Biology grade 11
Genetic Processes
DNA Structure
Nucleotide
A nucleotide is the repeating unit that makes up DNA, made up of deoxyribose sugars, a phosphate group, and one of four nitrogenous bases.
Complementary Base Pairing
Pairing of a nitrogenous base of one strand of DNA with a nitrogenous base of another strand, adenine (A) pairs with thymine (T), and guanine (G) with cytosine (C).
Structure of DNA
DNA is made of pentose sugar, a phosphate group, and one of four nitrogenous bases.
The proportion of adenine (A), thymine (T), guanine (G), and cytosine (C) are in equal proportions, i.e. 1(A):1(T), 1(G):1(C).
DNA has the shape of a corkscrew or a helix.
Chromosomes
Haploids vs Diploids
Haploids are cells with one set of chromosomes (n =23 chromosomes) (contains 23 chromosomes)
Diploids are cells with two sets of chromosomes, with each parent contributing a chromosome to each pair (2n = 46 chromosomes) (contains 46 chromosomes, 23 pairs)
Autosomes and Sex Chromosomes (Sex Determination)
Autosomes are non-sex related chromosomes, 23 pairs, 22 of these pairs are autosomes.
Sex chromosomes are a set of chromosomes that are x and y, and are from sperm (contains x or y) and egg cells (only x).
Sex is determined by which sperm cell reaches the egg, sperm x and egg produce a girl, and sperm y and egg produce a boy.
Homologous Chromosomes
A pair of chromosomes that contains the male and female chromosomes with alleles that carry the same gene type, found in the same loci. Chromosomes are inherited maternally and fraternally.
Cell Division
Mitosis
In asexual reproduction, the mother cell becomes two daughter cells. It starts with prophase, then metaphase, anaphase, and then telophase. Cytokinesis is the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells and happens after PMAT.
Meiosis
Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (sperm and egg cells). In the first division of meiosis, the number of cells doubles but the chromosome number halves. In Meiosis II, division is like mitosis; the number of chromosomes is not reduced.
Comparison of Mitosis vs Meiosis
Mitosis produces two genetically identical “daughter” cells from a single “parent” cell, whereas meiosis produces cells that are genetically unique from the parent and contain only half as much DNA
Karyotypes
A karyotype is an individual's complete set of chromosomes, sorted and arranged according to size.
Abnormal Meiosis
Non-Disjunction
Non-disjunction is when chromosomes fail to separate. This results in the daughter cells having abnormal amounts of chromosomes. The reason this happens is because homologous chromosomes could not move to polar opposite ends of the cell which results in the splitting of the cell to produce unequal amounts of chromosomes. Non-disjunction cells have chromosomes with 22 or 24 chromosomes.
Trisomy
An abnormality in which there are 3 homologous chromosomes in place of a homologous pair.
Monosomy
An abnormality that involves a single chromosome in replacement of a homologous pair of chromosomes.
Notation: Syndrome, total # of chromosomes, sex chromosomes, +/- and #
Downs Syndrome 47, XX/XY, +21
Turner Syndrome: 45, XO
Klinefelter Syndrome: 47, XXY
Supermale Syndrome: 47, XYY
Patau Syndrome: 47, XY, + 13
Edward Syndrome: 47, XX, + 18
Symptoms of Chromosomal Diseases
Down Syndrome
A flattened face, especially the bridge of the nose.
Almond-shaped eyes that slant up.
A short neck.
Small ears.
A tongue that tends to stick out of the mouth.
Tiny white spots on the iris (colored part) of the eye.
Small hands and feet.
A single line across the palm (palmar crease)
Turner Syndrome
A particularly short, wide neck (webbed neck)
A broad chest and widely spaced nipples.
Arms that turn out slightly at the elbows.
A low hairline.
Teeth problems.
A large number of moles.
Small, spoon-shaped nails.
Shorter 4th finger or toe.
Klinefelter Syndrome
A taller, less muscular body.
Broader hips and longer legs and arms.
Larger breasts (a condition called gynecomastia)
Weaker bones.
A lower energy level.
Smaller penis and testicles.
Supermale Syndrome
Spoken language and processing of spoken words are more difficult
Coordination problems
Weaker muscles
Hand tremors
Behavioral problems.
taller than average height
Low muscle tone, or muscle weakness (called hypotonia)
Very curved pinky finger (called clinodactyly)
Widely spaced eyes (called hypertelorism)
Patau Syndrome
Cleft lip or cleft palate.
Difficulty gaining weight.
Extra fingers or toes (polydactyly).
Ears forming low on the head.
Growth abnormalities in the arms and legs.
Low muscle tone (hypotonia).
Small head and lower jaw.
Very small, close together, or underdeveloped eyes.
Edward Syndrome
Low birth weight.
