BIOLOGY

FINAL EXAM REVIEW

Modern Biology Chapters:

Protein Synthesis (Chapter 10)Genetics (Chapter 9)

Human Genetics (Chapter 12)Evolution (Chapter 15)

Photosynthesis (Chapter 6)Cellular Respiration (Chapter 7)

Ecology (Chapters 19 – 22)

Protein Synthesis

Review DNA:•Carries genetic information

for the cell•Double Helix structure•Made of repeating nucleotides:– Sugar (deoxyribose)– Phosphate molecule– One of four of the nitrogen bases

A, T, G, C

The Central Dogma of Biology:DNA RNA Protein

DNA Replication:When a DNA molecule replicates, it separates at one end to form a replication fork. Each strand serves as a template for synthesis of a new strand.

Protein Synthesis

RNA:•Carries genetic informationTo the site of protein synthesisSingle Helix structure•Made of repeating nucleotides:– Sugar (ribose)– Phosphate molecule– One of four of the nitrogen bases

A, U, G, C- Three types: mRNA- messenger; tRNA-transfer; rRNA - ribosmal

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

The synthesis of proteins takes two steps: transcription and translation.

Transcription: (happens in the nucleus!)-DNA molecule unwinds exposing the portion of DNA that codes for the protein

-Enzyme, RNA polymerase helps line up nucleotides to create a complementary strand of mRNA. The new strand of mRNA is made according to the rules of base pairing: T – A ; C – G BUT…

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

Transcription:BUT… in RNA Adenine (A) pairs with Uracil (U)

What is the mRNA complement to the DNA sequence TTGCAC?Did you get AACGUG? You are right!

~ Don’t forget that RNA uses the base uracilin place of thymine ~

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

Transcription:

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

Translation: (happens in the cytosol)-the new mRNA strand leaves the nucleus

-mRNA is sent to the cytoplasm, where it bonds with ribosomes, the sites of protein synthesis. Ribosome “Reads” the mRNA one codon at a time.

-A codon = 3 bases (i.e. AUG )

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

Translation: (happens in the cytosol)- tRNA molecules, each associated with specific amino acids, bind to the ribosome in a sequence defined by the mRNA codon. - At its head, tRNA has three nucleotides that make up an anticodon.- An anticodon pairs complementary nitrogenous bases with mRNA.

The Central Dogma of Biology:DNA RNA Protein

Protein SynthesisThe Central Dogma of Biology:

DNA RNA Protein

Codon

Anticodon

Protein Synthesis

Translation: (happens in the cytosol)For example, the codon AUC, will pair with tRNA’s anticodon sequence UAG.

- The ribosome continues to slide down the mRNA, growing the polypeptide chain-Peptide bonds are formed between the amino acids

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis

Translation: (happens in the cytosol)- The process continues until one of the three stop codons is reached-At that point, the protein chain connected to the tRNA is released. Translation is complete.

The Central Dogma of Biology:DNA RNA Protein

Protein Synthesis (Gene Expression )

The process of gene expression/protein synthesis follows a specific order:

1. mRNA transcribe the DNA message2. mRNA leaves the nucleus3. mRNA attach3es to the ribosome4. tRNA translates the mRNA codon5. amino acids are bonded together

(PROTEIN)

MENDELIAN GENETICS

Until the 19th century, scientists believed that traits from the parents would blend in the offspring.For example: a tall father and short mother results in a child of medium height, so eventually all members of a species would look the same.

But in the 1850s, Gregor Mendel, an Austrian Monk crossed different strains of garden peas and analyzed the results. His works laid the foundation for principals of heredity.

Gregor Mendel

MENDELIAN GENETICS

MENDELIAN GENETICSFrom these results, Mendel came up

with three postulates or laws:

1.The Law of Dominant/Recessiveness:Alternative forms of a trait are controlled by different alleles of the gene responsible for that trait.

