Grade Eleven Biology NotesBridget Walsh

Unit One (Chapter 4 Genetics)

Genetics- the study of how traits are passed from one generation to the next

Genotype- internally coded, inheritable information, refers to the combination of alleles for a particular trait that is present in an individual

Phenotype- outward appearance or physical manifestation of the trait

Allele- alternate form of a gene located at a particular place on a chromosome

Trait- characteristic

Gene- factor that controls a trait

An organism that is homozygous dominant has the same phenotype as an organism that is heterozygous

If an organism has the dominant phenotype, its genotype is not necessarily known A pedigree illustrates inheritance patterns over several generations, type of flowchart, uses

symbols A dominant trait is always expressed Mendel succeeded in discovering the laws of inheritance when others failed because:

o Chose appropriate organism to study Pea plant

Commercially available Easy to grow, matures quickly Sex organs enclosed in flower=easy to control

o Designed and performed the experiment correctlyo Analyzed data properly

Mendel’s 1st experiment was a monohybrid cross because he was only testing one trait (plant height)

He knew that the short pea plants were purebred because o Short x short =always short plantso Tall x tall = mostly tall some shorto Conclusion: short must be the recessive gene

For his 1st experiment he crossed pure bred tall plants with pure bred short and the first generation was all tall, in the second generation there was a 3:1 ratio of tall to short plants which because Mendel’s famous ratio

Conclusions: o Each parent starts with 2 factors;1 dominant and 1 recessive

o 1 factor comes from each parento Offspring inherits 1 factor from each parent, if dominant is present it will be expressedo Recessive will only be expressed is only recessive factors are present

Law of Segregation- Inherited traits are determined by pairs of “factors” (alleles). These factors separate in the gametes

Pedigrees: the keys to reading them!o If a trait is not expressed in either parent but it is expressed in the children, you know it

is recessiveo If the trait is not expressed in both parents but it is in the children than you know both

parents must be heterozygous for that trait Generations: P F1 F2

o P- parent generationo F1- 1st filial generationo F2-2nd filial generation

Punnet squares are an easy and simple way of determining genotype and phenotype they are used to calculate the probability of inheriting a particular trait

Someone might be interested in genetics to determine how much is heredity and how much is nurture (farmer for example)

Test cross- a dihybrid crossed with the recessive for both traits Autosomal inheritance- the inheritance of traits determined by genes on the autosomal

chromosomes An autosomal dominant disorder occurs when the disease causing allele is dominant and an

individual has one or both copies of the allele An autosomal recessive disorder occurs when the disease causing allele is recessive and an

individual has both copies of the allele Mendel’s 2nd experiment was a dihybrid cross, that is he allowed the F1 generation to self-

pollinate the results represent a phenotypic ratio of 9:3:3:1 Law of Independent Assortment:

o This second law of inheritance states that the inheritance of alleles for one trait does not affect the inheritance of alleles for another trait

Modes of Inheritance (Beyond Mendel’s Law)o Incomplete dominance

Not all traits are purely dominant or recessive, when this occurs the blending of two traits can take place and this is called incomplete dominance

o Co-dominance Both alleles are expressed like a chicken with black and white feathers

o Sex- linked Inheritance Trait located on one of the sex chromosomes (X or Y)

o Multigenic The gene is present in several chromosomes

o Epitasis

The expression of one gene affects the expression of another gene Somatic cell- any cell in our body that is not a sex cell Haploid number is half the diploid number In humans the sex of the child is dependant largely on the father Mode of inheritance for human blood type is codominance and multiple alleles Zygote- fertilized egg Homologous chromosomes are similar not identical The number of chromosome pairs is half the number of chromosomes Alleles do not assort independently if they are linked Diploid advantage

o Refers to gene expression. The advantage lies in the event of genetic damage or mutation. Where only one of the chromosomes is necessary for expression the presence of two can offer a “back up” in the event the other doesn’t function properly. In addition it offers greater potential for survival in the event option “A” is not well suited to the changing environment; if the presence of a “B” option is available it might be the expression that could help. Without diploid chromosomes a genetic strain could die out.