Small head and jaw.
An unusual-looking face and head.
Unusual hands and feet with overlapping fingers and webbed toes.
Problems with feeding, breathing, seeing and hearing.
Heredity
Gregor Mendel
Gregor Mendel was a biologist who experimented with peas, discovering genetics.
Crosses
A di-hybrid cross is a cross that involves two genes, each consisting of heterozygous alleles.
Monohybrid cross involves only one gene, using parents with pure genes, for example, black hair and no hair at all.
Laws
The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring. One copy of each gene is passed on because the genes separate with gametes during gamete formation.
The law of independent assortment states that if genes are located in separate chromosomes, they will be inherited independently of one another (gametes carry only one allele for a gene), this happens during metaphase 1 when the homologous pairs line up.
Alleles, Genotypes, Phenotypes
Alleles are one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Phenotype refers to an individual's observable traits, such as height, eye color, and blood type. A person's phenotype is determined by both their genomic makeup (genotype) and environmental factors. Dominant genes are prioritized over recessive genes.
Genotype refers to the genetic makeup of an organism; in other words, it describes an organism's complete set of genes. For example, dominant hairless, recessive haired, Yy.
Complete Dominance
Complete dominance is a condition where the dominant allele completely masks the effect of the recessive allele. The dominant trait will determine phenotype no matter the recessive gene.
Co-Dominance
Codominance is a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual. Codominance shows the two separate genes while incomplete dominance is a mixture between two genes (If incomplete dominance, colors of the “dominant trait” mix rather than show separation). Both genes influence the phenotype.
Sex Linked
Sex-linked describes an allele that is found on one of the sex chromosomes, X or Y and when passed down is expressed.
Autosomal inheritance is the inheritance of alleles located on autosomal chromosomes (non-sex) chromosomes. If an allele is found on an autosomal pair, that is autosomal inheritance. Autosomal inheritance affects both males and females equally.
X-linked is a phenotypic expression of an allele that is found on an x chromosome.
Y-linked is a phenotypic expression of an allele that is found on a y chromosome.
Some alleles that cause genetic disorders are found on the sex chromosomes. Since the allele with the disorder is on the x chromosomes and is recessive, this makes this sex-linked inheritance, or more specifically, x-linked. A mother with a recessive allele will pass on that allele because the y chromosome of the male will be unable to mask it. For daughters, the only way to have it show is if both x chromosomes carry the recessive gene. If the daughter has the recessive gene but doesn’t show it, it makes her a potential carrier for the issue. Y-linked disorders pass from father to son. There are fewer Y-linked diseases because the y chromosome carries little genetic information.
For Punnet Square for sex-linked, the male is XY and the female is XX.
Multi-Trait
Multi-trait inheritance (dihybrid cross) is when more than one set of genes is passed down. When two parents are hybrid for different traits (color and size), they can produce babies that have inherited the hybrid traits.
Test Cross
A test cross is used to determine the genotype of an individual expressing a dominant trait. It is used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous. Always performed with an unknown genotype and homozygous recessive genotype. Typically used on fast reproducing species. It is not used often anymore as advances in molecular biology techniques allow testing for specific alleles within genotypes of an organism directly.
DIAGRAMS
Animals - Structure and Function
Cellular Biology
Organelles:
Membrane: the membrane is used as a shield, protecting the cell and its insides from unwanted pests. Membranes are made of a bilayer (double layer) of fat molecules called phospholipids, as well as proteins and carbohydrates.
Nucleus: the nucleus is the control center of the cell and directs all the cell’s activities. Genetic information is stored within the nucleus in the form of chromosomes which contain DNA, a substance that carries the coded instructions for all cell activities.
Ribosomes: ribosomes are organelles that are used to produce proteins through protein synthesis. Some ribosomes are found in the cytoplasm, but most are attached to the endoplasmic reticulum.
Endoplasmic Reticulum: the endoplasmic reticulum is a series of folded membranes that move materials (proteins) around in a cell. Rough ER has ribosomes attached to it, smooth ER does not have ribosomes attached. Products of the ER are enclosed membrane-bound structures called vesicles. These vesicles are used by another part of the cell.
The Golgi Apparatus: the Golgi apparatus is composed of lots of flat tubes that look like they are stacked on top of each other. This organelle chemically changes the fats and proteins the ER produces and packages them inside the vesicles.
Lysosomes: lysosomes are vesicles. Lysosomes are cell organelles which are only found in animal cells. They may be used to digest food particles, as well as destroy potentially dangerous microorganisms like bacteria and viruses. When the cell gets old, lysosomes break open and decompose the cell. This process is called apoptosis
Mitochondria: a mitochondrion is a circular or rod-shaped organelle that floats freely in the cytosol. Sometimes called the “power plant” of the cell, their job is to make energy. This energy is used by the cell. It comes from the burning of glucose, a sugar, through a process called cellular respiration. Cells where cellular respiration has to happen very fast, such as muscle and liver cells, have many mitochondria.