2. The Law of Segregation:When gametes (haploid reproductive cells) form in diploid individuals, the two alternative alleles for a gene segregate or separate from each other. One goes in one gamete, the other in another…

3. The Law of Independent Assortment:Every gamete has an equal chance of receiving either member of an allele pair. Dominant or recessive traits don’t always get inherited together.

MENDELIAN GENETICS

Some Important Genetics Vocabulary:•Genetics is the study of the heredity of organisms.•A gene is a segment of DNA and is the basic unit of heredity.•An allele is one of two or more alternative forms of a gene.•A recessive gene is one that is phenotypically expressed in the homozygous (must have both recessive alleles - i.e. bb) state but is masked in the presence of a dominant gene.•A dominant gene is one that is expressed phenotypically in heterozygous (Bb) or homozygous (BB) individual; one that is shown or present•Phenotype- physical appearance of an organism – based on genotype

MENDELIAN GENETICS

Some Important Genetics Vocabulary:•Heterozygous - a genotype in which the organism carries different/unlike alleles for a single trait (i.e. Bb, Tt, Ee) – Sometimes referred to as a hybrid or carrier.•Homozygous - a genotype in which the organism carries the same alleles for a single trait (i.e. bb, tt, ee, BB)

MENDELIAN GENETICS

Some Important Genetics Vocabulary:Incomplete dominance: Sometimes heterozygous genotypes result in phenotypes that do not precisely resemble one parent.•Phenotype is intermediate or “blending” between the two parental phenotypes (incomplete dominance).

MENDELIAN GENETICS

Some Important Genetics Vocabulary:•Codominance: Sometimes heterozygous genotypes result in phenotypes in which both parental phenotypes can be identified or expressed in the offspring.

GENETICSSex chromosomes: chromosomes that dictate the sex of certain organisms (the remaining chromosomes are called autosomes).

In humans, there are two sex chromosomes, X and Y.Males possess one each of X and Y chromosomes.Females possess two X chromosomes.

Sex-linked inheritance: In humans, a male expresses all traits unique to the X chromosome he inherits from his mother. Males are afflicted with X-linked disorders because there is no counterpart on the Y chromosome to express the functional allele..

GENETICS

Karyotype: Simply a picture of a person's chromosomes.

You can obtain geneticinformation about theindividual:•Boy or Girl?•Number and appearanceof chromosomes.Based on this karyotype, this individual is a BOY.

REMEMBER: BOY= XYGIRL = XX

GENETICS

Pedigrees: A pedigree is a diagram that shows the occurrence and phenotypes of a particular gene and its ancestors from one generation to the next. Commonly used to trace inheritance of x-linked traits, such as hemophilia, through generations.

MUTATIONSA Mutation is a sudden change in the genetic material of an organism.

**Sometimes harmful to the organism…~ A dark furry rabbit in the tundra… ~

**Sometimes beneficial when it gives an organism an advantage to survive and reproduce

For example: ducks webbed feet – the advantage - They can paddle quicker and more effectively through the water.

MUTATIONS

TYPES:Point mutations: Mutations that affect single genes through a base-pair substitution, deletion, or insertion.•Point mutations may have no effect, may improve or damage the protein.

MUTATIONS

Chromosomal mutations: Mutations that affect an entire organism.

•Nondisjunction: An error in chromosomal distribution during meiosis, which results in gameteswith an abnormal chromosome count.

•Polyploidy: A mutation in which gametes contain more than two full sets of chromosomes.

MUTATIONSMutations can also occur on individual chromosomes. These include:•Deletion: A chromosomal fragment gets detached during cell division;•Duplication: That same fragment joins its homologous chromosome;•Inversion: That fragment gets reinserted backward; or•Translocation: That fragment gets attached to a non homologous chromosome.

The effects of chromosomal mutation are often fatal or can result in genetic disease but in rare cases may improve an organism’s fitness.