Evolution

Important to note that populations evolve not individuals an individual does not aquire evolutionary changes. Evolution takes place over many generations and is a slow, gradual process. A difference amongst individuals is variation not evolution.

2 organisms belong to the same species if they can reproduce and their offspring are viable Changes within a species result of random DNA mutations = variation Adaptation is a structural, behavioural or physiological process that helps an organism survive

and reproduce in a changing environment The founder effect is a change in gene pool that occurs when a few new individuals start a new

isolated population The bottleneck effect is changes in gene distribution that results from a rapid decrease in

population size Selective pressure- is environmental conditions that select for certain characteristics of

individuals and select against others E.g. forest, taller trees = more sun will reproduce and pass of the alleles to survive conditions. The abundance of alleles for these conditions will increase in the population

Artificial selection- selective pressure exerted by humans on populations in order to improve or modify particular traits

Monoculture- extensive planting of the same varieties of a species over large expanses of land Natural selection- the process by which characteristics of a population change over many

generations as organisms with heritable traits survive and reproduce, passing their traits to offspring

Fossil record- the remains and traces of past life that are found in sedimentary rock; it reveals the history of life on Earth, the kinds of organisms that were alive in the past

Darwin’s Theory (summarized)o Organisms produce more offspring than can survive ergo organisms compete for limited

resourceso Individuals of a population vary extensively and much of this variation is heritableo Individuals that are better suited to local conditions survive to produce more offspringo Processes are slow and gradual

How we classify organisms:o Where and how they liveo Morphologyo DNA similarities

Vestigial structure- a structure that is a reduced version of a structure that was functional in the organism’s ancestors

Biogeography- the study of the past and present geographical distribution of species populations, supports Darwin and Wallace’s theories

Q: Why is it more important if a mutation occurs in a gamete cell?o A: If a mutation occurs in a somatic cell the trait is lost when the individual dies, it does

not greatly affect the population of the species. However when mutations occur in the gamete cells, through meiosis and sexual reproduction the trait can be passed on to the offspring

Q: Explain how the value of variation can change over time and give an exampleo A: Something that proves advantageous now may be a disadvantage as environmental

conditions change. Example: light levels in a forest. If trees are adapted to survive shady conditions and the amount of light increases the trees may not survive.

Q: How will a development that confers a survival advantage contribute to an increase in diversity and an increase in complexity?

o A: survival advantage = increase in reproductive fitness = increase in population size = increase in diversity = competition = complexity

3 people who contributed to Darwin’s theory of evolution:o Charles Lyell, Jean Lamarck and Thomas Malthus contributed very important ideas to

Darwin’s theory of evolution. Lyell proposed that the geological processes operated today at the same rates as in the past. He called this uniformitarianism. He theorized that small subtle changes could occur over a long period of time resulting in substantial change. This idea inspired Darwin to thinking, if the Earth is slowly changing could slow subtle changes occur in species and populations? Lamarck compared species of animals with fossil forms and interpreted a “line of descent” which led to modern species. He noted that an organism’s adaptations to the environment resulted in characteristics that could be inherited by offspring, Darwin accepted these theories and acknowledged Lamarck. Finally Thomas Malthus provided insight on how populations changed. He declared that populations produced more offsping than their environments could support. From this Darwin surmised that individuals with traits that helped them survive in their local environment were more likely to survive and pass these traits to offspring.