Vacuoles: Vacuoles are large sacs filled with a watery solution containing dissolved sugars, minerals, and proteins. Usually found within plants
Chloroplasts: Chloroplasts are responsible for photosynthesis, which is a process by which the cell converts carbon dioxide and water into food for the cell (glucose sugar). Chloroplasts also have two membranes, arranged in connected compartments called thylakoids. The membranes of thylakoids contain a green pigment called chlorophyll. This pigment is responsible for the green color of plants and is also responsible for the start of photosynthesis.
Hierarchy of Cells to Organisms
Organelle -> Cells -> Tissues -> Organs -> Organ systems -> Organisms
Plant vs. Animal
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Eukaryotic vs. Prokaryotic
EUKARYOTES
Nucleus
Bigger
More complex (greater number of organelles)
Makeup plants, animals, fungi, some protists
Reproduces sexually and asexually (meiosis and mitosis)
Membrane - bound organelles
PROKARYOTES
No nucleus
Smaller
Less complex (less organelles overall, no organelles really)
Make up eubacteria, archaebacteria, protists (some)
Reproduces sexually and asexually (Conjugation and binary fission)
Circulatory System
System Types
Closed Circulatory: the blood is enclosed in the vessels and the heart while circulating. The blood travels through arteries and veins and carries important molecules throughout the body. Animals have a closed circulatory system, blood is cycled through the body.
Open Circulatory: It is primarily found in invertebrates. Here, the blood flows freely through cavities since there are no vessels to conduct the blood.
Blood Components
Blood is made of plasma, red blood cells, white blood cells, and platelets. 55% plasma, 45% blood cells, and less than 1% white blood cells as well as platelets.
Structures and Function of Heart Components
Pulmonary Artery/Vein: pulmonary arteries carry oxygen-poor blood from your heart to your lungs. As well as carrying carbon dioxide back towards the lungs. Pulmonary veins are blood vessels that carry oxygen-rich blood from your lungs to your heart.
Right Atrium/Right Ventricle: the right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs.
Left Atrium/Left Ventricle: the left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the oxygen-rich blood to the body.
Aorta: The aorta is the main artery that carries blood away from your heart to the rest of your body. The blood leaves the heart through the aortic valve.
Vena Cava (inferior + superior): The superior vena cava and inferior vena cava are very large veins that bring deoxygenated blood to your heart to get oxygen. Your inferior vena cava, your body's largest vein, carries oxygen-depleted blood back to your heart from the lower part of your body (below your diaphragm)
Sinoatrial Node: The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.
Atrioventricular Node: The AV (atrioventricular) node is primarily an electrical gatekeeper between the atria and ventricles and introduces a delay between atrial and ventricular excitation, allowing for efficient ventricular filling.
Veins: veins are similar to arteries but - because they transport blood at a lower pressure - they are not as strong as arteries. Veins receive blood from the capillaries after the exchange of O2 and CO2 has taken place. Valves are located inside the veins - the valves act like gates only allowing traffic to move in one direction. Vein valves are necessary to keep blood flowing toward the heart.
Arteries: Arteries need to withstand a great deal of pressure, as the blood from the heart is being pumped right into them. Arteries can withstand this pressure because the walls of the arteries are thick. Arteries branch from the aorta, which then branch off into arterioles.
Capillaries: Capillaries are only one epithelial cell thick - they are so thin that blood cells can only pass through them in a sing le file line. The exchange of O2 and CO2 takes place through the thin capillary wall. The tissue releases its waste products - like CO2 - which pass through the wall and into the red blood cells that are still in the capillaries.
Pathway of Blood
1. Deoxygenated blood is brought to the heart through the superior vena cava (from the upper body) and the inferior vena cava (from the lower body)
2. The superior and inferior vena cavas deliver the blood into the right atrium
3. The tricuspid valve will open and allow the deoxygenated blood from the right atrium to flow into the right ventricle
4. Once the tricuspid valve is closed, the pulmonary (semilunar) valve will open and the deoxygenated blood will be pumped through the pulmonary arteries (right and left) to the lungs to get reoxygenated
5. The blood returns from the lungs (now oxygenated) through the pulmonary veins (right and left) and is delivered into the left atrium
6. The bicuspid valve will open and allow the oxygenated blood from the left atrium to flow into the left ventricle
7. Once the bicuspid valve is closed, the aortic (semilunar) valve will open and the oxygenated blood will be pumped through the aorta to be brought to the rest of the body
8. Eventually the blood will make its way around the body, becoming deoxygenated along the way, and will be brought back to the heart via the superior and inferior vena cavas (and the cycle will start again)
Cardiac output
Cardiac output is the product of heart rate (HR) and stroke volume (SV) and is measured in liters per minute. HR is most commonly defined as the number of times the heart beats in one minute.
