the heart through pulmonary veins Left atrium -​ Pumps oxygenated blood to the left ventricle Mitral valve -​ Ensures blood flow is the correct way and prevents backflow Left ventricle -​ Pumps blood through the aortic valve, into the aorta Aorta -​ Pumps blood to the rest of the body -​ branches off into smaller arteries (carotid, brachial, coronary) -​ The coronary artery provides blood to the heart muscle -​ 2.​ The blood Made up of plasma, RBC and leukocytes (WBC) -​ Regulates Temperature by controlling heat loss by changing the volume of blood flow near the surface -​ Transportation of essential nutrients, gases and other chemicals -​ Also transports waste products Plasma: -​ Clear yellowish liquid -​ 92% water dissolves and transports substances -​ 7% dissolved blood proteins antibodies, maintain fluid balance -​ 1% ion nerves function, maintain fluid balance White blood cells:  -​ Fight infection (can increase to more than 2% volume when you're sick) -​ 5 main types -​ Phagocytosis: engulfing pathogens -​ Platelets: clot blood Red blood cells: -​ Specialized for oxygen -​ No nucleus but millions of molecules of hemoglobin 3.​ Blood vessels Arteries and Veins -​ Capillaries -​ smallest of the blood vessels -​ connect arterioles to venules -​ exchange of water, oxygen, carbon dioxide and other -​ nutrients between blood and tissues happens here -​ capillary walls are 1 cell thick -​ diameter is only big enough to let cells through single file Pulmonary circuit: deoxygenated blood Systemic circuit: oxygenated blood 3 respiratory system 1. Nose/Nasal Cavity: -​ Function: Filters, moistens, and warms air as it is inhaled. The cilia and mucus help trap dust and pathogens. 2. Pharynx (Throat): -​ Function: A passageway for air from the nasal cavity to the larynx. It also serves as a pathway for food to the esophagus. 3. Larynx (Voice Box): -​ Function: Contains the vocal cords and is involved in sound production. It also acts as a passageway for air to the trachea. 4. Trachea (Windpipe): -​ Function: A rigid tube that carries air from the larynx to the bronchi. It is lined with cilia that help expel trapped particles. 5. Bronchi: -​ Function: The trachea divides into the left and right bronchi, which direct air into the left and right lungs. 6. Bronchioles:  -​ Function: Smaller branches of the bronchi that lead air deeper into the lungs. 7. Alveoli: -​ Function: Tiny air sacs where gas exchange occurs. Oxygen moves into the blood, and carbon dioxide moves from the blood to the alveoli to be exhaled. 8. Lungs: -​ Function: House the bronchi, bronchioles, and alveoli. The lungs are the primary site of gas exchange, where oxygen is absorbed into the blood, and carbon dioxide is removed. 9. Diaphragm: -​ Function: A muscle beneath the lungs that contracts and relaxes to help draw air into the lungs and expel air out (breathing). 10. intercostal Muscles: -​ Function: Muscles located between the ribs. They help with breathing by expanding and contracting the chest cavity: ○​ External intercostal muscles: Contract to lift the ribs during inhalation, increasing chest volume. ○​ Internal intercostal muscles: Contract to pull the ribs downward during exhalation, decreasing chest volume. How air travels through the respiratory system Upper respiratory tract -​ Air enters and is warmed, moistened and cleansed in the nasal passage -​ Thin turbinate bones project into the nasal passage and increase the surface area -​ Ciliated cells move trapped particles into the nose or mouth so they can be expelled by coughing or sneezing -​ The warm air passes into the pharynx (throat) -​ At the base of the pharynx is the entrance to the trachea (windpipe) -​ Glottis is the opening of the trachea, and can be closed by the epiglottis Lower respiratory tract -​ Bronchi branch from the trachea; one enters into each lung -​ Further branch into a network of tubules called bronchioles; each bronchiole ends in a tiny sac called an alveoli -​ Surrounding each alveoli are capillaries -​ The walls of both are only one cell thick to allow for easy diffusion of oxygen and carbon dioxide Inhalation nose→pharynx→larynx→trachea→bronchi→bronchioles→alveoli -​ Pressure decreases volume increases -​ Diaphragm contracts Exhalation alveoli→bronchioles→bronchi→trachea→larynx→pharynx→nose -​ Pressure increases and volume decreases -​ Diaphragm relaxes Gas exchange and inhalation/exhalation 1.​ inspiration -​ External intercostal muscles and diaphragm contract -​ Ribs move up and out and diaphragm moves down -​ Chest volume increases, lung pressure decreases and air pulled into lungs 2.​ expiration/ expiration -​ Muscles relax and the ribs move down and in -​ Diaphragm moves up and the chest volume decreases -​ Lung air pressure increases and air is pushed out of lungs Gas exchange occurs in the lungs, specifically in the alveoli, tiny air sacs where oxygen and carbon dioxide are exchanged between the air and the blood. The two structures involved are: 1.​ Alveoli – where oxygen from inhaled air diffuses into the blood, and carbon dioxide from the blood diffuses into the alveolar air to be exhaled. 2.