Diversity of Life

DNA, Origins of Life, Single Celled Organisms

Considering organisms- factors that are important to considero Matter

How the organic compounds are obtainedo Energy

The energy stored in somewhat macromolecules that are “food” (sugars, amino acids, fatty acids) is “parcelled” (mostly in cellular respiration) into smaller packets of energy stored as ATP (adenine triphosphate)

o ATP/ADP reaction ADP+Pi-> ATP Adnenine diphosphate plus phosphate = adenine triphosphate

o How an organism obtains energy to regenerate ATP is an important classification tool Autotrophs

Obtain energy from inorganic (abiotic) sources; heat, sulphuric acid, light

Heterotrophs Require organic (biotic) sources

Q: Explain the functions of the DNA moleculeo A: DNA has 2 functions

It contains information for the order of amino acids in proteins a gene is a sequence of DNA that contains the info to make one protein

Reproduction, replicating itself What forms a nucleotide?

o A: Each nitrogen base is attached to a sugar, each sugar to a phosphate group to form a single nucleotide. Each nucleotide is named after the base it contains

RNA 3 differences from DNA:o Single stranded and unstableo Contains the sugar ribose instead of deoxyriboseo Does not contain thymine instead contains uracil

DNA replication o Enzyme breaks down hydrogen bonds between nitrogen baseso Double helix “unzips”o Another enzyme moves along each strand attaching nucleotides to each base o Continues until formation of new molecules

Enzymes- control virtually all chemical reactions going on in your body. Enzymes are a specific protein produced by cells. It is these chemical reactions that provide your body with energy

Polypeptides- linked amino acids forming long chains, two or more polypeptides are joined to make a particular protein

How can organisms be so different if their DNA is composed of the same nucleotides? o A: Unique genetic information is determined by the sequence of nucleotides. The closer

the relationship between two organisms the greater their similarities in their DNA sequence

How many amino acids are attached to a single transfer RNA?o A: One!

Transcription- The process of making RNA from DNA occurs in the nucleus Explain why DNA is compared to a zipper

o A: nucleotides are joined together to form long chains. The phosphate group of one nucleotide is joined to the deoxyribose sugar of the adjacent nucleotide. The nitrogen bases stick out like teeth on a zipper while the phosphate group and sugar make the backbone

Purines- nucleotides with a double ring structure (adenine and guanine) Pyrimidines- single ring nucleotides (cytosine and thymine) Translation- the process of assembling a protein from RNA occurs in the cytoplasm Complementary base pairs- nitrogen bases are always paired in the same manner A-T, C-G they

are called complementary base pairs Q: List several observations about biomolecules that are compatible with the ideas of evolution.

o A: The code is universal, there are only 20 amino acids, there are 4 different nucleotides for DNA and 4 for RNA all of this is evidence of a common ancestor

Errors in DNA Replication:o Errors do occur despite an enzyme proofreading, and remember mutations aren’t

always bad Base pair substitutions occur when one base pair is replaced by another e.g. A-T

pair replaced by C-G pair this may alter the outcome of the amino acid or code for STOP causing problems

A frameshift mutation occurs when one or more base pairs are added or deleted, all subsequent codons will be different

Eukaryotic cell Prokaryotic Cell Evolution of the Eukaryotic Cell- endosymbiosis hypothesis where heterotrophic bacteria

became the mitochondria and cyanobacteria became chloroplasts after being taken up by host cells

o Evidence The membranes of chloroplasts and mitochondria are similar to those of living

prokaryotes The ribosomes in chloroplasts and mitochondria are similar to the ribosomes in

prokaryotic cells

Chloroplasts and mitochondria contain a circular chromosome with many gene sequences similar to those in prokaryotic chromosomes

Chloroplasts and mitochondria reproduce by binary fission within a cell The genes in chloroplasts most closely match the genes of modern prokaryotic

cyanobacteria Abiotic Evolution

o Nucleotides, amino acids and other building block macromolecules can form spontaneously when scientists imitate conditions of primordial Earth (hydrogen, methane, carbon dioxide, no oxygen)

o Formation of the polymers DNA proteins and lipids came with the discovery of a catalyst which was primordial clay. When this mineral clay (which would have been abundant 4500 million year ago) is mixed with nucleotides, they form chains similar to DNA and RNA

o Some chains of nucleotides began to replicate due to complementary base pairingo Q: How can proteins be made (primordially) from DNA if protein enzymes are required?