Heart Sounds
Pulse is the valves in your veins opening and closing.
Cardiovascular Health (Arteriosclerosis and Bypass Surgery)
Arteriosclerosis is a type of vascular disease where the blood vessels carrying oxygen away from the heart (arteries) become damaged from factors such as high cholesterol, high blood pressure, diabetes, and certain genetic influences.
Bypass surgery creates a new path for blood to flow to the heart. A healthy blood vessel from another part of the body is used to redirect blood around a blocked area of an artery. Usually, the blood vessel is taken from an artery in the chest, called the internal mammary artery.
Respiratory System
Structures and Functions of the Respiratory System Components
Nasal Cavity: Filters, warms, and moistens air. Mucus lining and cilia (tiny hairs) help prevent foreign objects from entering. Hollow spaces with turbinates to warm and moisten air.
Oral Cavity: Warms and moistens air. Acts as an alternate pathway for gas exchange.
Larynx: 3 main functions: A passageway for air; a valve to close off the air passage from the digestive system; a voice box. Inside is a flexible membrane that vibrates when air passes through it.
Right Lung: Site of alveoli. Exchange oxygen and carbon dioxide. Enclosed within a special membrane (like a balloon inside a bag) called a pleural membrane.
Right Bronchus: Passage of air to lungs. Contains branching increases surface area and mucus filters foreign particles.
Diaphragm: Muscular structure that acts as the floor of the chest (separates the thoracic cavity from the abdomen). Increases and decreases the volume of the chest cavity by forcing air into and out of the lungs. Is a very thin muscular structure.
Pharynx: Chamber connecting oral and nasal cavities. Food goes down the esophagus and air passes through the trachea. Connects to the surrounding region.
Trachea: Passage of air that branches off into the right and left bronchi. Made up of protective “c” rings of cartilage to ensure it stays open and to protect the esophagus which is just behind it.
Left Bronchus: Passage of air to lungs. Has a sharp bend compared to the right lung due to the presence of the heart and the major blood vessels under it.
Bronchiole: Further branching from bronchus to each alveolus. Each bronchus divides and subdivides into smaller and smaller branches.
Pathway of Oxygen
Oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. This process is called diffusion. In the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood then goes to the heart, which pumps it to the body.
Mechanisms of Breathing
Intercostal muscles (between the ribs, kind of like webbing) and the diaphragm control breathing. The movement of these muscles determines whether we are inhaling (drawing air into the lungs) or exhaling (pushing air out of the lungs). This form of gas exchange relies on differences in pressure between the air in the atmosphere and the air in the lungs. To better understand how pressure changes in the thoracic cavity, the relationship between pressure and volume must be understood. Pressure is inversely proportional to volume, as pressure goes up, volume goes down, and vice versa.
Process of Exhalation:
The diaphragm relaxes and moves up.
The external intercostal muscles relax and move down and in.
This decreases the volume in the thoracic cavity.
The change in volume causes an increase in pressure.
The increase in pressure causes air from the lungs to be pushed out into the atmosphere (out of the lungs).
Process of Inhalation:
The diaphragm contracts and moves down.
The external intercostal muscles contract and move the ribs up and out.
This increases the volume in the thoracic cavity.
The change in volume causes a decrease in pressure.
The decrease in pressure causes air from the atmosphere to rush into the lungs.
Lung Capacity & Spirometer Readings
Regulation of Breathing
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Conditions Affecting the Lungs
Smoking: Smoking can cause lung disease by damaging your airways and the small air sacs (alveoli) found in your lungs. Lung diseases caused by smoking include COPD, which includes emphysema and chronic bronchitis. Cigarette smoking causes most cases of lung cancer. Treatment includes just not smoking 🤷
Asthma: asthma is a chronic lung disease affecting people of all ages. It is caused by inflammation and muscle tightening around the airways, which makes it harder to breathe. Treatment involves inhalers, which are devices that let you breathe in medicine, are the main treatment.
Effect of Partial Pressures on Gas Exchange and Body Responses
A greater partial pressure of carbon dioxide in the alveoli causes the bronchioles to increase their diameter as will a decreased level of oxygen in the blood supply, allowing carbon dioxide to be exhaled from the body at a greater rate. In high altitudes, an increase in heart rate and a decrease in stroke volume also occur. During acclimatization over a few days to weeks, the body produces more red blood cells to counteract the lower oxygen saturation in blood in high altitudes.
Interaction of Respiratory and Circulatory Systems
The respiratory system brings in oxygen, and the circulatory transports oxygen around the body and brings back waste for the respiratory system to remove (waste as in CO2).