​ Capillaries – small blood vessels surrounding the alveoli, where the exchange of gases takes place. Oxygen moves into red blood cells, and carbon dioxide is carried from the blood into the alveoli. ↓ Structures controlling pressure and volume in the lungs Diaphragm: -​ When the diaphragm contracts, it moves downward, increasing the volume of the chest and decreasing the pressure in the lungs (relative to atmospheric pressure), causing air to flow into the lungs (inhalation). -​ When the diaphragm relaxes, it moves upward, decreasing the volume of the chest and increasing the pressure in the lungs, pushing air out (exhalation). Intercostal muscles: -​ The external intercostal muscles contract during inhalation, lifting the ribs upward and outward, which further increases the volume of the chest and lowers the pressure, allowing air to enter the lungs.  -​ The internal intercostal muscles contract during forced exhalation, pulling the ribs downward and inward, reducing the chest volume and increasing the pressure to force air out. Capillaries -​ One cell thick -​ Connects arterioles to venules -​ Smallest of the blood vessels -​ Diameter only big enough to let cells pass through in a single file -​ Exchange of oxygen, water and carbon dioxide Valves of the heart 1.​ Tricuspid Valve (right atrioventricular valve): -​ Function: Controls blood flow from the right atrium to the right ventricle. -​ If it fails: Blood could flow backward into the atrium (regurgitation), leading to inefficient heart function and possible fluid buildup. 2.​ Pulmonary Valve (right semilunar valve): -​ Function: Controls blood flow from the right ventricle into the pulmonary artery, sending blood to the lungs for oxygenation. -​ If it fails: Blood could flow backward into the right ventricle, reducing oxygenated blood flow to the lungs and impairing circulation. 3.​ Mitral Valve/bicuspid valve (left atrioventricular valve): -​ Function: Regulates blood flow from the left atrium to the left ventricle. -​ If it fails: Blood could flow backward into the left atrium (mitral regurgitation), leading to reduced blood supply to the body and pulmonary congestion. 4.​ Aortic Valve (left semilunar valve): -​ Function: Controls blood flow from the left ventricle into the aorta, sending oxygen-rich blood to the body. -​ If it fails: Blood could flow backward into the left ventricle (aortic regurgitation), reducing effective blood circulation to the body and increasing cardiac workload.  UNIT 5 BIODIVERSITY *Understand how to create and read dichotomous keys and spider keys Different types of biodiversity Biodiversity means a variety of living organisms 1.​ Genetic diversity -​ Sum of all genes present in a population -​ Species: members of the same population that look similar can breed with each other to produce viable offspring -​ Each organism has its own DNA making every organism unique -​ Allows for species of populations to adapt faster eg antibiotic resistance 2.​ Species diversity -​ Variety of species in a given area -​ Allows for the environment to survive droughts to survive droughts and plagues, disease ect. 3.​ Ecosystem diversity -​ Diverse range of habitats, the organism that live in those habitats, and the relationship that connects them -​ Any change in ecosystem will have some effect on entire ecosystem but the greater the diversity the better able it is to stay balanced Variation in a population Resilience: Genetic variation increases a population's ability to adapt to changing environments or challenges (like diseases, climate change, or resource scarcity). With diverse traits, some individuals are more likely to survive and reproduce under new conditions, ensuring the population can persist over time. Fitness: The fitness of a population refers to how well individuals can survive and reproduce in their environment. Higher variation can enhance the population's overall fitness because it increases the likelihood that some individuals will possess traits that make them better suited to their environment. This leads to improved survival and reproduction rates, helping the population thrive. Different types of Archaea 1.​ Thermophiles: survive in high temps 2.​ Methanogens: survive in high levels of gas 3.​ Halophiles: survive in high salt concentration 4.​ Acidophiles: survive in low pH environments \  Archaea Bacteria extremophiles Mesophiles unicellular unicellular prokaryotic Prokaryotic Glycan cell wall or no cell wall Peptidoglycan cell wall Reproduce via binary fission Reproduce via binary fission Genetic variability via conjugation Genetic variability via conjugation Does Not normally cause human Cause human disease disease Autotrophic or heterotrophic Autotrophic or heterotrophic Contain unusual lipids in their cell Gram staining membrane Aerobic and anaerobic Aerobic or anaerobic Prokaryotic vs Eukaryotic Prokaryotes Eukaryotes ↓ ↓ Bacteria and plants, fungi, Archaea animals, protists Prokaryotes Difference Eukaryotes smaller Size Bigger Unicellular Number of cells Multicellular No nucleus Nucleus Nucleus asexually reproduction Both (mainly sexually) Circular genetic material Type of genetic material Linear genetic material -​ DNA organized into chromosomes  None (lacks organelles like Membrane bound Defined (has organelles mitochondria and organelles like mitochondria) chloroplast) Bacteria and archaea examples Protist, fungi, animals, plants Shape of bacteria Bacilli(bacillus) =rod shaped cocci(coccus)= round spirilla=spiral diplo=paired strepto=chain staphylo=clump Ex. if you got an image where it is rod shaped and climbed it would be staphylobacilius staphylococci, diplobacilli, streptococcus Gram stain Gram positive: thick peptidoglycan and stains purple Gram negative: thin peptidoglycan and stains pink Lysogenic vs Lytic The lytic cell -​ Host cell breaks open, spreading viruses to other cells -​ Short incubation period The lysogenic cycle: -​ Virus integrates its DNA into the host genome and doesn’t spread to other cells unless host cell is under pressure -​ Long incubation period Bacteriophage 2 parts 1.