A: discovery of importance = RNA RNA can contain info, replicate and act as a catalyst

o At the same time that this self replicating RNA appeared another phenomena happened, the appearance of phospholipic vesicles reminiscent of cells

Cyanobacteria appeared about 2000 million years ago they do photosynthesis but there are two important factors in this reaction

o Carbon fixation o Production of oxygen (before cyanobacteria oxygen wasn’t produced when carbon

fixation happened) Q: What was the great success of cyanobacteria?

o A: Cyanobacteria is the only thing that is able to absorb N₂ which is the most common gas in our atmosphere making up about 70%. It flourished also in part because it used water which was abundant.

Archea are all anaerobic (they are killed by oxygen) they are most commonly classified by habitat:

o Thermophiles (love heat)o Halophiles (love salt)o Methanogens (produce methane)

Archea and Bacteria (prokaryotic cells)o Both archea and bacteria are prokaryotic cells however the two domains are not the

sameo Their morphology is similar, they are the smallest, simplest and most abundant

organisms on Earth they are classified as bacillus, coccus or spirillum based on shapeo All species of both domains reproduce asexually by binary fission (conjugation does

happen to promote diversity)

o Key difference: archea do not use photosynthesis as a source of metabolic energy while some bacteria can use photosynthesis

o Other differences: there are not known disease causing archea, some archea fix atmospheric carbon dioxide while some bacteria fix nitrogen

o The ribosomes and the RNA polymerase of archea are more similar to the ones in Eukarya than those in bacteria. RNA polymerase is the enzyme required to make RNA from the nucleotides. Bacteria and Eukarya have cell membranes made of the same phospholipids but archea’s phospholipids are different

The Viruso A virus is not considered to be a living thing. It is not a cell and therefore is lacking many

of the cell parts. All viruses contain a protective capsid and a core of DNA or RNAo Since viruses cannot live outside a cell they are considered to be parasitico Viruses can only reproduce in a living cell. The lytic cycle is the reproductive cycle of

most viruseso The virus injects its nucleic acid into a cell and it becomes part of the cells DNA.o After a short time the viral DNA takes control and produces more viral DNA and viruseso The viral DNA will produce an enzyme that allows water to rush in causing the cell to

rupture and newly formed phages can escapeo The lysogenic cycle is the alternate reproductive form, during this the viral DNA basically

just hides out in the cell, however if something happens (immune system stress) it can activate the phage DNA and the virus will enter the lytic cycle

Protistao Protozoans

One celled, heterotrophic protests Contain special vacuoles for digesting food and getting rid of excess water. Classified by how they move

o Fungus like protists Like fungus they produce spores, like protozoa they glide from place to place

and ingest food, like plants they have cellulose cell walls Plasmodial slime moulds

Share characteristics with protozoa, moves by means of psuedopods behave like amoeba

Cellular slime moulds Spend part of their life cycle as independent amoeboids that feed grow

and divide, when food is scarce they band together Water moulds

Live in water, appear fuzzy, grow as mass threads and then envelop an animal or plants absorbing its nutrients (they’re gross)

o Plant like protists Unicellular, aquatic, chlorophyll containing Most important one to know about is Euglenoids

Have both plant and animal characteristics, have chloroplasts but lack a cell wall and swim using a flagella. An eyespot allows them to find light to conduct photosynthesis, they can also absorb nutrients across they’re cell membrane

Fungi

Heterotrophs Hyphae- network of fin filaments, densely packed together Mycelium- loose branching network of hyphae under the soil making the bulk of a fungus Septa- cross walls that divide hyphae into cells, septa are porous allowing cytoplasm to flow

through hyphae from cell to cell Multinucleated structure

o Lack septao Each hyphae appear to be on multinucleated cello Within the hyphae the nuclei can move through the undivided cytoplasmo Boundary of a fungal cell is the cell wall, cell wall made of chitino Chitin is the hard material found in the external skeleton of invertebrates