Digestive System
Structures/Organs and Functions of the Digestive System Components
Oral Cavity: Beginning or digestion, chemical and physical, contains teeth, uvula, tongue, and salivary glands. Acts as a gateway (bouncer and security for the digestive system). Secretes amylase to start the breakdown of starches (basic sugars). Two functions include ingestion and digestion.
Esophagus: A passageway for food from the oral cavity to the stomach. Lined with muscle tissue that rhythmically pulses (peristalsis) food down to the cardiac sphincter.
Stomach: “J” shaped muscular and mucus-lined organ that helps with both chemical and mechanical breakdown. Secretes hydrochloric acid (HCl[aq]). HCL is produced by parietal cells. Chief cells in the stomach produce pepsinogen, which stops the stomach from dissolving the stomach.
Small Intestine: High surface area with finger-like projections called villi. A high density of capillaries which engorge with blood to absorb all the nutrients from food.
Large Intestine: No chemical digestion, Re-absorption of water, and synthesis of vitamins B12 and K which cannot be obtained elsewhere.
Rectum: Muscular tube which acts as the passageway for the anus.
Anus: A sphincter (ring of muscle which acts as a valve to allow things through it) That opens and closes to allow expulsion of waste.
Liver: Over 900 functions. Filters and detoxifies nutrient-rich blood which is coming from the small intestine after absorption. Produces bile and secretes enzymes for digestion.
Gall Bladder: Stores bile from the liver.
Pancreas: Secretes enzymes and hormones, particularly insulin.
Appendix: No known digestive purpose. May store good bacteria. Helps with lymphatic system.
Macromolecules
Macromolecules are organic compounds, referring to their composition, specifically made with carbon and hydrogen, designating them as organic. Hydrocarbons are compounds containing ONLY carbon and hydrogen molecules.
Cells create new cellular structures by combining smaller organic molecules. Molecules created are proteins, lipids, nucleic acids, and carbohydrates.
Carbohydrates: Carbs are used for short and long-term energy storage. Contain molecules of carbon, hydrogen, and oxygen in rations of 1:2:1, CH2O. The three types of carbohydrates are monosaccharides, being the most simple and one we can taste, disaccharides, being more complex, allowing us to only taste a certain few, and polysaccharides, being the most complex, humans are not able to taste these (fully), a saccharide is a sugar. monosaccharides contain 3 to 7 carbon atoms and include glucose, fructose, and galactose. The synthesis of these sugars is called dehydration synthesis.
Monosaccharides that form long chains are called polysaccharides, which include, starch (energy storage for plants), glycogen (energy storage in animal and muscle tissue), and cellulose (the main component of cell walls in plants)
Lipids: Lipids are fats, used for insulation, long-term energy storage, hormone production, organ cushioning, and building cell membranes. Lipid as fat stores/contains 2.25x more energy than carbs. 1g of fat = 9 calories, 1g of carbs = 4 calories. A fat molecule is made with glycerol and three fatty acid molecules. Glycerol is an alcohol (OH, hydroxide group), when it joins the three fatty acid molecules, it becomes triglyceride, which is hydrophobic as it is a non-polar molecule where water is polar. Chains vary in length, with no double bonds in the hydrocarbon section structure, which is called saturated fat. If a double bond exists, it is monounsaturated. If many double bonds exist, it is polyunsaturated.
Protein: Acts as an enzyme to aid in chemical reactions (a catalyst?), Transport materials across the cell membrane or to different parts of the organism, acts as hormones, a key component in hair, nails, muscle, fleshy bits, etc. More complex and diverse compared to the previous two. Proteins contain nitrogen, the other macro to contain this is nucleic acids. The smallest unit of a protein is amino acids. Amino acids are made up of carboxylic acids. Humans require 20 different amino acids, only differing in atoms of the “R” group. Peptide bonds are amino acid chains. A chain of amino polypeptides, Polypeptide must coil into a helix, or fold into a pleated sheet, with continuous twists or folds to form a protein (Amino acid -> peptide -> polypeptide -> protein). The shape of the protein determines reactibility. Extreme heat, cold, or pH unfolds protein and makes it lose shape, lose reactability, and become denatured.
Definitions
Monomer: A monomer is a single organic compound that can be used to make a polymer.
Dimer: 2 monomers bonded together.
Polymer: A chain consisting of multiple monomers.
Polymerization: The process of chaining monomers together to form a polymer.