DNA TECHNOLOGY

DNA technology uses Deoxyribonucleic acid (DNA), to unlock some of the mysteries behind human behavior, disease, evolution, and aging.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Some DNA-based technologies include: Cloning PCR Recombinant DNA technology DNA fingerprinting Gene therapy DNA microarray technology DNA profiling

DNA TECHNOLOGY

For example: Cloning - Clones are organisms that are exact

genetic copies. Every single bit of their DNA is identical. Clones can happen naturally—identical twins are just one of many examples. Or they can be made in the lab.

DNA TECHNOLOGY When scientists clone a

gene, they isolate and make exact copies of just one of an organism's genes. Cloning a gene usually involves copying the DNA sequence of that gene into a smaller, more easily manipulated piece of DNA, such as a plasmid. This process, called recombinant gene technology, makes it easier to study the function of the individual gene in the laboratory.

DNA TECHNOLOGY

For example: Recombinant Gene Technology: recombinant DNA

technology is the joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations. This is of great value to science, medicine, agriculture, and

industry.

EVOLUTION

Evolution is the process by which species change gradually over time.

Evolution has led to the diversification of all living organisms from a common ancestor, which is described by Charles Darwin as "endless forms most beautiful and most wonderful“. 

EVOLUTION

Jean-Baptiste Lamarck (1744 to 1829) was a French naturalist who is now infamous for the “giraffes stretched their necks to reach for food and therefore gave birth to offspring with long necks” example of evolution.

Lamark’s Theory of Inheritance of Acquired Characteristics, was eventually disproved

EVOLUTION

Charles Darwin, often referred to as “The Father of Modern Evolutionary Thought” , traveled for five years aboard the ship, the H.M.S. Beagle. He studied fossils that formed in different times. Older and newer rock layers held fossils that were similar but changed over time.

EVOLUTION

He also studied plants and animals of the world, especially those that inhabited the Galapagos Islands. He formed hypotheses about how and why populations change. Lots of evidence supports his ideas, so they are now called Scientific theories.

EVOLUTION

A Scientific theory is not just a guess. Scientific theories are well-substantiated explanations of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation.

EVOLUTION

Darwin’s ideas about evolution and natural selection can be summed up in two theories:(1) DESCENT WITH MODIFICATION

(2) MODIFICATION BYNATURAL SELECTION

EVOLUTION

The theory of descent with modification says that newer species are related to and descended from earlier species.

EVOLUTION

The theory of Natutral Selection explains that organisms that are best suited to their environment are more likely to survive and reproduce.

EVOLUTION

Therefore, individuals with certain traits more successfully survive and

reproduce, passing those traits to the next generation.

 

 

EVOLUTION

Artificial selection:

Humans intentionally breed animals to enhance specific traits.

 

Evidence of EVOLUTION

Fossil EvidenceHomologous and Analogous StructuresEmbryologySimilarities in DNA/Proteins

Evidence of EVOLUTION

Fossil Evidence: The fossil record contains

many well-documented examples of the evolution from one species into another, as well as the origin of new physical features.

Evidence from the fossil record is unique, because it provides a time perspective for understanding the evolution of life on Earth.

Evidence of Evolution

Homologous Structures– Similar features that originated in a

shared ancestor.– Different function but structurally

similar (internally).• Example: penguin wing, alligator leg, bat

wing, human arm---internal structure is similar, look different, different functions.

Result from: common ancestry - show they are related.

Analogous Structures• Identical functions, different

structure (internally).– Example: butterfly wings and bird

wings…fly eye and human eye.

Results from: Similar environments (natural selection) – does not show the species are related.

Embryo Development– Similarities in early stages of embryonic

development (conception to birth) among a variety of different species.

– Suggest a common ancestor.

Similarities in DNA– The more closely related two organisms

are, the more similar the DNA sequences.

Energy for Life Processes

• All organisms need energy to survive– Primary source of energy is the sun.

• Energy from the sun is in the form of light energy.

• Energy in food is in the form of chemical energy.

• Energy is the ability to do work… • Work for a cell includes growth & repair,

active transport across cell membranes, reproduction, synthesis of cellular products, etc.

Energy for Life Processes

How do organisms get this energy from the sun?