How fungi feedo Saphrotrophs- organisms that break down and live off dead organic mattero Extracellular digestion- release digestive enzymes that break down large organic

molecules in the substrate into smaller molecules that diffuse into fungus Parasetic Fungi

o Have hyphae call haustoria which can penetrate host cells without immediately killing them

Symbiotic Fungio Benefiting both organismso Mycorrhiza- trees having fungi living close to their roots, relationshipo Hyphae grow around roots, increases absorbtive surface of the plant roots, plant can

take more nutrients fungus maintains air and water flow in the soil around the roots Reproduction

o Fragmentation- simplest asexual way in which pieces of hyphae break off and grow into new mycelium

Classificationo Like plants they have cell walls and grow in the groundo Unlike plants they store food energy as glycogen

Bread Moulds- during asexual reproduction they produce zygospores which are diploid structures that develop after 2 haploid hyphae of opposite types combine and fuse nuclei

Mycelium is made up of 2 typeso Horizontal called stolonso Downward called rhizoids, they secrete the enzymes

To reproduce asexually, bread mould has another form of hyphae that project up from the mycelium called sporangiophores carry sporangia at their ends, asexual spores develop and are released when capsules break open

Basidiocarps- short lived structures called fruiting bodies (look like toadstools) Basidia- club shaped hyphae You can see evidence of hidden mycelium in circles of mushrooms called “fairy rings” the center

of the circle is where the mycelium started growing, expanding outward like the spokes of a wheel to produce basidiocarps at their ends

Lichen- do not form a taxonomic group but are a symbiotic association of alga or cyanobacteria and fungus

Plants

All species of plants are multicellular eukaryotes that live on land and obtain food by photosynthesis

Advantages of Lando Greater availability of lighto More rapid diffusion of CO₂ and O₂ into and out of the organism

Disadvantages of Lando Risk of dehydration

Adaptations to life on lando Protection from drying outo System to transport water and dissolved substances from the outside environment to

cells withino System to support the body of the plant

Vascular vs. Non-Vascular Plantso Vascular tissue- made of cells able to conduct solutions throughout the plant similar to

the circulatory system of animalso Non vascular plants include mosses liverworts and hornwortso Sporophytes- diploid generation of a planto Gametophyte- plant body that produces male and female gametes

Mosseso Absorb most of their water directly through their surface when air is dry mosses become

dry when wet conditions return mosses absorb water quicklyo Very successful and widespreado Most diverse group of plants after angiosporeso Seta- spore bearing capsule grows on the end of a stalko Sporophytes do not contain chlorophyll receive all nourishment from gametophyte

Seedless Vascular Plants (include mosses, liverworts and algae)o Different because they developed vascular systemso Sporophyte generation was dominanto Gametophyte still depended on moisture to carry out sexual reproduction

Xylem- specialized tissue that carries out transportation of water, hollow tubes of non-living cell walls

Phoelum- vascular tissue that transports organic matter made up of living cells Movement of nutrients

o Starch from the roots is broken down chemically to sucrose so it can travel through stem to the leaves, sucrose is further broken down to glucose to provide energy to grow leaves. Leaves produce their own glucose through photosynthesis and once they are producing more glucose than they need that excess glucose is converted to starch grains in the chloroplasts then to sucrose for travel and lastly starch again for storage in the roots.

Gymnosperms- have seeds that are exposed on the surface of cone scales Angiosperms- flowering plants (most plants are angiosperms) The sperm endings^ indicate that they reproduce with seeds Lichen is a fungus and a photosynthetic organism that form a composite The benefit of seeds is that they remain dormant for long periods of time so they can withstand

environmental changes such as cold. They also contain their own food source so germination is easier in a variety of places. They are also not dependant on water to survive.