Path of Food Along the System
Mouth (chemical digestion from salivary glands through the use of amylase, mechanical from chewing) --> Esophagus (mechanical digestion from the pulsing of the esophagus pushing food down) --> Stomach (chemical digestion, hydrochloric acid) --> Small Intestine (chemical, breaks down and absorbs remaining compounds) --> Large Intestine (bile is produced at some point and breaks down fat)
Lactose, lactase, and Lactose Intolerance
Lactase is the enzyme found in the small intestine, which dissolves lactose (milk sugars). They change the milk sugar into absorbable compounds – glucose and galactose. Too little of an enzyme produced in your small intestine (lactase) is usually responsible for lactose intolerance. You can have low levels of lactase and still be able to digest milk products. But if your levels are too low you become lactose intolerant, leading to symptoms after you eat or drink dairy.
Diseases/Conditions Affecting the Digestive System
Stomach acid is strong enough to kill most bacteria that enter the stomach. However, one species of bacteria, Helicobacter pylori (commonly known as H. pylori), can survive by secreting acid-neutralizing enzymes and by burrowing through the mucosa. These bacteria prevent mucus-producing cells from producing enough mucus to protect the stomach lining. When the lining is exposed to the strong stomach acid, an open sore, called an ulcer, can develop. Ulcers can bleed and can be painful. Bleeding ulcers can be dangerous because the bacteria can enter the bloodstream and produce an infection throughout the body. H. pylori may be transmitted through food or water, but the bacteria have also been found in the saliva of people with ulcers. H. pylori is usually successfully eliminated with antibiotics. Proton pump inhibitors (PPIs) can be used to treat ulcers. Omeprazole, pantoprazole, and lansoprazole are the PPIs most commonly used to treat stomach ulcers
Diarrhea is when your stools are loose and watery. You may also need to go to the bathroom more often.
Diversity of Living Things Exam Topics
Diversity
Genetic Diversity
Individuals of a sexually reproducing species inherit unique combinations of genetic information from their parents. This produces genetic diversity. Examples of human genetic diversity are differences in hair, skin, and eye color, as well as in facial features and adult height.
Diversity of Interactions
The important activities and processes of one species may depend entirely on another species for success. Species support each other and they also contribute to the stability and productivity of their ecosystems. The term species diversity describes both the variety of species in an ecosystem and the number of individuals within each of those species.
Commensalism: When interacting, one species benefits and the other gets neither a benefit nor a non-benefit.
Mutualism: When interacting, both species get a benefit.
Parasitism: When interacting, one species gets a benefit and the other gets harmed.
Diversity of Habitats
The range of physical sizes, shapes, and distribution of the individuals, as well as habitats and communities in an ecosystem, are together referred to as structural diversity. Structural diversity creates microhabitats with a variety of abiotic conditions For example, oceans, and rainforests have abundant structural diversity compared to an even-aged tree plantation
Structural Diversity
The range of different physical landscapes within a habitat; the more diversity, the more opportunities for different organisms to live.
Importance of Diversity & Threats to Diversity
Importance: all species depend on each other. The loss of biodiversity affects humans in many ways: threatens our food supply when entire species and plant varieties are lost. Eliminates sources of natural medicines and potential new medicines. Has a significant economic impact on tourism and forestry when accompanied by habitat destruction. Has the potential to cause serious disruptions in biogeochemical cycles, including normal carbon uptake by natural ecosystems.
Threats: human actions are resulting in a rapid loss of natural habitats due to agriculture, forestry, urban expansion, the introduction of invasive species, over-harvesting of wild populations, and serious air and water pollution
Classification
Carl Linnaeus considered species to be district types of living things that could be grouped into categories called genera (singular: genus) according to shared characteristics.
Taxonomic System
Kingdom
Phylum
Class
Order
Family
Genus
Species
Binomial Nomenclature
Binomial Nomenclature is how they name things Humans are called Homo Sapiens as Homo is the genus and Sapiens in the species.
Dichotomous Keys
Used to categorize and separate species from each other and look at similarities and differences.
Six Kingdoms - Characteristics of All
Eukaryotic versus Prokaryotic cells
Viruses
Characteristics
All consist of RNA or DNA molecules surrounded by a capsid which is made up of protein. Some viruses are surrounded by an envelope. Viruses only become active when their genetic material enters and controls a living cell. Considered to be non-living and small. No cytoplasm cannot grow or reproduce on its own. Do not create waste.
Infectious Cycles
Cladograms
Antibiotics
Prokaryotes and fungi are often in direct competition with each other for food and resources, and they produce antibiotic substances as a form of chemical warfare.
Antibiotics make it possible to kill bacteria where they are unwanted.
Antibiotics may not be so effective in the future as the overuse of antibiotics can cause bacteria to adapt and become resistant so antibiotics are no longer effective.
Antibiotics can kill both good and bad bacteria.
Evolution
The Evidence for Evolution
Homologous structures are similar physical features in organisms that share a common ancestor, but the features serve completely different functions. The bones in human forearms are of similar structure to the bones of doglegs.