​ head -​ Capsid -​ Nucleic acid (DNA and RNA) 2.​ tail -​ Sheath -​ Plug -​ Tail fibres Locomotion of protists 1.​ Cillia -​ Hair like projections that work together in a coordinated rhythm to make the protists move through water  -​ Cover the surface of protists -​ Ex. paramecium 2.​ Flagella -​ Long whip like structures that help propel (through waving or rotating) them towards food -​ Ex. euglena 3.​ Pseudopod -​ Temporary, fixable extensions of the cell membrane and cytoplasm that allows cells to move and capture food by engulfing -​ Ex. amoeba Taxonomy -​ The genus and species are used in binomial nomenclature -​ Species name consist of a genus and species with the genus being capitalized and species name without a capital and the full name is either italicized or underlined Ex. homo sapiens (humans) 1.​ Domain: eukarya 2.​ Kingdom: animalia 3.​ Phylum: chordata 4.​ Class: mammalia 5.​ Order: primates 6.​ Family: hominidae 7.​ Genus: homo 8.​ Species: sapiens Species that are closely related will share more ranks on the taxonomic hierarchy and use physical evidence such as.. 1.​ DNA: the more similar the DNA sequence, the more closely related they are 2.​ Morphological features: comparing bone structure and body shape can indicate evolutionary relationships 3.​ Fossil evidence: show how species evolved over time 4.​ Embryonic development: Similarities in the early stages of development can suggest that species share a common origin. 5.​ Phylogenetic trees: diagram that shows the evolutionary relationships between different species or organisms. Types of protists 1.​ Animal like (protozoa) -​ Heterotrophs -​ Use cilia, flagella and pseudopods for movement -​ Typically unicellular -​ Eat prokaryotic + protists →cercozoans amoeba →ciliates paramecium 2.​ Plant like (algae) -​ Autotrophic -​ Can be both uni and multicellular -​ Contain chlorophyll for photosynthesis -​ →diatoms -​ →euglenoids (autotroph in sun, heterotroph in dark) -​ →dinoflagellate (2 flagella) 3.​ Fungus like -​ Spore production -​ Heterotrophs -​ Uni or multicellular -​ →Slime mould (myxomycota) -​ →Water mould (amoeboid) *euglena; type of euglenoid, are both heterotrophs and autotrophs as they create their own food in the sun and consume food in the dark Antibiotic resistance -​ Random mutations in bacterial DNA can create resistance to antibiotics. These mutations may allow bacteria to survive exposure to the drug. -​ When an antibiotic is used, it kills susceptible bacteria but leaves behind those with resistance. These resistant bacteria multiply and spread. - Endosymbiotic theory The endosymbiotic theory suggests that mitochondria and chloroplasts used to be free-living prokaryotes but were eventually engulfed by other larger cells. But instead of being digested, the remained intact and continued functioning Evidence -​ Mitochondria and chloroplasts possess their own DNA. The DNA is circular and without proteins as is the DNA in bacteria  -​ Ribosomes of mitochondria and chloroplasts resemble those of bacteria and cyanobacteria (similar size and nucleotide sequence) -​ Mitochondria and chloroplast reproduce independently of their eukaryotic host cell by a process similar to binary fission -​ Both have 2 membranes 1.​ Inner lipid bilayer membrane: bacterial cell plasma membrane 2.​ Outer lipid bilayer: came from cell that engulfed it SWOT 1.​ fragmentation Strengths Weaknesses Opportunities Threats -​ Job -​ Pollution -​ Road -​ Leads to habitat opportunities -​ Animals have signs/fines isolation -​ urbanization difficulty -​ Habitat -​ Road interacting restoration construction -​ Habitat loss separates ecosystem -​ Less breeding so less diversity 2.​ Plastic pollution Strengths Weaknesses Opportunities Threats -​ Easily -​ Animals may -​ Social -​ Economic accessible eat involvement cost of having -​ Affordable and -​ Animals may -​ Biodegradable to clean up reliable choke and substitutes -​ Reliant on -​ Used for die from it -​ Ocean cleanup plastic human needs -​ Animals may technologies -​ microplastics get trapped in plastic  3.​ Oil spills Strengths Weaknesses Opportunities Threats -​ Employment rates -​ Habitat -​ Renewable -​ Air pollution -​ Advanced drilling disruption energy -​ change/rising technologies -​ Pollution -​ Social media temps -​ High energy -​ Climate (education) -​ Water density fuel change -​ Different pollution (gasoline) methods of -​ Destroys transportation habitats if oil leaks