Stomata- the openings on the bottom of leaves that take in gases like carbon dioxide and oxygen when the stomata is open the plant looses water vapour and dehydrates so a plant would want to have less stomata in a dry area so it does not loose too much moisture

Animals

Vertebrate Chordata (all vertebrates are chrodates)o Sub divided into 2 groups

Agnathans (jawless fish) Gnathostomata (jawed animals)

Evolution of Jawso Jaws enabled animals to grasp and crush food o Jaws allowed animals to eat a wider range of foodo Ingesting food is a key characteristic of animals and jaws gave an advantageo Jaws distinguish anthropods from annelids

Annelids- segmented worms Anthropods- joint legged animals Enchinodermata (starfish)- all marine, radial symmetry, larvae are bilaterally symmetrical later

undergo metamorphosis like chordates the coelum develops in the embryo from an out pocketing of the gut

Embryology is what deduced the phylogenic relationship between echinoderms and chordates Coelum- fluid filled body cavity completely surrounded by mesoderm, allows for development of

complex internal organs Ectoderm, mesoderm and endoderm are body layers (starting from the outside moving in) Cnidarians- jellyfish and sea anemones

Anthropods differences from annelids:o Fewer body segments, tendency for segments in the head and thorax regions to fuse

and become specializedo Hard external cuticle acts as an exoskeleton for muscleso Legs, divided into movable segments connected by jointso Separate muscles organized into groups related to specific body movements (unlike

simple sheets of muscle)o Strongly developed jawso Better developed nervous system and sense organs

Most Choradata are vertebrates however there are invertebrate chordates that are still chordates because at some time they have….

o A dorsal nerve cord, which nerves branch from o A notochord or rod of cartiledge which runs along the dorsal length of the bodyo Gill slits in the pharynx or throat

Classification of Living Thingso Taxons form a hierarchy of groups

Kingdom Phylum Class Order Family Genus Species

o Binomial nomenclature is a system of using a two word name for each species, the first word is the genus and is capitalized, the second word identifies a particular species

Two reasons it’s useful: Gives info about the general characteristics of the animal (the genus) More precise identifier than the common name

Determining Relatednesso Anatomy

Physical characteristics from fossils and bones Biological features that have a common evolutionary origin are said to be

homologouso Evidence from development

Comparisons of early stages of embryonic development can reveal similarities not obvious from adult organisms

o Biochemistry Comparison of protein molecules indicate genetic similarities

o DNA Evidence DNA from 2 organisms is separated into single strands and mixed, the more

complementary base pairs the more related

Can also help determine how long ago a species diverged from one anothero Phylogeny- hypothesis about evolutionary historyo Cladogram- a branching diagram like a phylogenic tree but can be used to test

hypotheses

Internal Systems and Regulation

Circulation

Vascular system- system of fluid tissue that plays a role in transporting nutrients and other materials to the cells of the organism

o Almost all multicellular organisms have a vascular system Most animals also have a circulatory system which is a vascular system in which the progress of

fluid is controlled by muscle movements Most multicellular organisms cannot rely on simple diffusion or active transport to bring

materials to the cells quickly enough to meet their metabolic needs, they require a specialized transport system

These come in two typeso Open transport system

In an open system fluid can slosh back and forth, so its typically slower small animals like insects may have an open system

o Closed transport system Pumped around the body using a network of vessels

The fish has a two chambered heart and complete single circulation The amphibian has a three chambered heart and incomplete double circulation The mammal has a four chambered heart and complete double circulation

o All birds and mammals have 2 atria and 2 ventricles in their heart The route taken by the blood within the heart is called cardiac circulation Heart to lungs and back is pulmonary circulation Heart to everywhere else is systemic circulation The transport vessels are three fold

o Arteries-carry blood out of the heart to the rest of the body, they are more elastico Capillaries- super tiny one cell thicko Veins- carry blood to the heart from the rest of the body, they have valves and use

muscle movements to assist in blood flow Blood is the transport medium

o Red blood cells (44%)o White blood cells (1%)o Plasma (55%)