Analogous structures are features of different species that are similar in function but not necessarily in structure and that do not derive from a common ancestral feature. Bird wings and bat wings
Embryonic evidence refers to examining the embryos of animals. Vestigial structures such as tails or gills in humans can be found in embryos early during their development. Vestigial structures are features of an organism that are considered to have lost much or all of their original function through evolution.
Natural Selection
Definition
Natural selection is the process of adaptation to the environment. Some individuals will carry more ideal traits, meaning that the ones with the ideal traits will survive while the unideal dwindles out.
Types of Selection
Directional selection is a mode of negative natural selection in which an extreme phenotype is favored over other phenotypes. For example, the length of giraffe necks may be affected by directional selection.
Stabilizing selection is a form of natural selection where individuals with moderate or average phenotypes are more fit. Instead of having the smallest or biggest neck, stabilizing selection chooses the one right in between.
Disruptive selection is a type of natural selection that selects against the average individual in a population. The makeup of this type of population would show phenotypes of both extremes but have very few individuals in the middle.
Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with and compete with members of the same sex for access to members of the opposite sex.
Adaptations & Role of the Environment/Niches
Adaptations are ways animals develop to deal with changes in their environment. Specific niches of different species have different adaptations.
Artificial Selection and Sexual Selection
Purpose
The natural selection comes from the preference of one sex for certain characteristics in individuals of the other sex. The purpose is to produce offspring with the best or most desirable traits. Females of peacocks will probably choose the male with the biggest tail.
Sexual Dimorphism
Males and females will have drastic differences in color, shape, size, etc.
Behavioral Displays and Male-versus-Male Competition
Display behavior is used for courtship between two animals and to signal to the female that a viable male is ready to mate. Males will fight other males for dominance of a group/territory, or to impress females i.e. bullfighting.
Factors that Change Allele Frequencies
Mutations
Mutations are changes in the DNA sequence that cause abnormalities within a person. Someone who has any of the syndromes mentioned in the genetics unit is considered to have a mutation, a fairly severe one at that.
Speciation
Pre-zygotic and Post-zygotic Reproductive Isolating Mechanisms
Spatial isolation, temporal isolation, mechanical isolation, gametic isolation, and behavioral isolation. Spatial isolation is a type of prezygotic barrier in which different species are reproductively isolated by location, leading to divergent evolution. Temporal isolation is a type of prezygotic barrier in which different species are reproductively isolated by different mating seasons. Mechanical isolation is a physical incompatibility between the reproductive organs of two organisms. Gametic isolation is a type of prezygotic barrier where the gametes come into contact, but no fertilization takes place. Behavioral isolation is when species are reproductively isolated from others due to differences in behavior.
Hybrid sterility, low hybrid viability, and zygote mortality. Hybrid sterility refers to a hybrid not being able to fertilize an egg properly. Low hybrid viability means that although babies are made, the chance of them surviving is low. Zygote mortality means an egg is fertilized but does not last long.
Patterns of Evolution
Adaptive Radiation
A rapid increase in the number of species with a common ancestor, characterized by great ecological and morphological diversity.
Divergent Evolution
The process by which interbreeding species diverged into two or more evolutionary groups. It means that these groups of species used to be similar and related.
Convergent Evolution
The process whereby distantly related organisms independently evolve similar traits to adapt to similar necessities.
Coevolution
Coevolution occurs when species evolve together. Coevolution often happens in species that have symbiotic relationships. Examples include flowering plants and their pollinators.
Plant Anatomy, Growth, and Function
Monocots vs. Dicots
Monocots have one cotyledon within their seed, dicots have two cotyledons. Cotyledons refers to the number of leaves within the seed when it sprouts (also provides energy for growing plant). Monocots have fibrous roots while dicots have a tap root (tuber). Monocots have parallel leaf veins while dicots have networking veins. Monocots have scattered vascular stem bundles, dicots have a ring bundle.
Plant Tissue
Dermal
Dermal tissue refers to the plant epidermis, the outer layer of tissue that surrounds the primary body of vascular plants. This includes the roots, stems, leaves, flowers, fruits, and seeds. The dermal layer does not contain chloroplasts and is typically composed of a single layer of tightly packed cells.
Vascular
Composed of xylem and phloem, form continuous systems through the plant body provide transport pathways for water, nutrients, and signaling molecules, and support a plant body against mechanical stresses.
Ground
The main tissue types of the ground tissue system are parenchyma, collenchyma, and sclerenchyma. Parenchyma has thin walls of cellulose, collenchyma has cell walls with thickened areas of additional cellulose. Sclerenchyma cells have lignified cell walls. Ground tissue makes up most of the interior of a plant. It carries out basic metabolic functions and stores food and water.
Meristematic
Meristems in plants are the center of active mitotic cell division where plant growth occurs. These tissues can be found in root tips, shoots, buds, and any place where new growth occurs. Comparable to animal cells.
Xylem and Phloem
The xylem distributes water and dissolved minerals upward through the plant, from the roots to the leaves. The phloem carries food downward from the leaves to the roots. The tension created by transpiration “pulls” water in the plant xylem, drawing the water upward in much the same way that you draw water upward when you suck on a straw. The high turgor pressure forces the movement of phloem sap from source to sink through a process called “bulk flow”.
Transport
A source is a cell with a high concentration of sugars, a sink is the opposite. A source and sink will change as the needs of the plant change. An example is the change in seasons (sugar moving from roots to leaves allows us to capture the sap and produce maple syrup in the spring) or when the fruit is developing (plants move sugars into the fruit to make it sweet and attractive to animals). Translocation is the term used to describe the long-distance movement of substances in the phloem. The Casparian strip helps ensure that substances that enter the vascular cylinder do not leak back into the cortex.
Capillary action, the adhesion properties of water (attraction to the tube) are stronger than the cohesion properties (attraction to each other), forcing water to move upward in a small opening. As water exits the leaf, water in the xylem moves into the unoccupied space because of the cohesion of water molecules.
Seed Structure and Functions
Consisting of three parts, embryo, endosperm, and seed coat. The embryo is a tiny plant that has a root, a stem, and one or more leaves. The endosperm is the nutritive tissue of the seed, often a combination of starch, oil, and protein. The seed coat is used as a layer of protection from external forces and unwanted pests.
The epicotyl extends which allows the embryonic shoot to break through the soil. The hypocotyl extends which pushes the radicle deeper in the soil to form the roots. The radicle is capable of absorbing water from the soil, which is required for the development of the embryonic plant. The plumule forms the shoot of the plant, it is responsible for performing photosynthesis. Cotyledons help supply the nutrition a plant embryo needs to germinate and become established. Testa is the outermost covering of the seed which protects the seeds from external injury and bacterial infection. Tegmen is a second protective layer.
Structures & Functions of Leaves, Stems, and Roots
Functions & Locations of Internal Structures
The layers of a leaf include the cuticle layer, the upper epidermis, the palisade layer, the spongy layer, the lower epidermis, and the stomata. These structures all work together to enable plants to acquire the raw materials needed to carry out photosynthesis. The cuticle is the external shielding, the epidermis protects plants and is used to retain moisture. Stomata regulate gas exchange between the plant and the environment and control water loss by changing the size of the stomatal pore. The palisade layer is for photosynthesis.
The stem of a plant is made of the cortex, cambium, phloem, xylem, pith, and epidermis. The cortex is responsible for the transportation of materials through diffusion and may also be used for the storage of food in the form of starch. The main job of the cambium is to promote the growth of the secondary xylem and phloem. It's located directly between the primary xylem and phloem in a circular layer. The primary function of the pith is to transport nutrients throughout the plant and then store the nutrients within its cells.
Root hairs form the outermost dermal layer alongside the epidermis. Both are thin to maximize the efficiency of diffusion. The endodermis layer has a waxy structure called a Casparian strip, which controls water movement. The next layer is the root cortex, which is made of parenchyma cells. These cells can store carbohydrates in the form of starch. Apical meristems in the root, develop new cells and elongate the root cap. The root cap is a bundle of cells that protect the root itself.
Leaf specializations
Venus flytraps are leaves with modifications that allow for trapping of insects, for nutrients. This applies to Drosera sp., Pinguicula, and pitcher plants. Cactus spines are also specialized leaves.
Asexual Plant Reproduction
Plants can reproduce asexually via many methods. These methods include runners, tubers, leaves, and roots. Since asexual reproduction produces genetically identical clones, these clones may carry the same traits of the mother plant which allows for survival in certain environments. Grafting is an interventional form of asexual reproduction. Grafting involves cutting a young branch from a plant that has desirable characteristics and attaching it to the stem of another plant. Usually, both plants are of the same or closely related species. The branch is called the scion and the plant that provides the stem and root system is called the stock.
Types of Tropisms and Nastic Movements
Phototropism
Phototropism is the ability of the plant to re-orient the shoot growth towards a direction of light source. Phototropism is important to plants as it enhances the ability of plants to optimize their photosynthetic capacity
Gravitropism
Gravitropism is an important plant growth response to the environment that directs shoots upward and roots downward, thereby allowing each organ to reach environments that are adequate for the performance of their primary functions.
Thigmotropism
Thigmotropism is when a plant responds to a movement or touch from another stimulus. This stimulus is known as a contact stimulus. Two types of hormones help a plant respond to a contact stimulus: auxin and ethylene. These hormones can affect the plant's growth and orientation. Vining plants may react to the touch of a tree by sending out roots to cling to said tree.