Iron in hemoglobin in red blood cells allows for pick up of oxygen White blood cells come in many different types two most important fight disease

o Macrophages

Phagocytic cells that digest pathogens, part of the bodies innate immune response

o Lymphocytes Part of the bodies acquired immune response, there are 2 types

B cells o Arises from bone marrow

T cellso Arise from thymus gland

Platelets are another component of blood but are not cells. They play an important role in blood clotting

See page 303 for heart diagrams to be memorized (fun stuff!) SA node also known as pacemaker controls heartbeat Cardiac output = stroke volume x heart rate Highest pressure is systolic pressure occurs when left ventricle contracts Lowest pressure is diastolic pressure happens immediately before another contraction Blood pressure= systolic over diastolic

Digestion

Breaking down food chemically is referred to as digestion See page 338 for digestive system diagram to be memorized The large intestine is actually smaller but it got that name because of its large diameter Peristalsis involves circular and longitudinal muscles contracting to physically break up food in

digestive tract Substrate- a molecule on which an enzyme acts Chemical digestion starts in the mouth where the enzyme amylase breaks down starch Gastrin- hormone that stimulates the digestive enzymes in the stomach Liver- is responsible for producing bile salts from cholesterol, they break up fat globules, also

does detoxification Saliva- has two functions

o Assist in chemical digestiono Lubricate food

Villi- villi are minute, finger-like projections in the small intestine that serve to increase the absorptive surface area

Lacteal vessels- in the villi job is to carry fat particles that are absorbed into the lymphatic system

Ileum- part of the small intestine about 3cm long its function is to absorb nutrients, contains fewer and smaller villi

Respiration

Gas exchange is the taking in of oxygen and release of carbon dioxide Respiratory surface- surface area available for gas exchange, needs three things

o Big enough so it meets the organisms metabolic needso Moist, so gases can dissolveo Thin

Skin respiration- exchange of gases across the skin (worms) Gills- feathery tissue structure that ventilate oxygen containing water over the respiratory

surface where it is diffused for circulation The act of ventilating a respiratory surface with air is called breathing, breathing is controlled by

a part of our brain called the medulla oblongata Spiracles- external pores on an insect, spiracles lead to trachea, spiracles controlled by valves We use 2 muscular structures to control air pressure in our lungs

o Intercostal muscles (associated with the ventral surface of the rib cage)o Diaphragm (muscle layer that separates thoracic cavity from abdominal cavity)

Epiglottis- flap that prevents food from going down the trachea instead of the esophagus Tidal volume- air inhaled/ exhaled with normal breathing Inspiratory reserve volume- additional air that can be taken in Expiratory reserve volume- additional volume that can be forced out Vital capacity- total volume of gas that can be moved in/out of the lungs tidal+ inspiratory+

expiratory = vital capacity Residual volume- amount that always stays in the lungs Counter current flow- arrangement in which two fluids exchange substances as they flow in

opposite directions, maximizes concentration between vessels Bronchi are smaller passageways branching from the trachea Bronchioles are even finer tubes Alveoli are grape like sacs that are always moist and are located at the end on bronchioles this is

where actual exchange of gases takes place Oxygen Pick up and Release factors:

o 2 major factors Oxygen concentration, measured in partial pressure Acidity of the surrounding fluid Explanation: when partial pressure is low the bond that links oxygen to the

heme group weakens. The hemoglobin molecule will tend to release its oxygen. Similarly an increase in acidity influenced by dissolved carbon dioxide, weakens the bond in the same way.

Another factor is temperature, cooler temperatures release oxygen slower See dissociation curve on page 294

Study on your own too! There’s stuff I didn’t go into too much detail and it’s always better when you make your own notes in addition, hope this helped though!