–PHOTOSYNTHESIS-process used by plants to convert energy from the sun to food (glucose).–Cellular RESPIRATION-process that releases energy in food (glucose) to make energy (ATP).

Energy for Life Processes

Autotrophic – “self-feeding”

• Autotrophs or producers convert sunlight, CO2, and H2O into glucose (their food).– This process is called “PHOTOSYNTHESIS”

• Plants, algae, and blue-green bacteria, some prokaryotes, are producers or autotrophs .

Autotrophs

Plants

Algae & some bacteria

Energy for Life Processes

• Producers make food for themselves and for heterotrophs or consumers that cannot make food for themselves

Heterotrophic – “other-feeding”

• Animals (including humans) represent heterotrophic organisms.

• Since they cannot make their own food, humans and other heterotrophs must get their complex organic compounds (“energy”) by eating plants or other organisms.

Animals and Fungi are heterotrophs!!

Once you eat something, the food gets broken down into ‘nutrients’, or smaller molecules the cells can use.

The bonds that hold these molecules together contain energy.

Photosynthesis & Respiration

Cells “absorb” broken food pieces (macromolecules such as protein, nucleic acid, carbohydrates, lipids). In the form of monomers ( building blocks, such as amino acids, glucose & fructose, nucleotides and some smaller pieces of lipids.).

• Cellular respiration is the process that turns food into ATP, a form of energy that our cells can use.

Photosynthesis & Respiration

Photosynthesis & Respiration

• Only autotrophs are capable of photosynthesis

• Both autotrophs & heterotrophs perform cellular respiration to release energy for cellular processess.

Biochemical Pathways• In photosynthesis, CO2(carbon dioxide)

and H2O (water) are combined to form C6H12O6 (glucose) & O2 (oxygen)6CO2+ 6H2O + Sun’s energy --> 6O2 + C6H12O6

Biochemical Pathways

• In cellular respiration, O2 (oxygen) is used to burn C6H12O6 (glucose) & release CO2 (carbon dioxide) , H2O (water) and energy.

• Usable energy produced in cellular respiration is stored in the chemical bonds of the molecule adenosine triphosphate or ATP

ATP = Adenosine TriPhosphate

The energy is harnessed in the phosphate bonds of an ATP molecule

Photosynthesis & Respiration

Photosynthesis

Cellular Respiration

PHOTOSYNTHESIS

A series of chemical reactions (light & dark

reactions and the Calvin Cycle) where autotrophs capture light energy to make food (glucose).

Chemical Formula:6CO2 + 6H2O + sunlight C6H12O6 + 6O2•Carbon Dioxide water sunlight glucose and oxygen

Leaves: Photosynthetic Factories

• Photosynthesis requires the green pigment chlorophyll.

• The chemical reactions of photosynthesis occur within the chlorophyll-containing organelles called chloroplasts.

• These are found inside cells in plant leaves and stems.

Chloroplasts - membrane bound organelles found in plant and algae cells that absorb light during photosynthesis

They contain:1. the light absorbing pigments2. enzymes for photosynthesis

Light Absorption in Chloroplasts

Light Absorption in Chloroplasts

• Photosynthetic cells may have thousands of chloroplasts

• Chloroplasts are double membrane organelles with the an inner membrane folded into disc-shaped sacs called thylakoids

Light Absorption in Chloroplasts

• Thylakoids, containing chlorophyll and other accessory pigments, are in stacks called granum (grana, plural)

• Grana are connected to each other & surrounded by a gel-like material called stroma

• Light-capturing pigments are found in the grana.

Light Absorption in Chloroplasts

Light Absorption in Chloroplasts

How do chloroplasts absorb light??

LIGHT:

Light travels as waves & packets called photons Wavelength of light is the distance between 2

consecutive peaks or troughs

Light Absorption in Chloroplasts

Sunlight or white light is made of different wavelengths or colors carrying different amounts of energy.

A prism separates white light into 7 colors (red, orange, yellow, green, blue, indigo, & violet)

ROY G BIV

These colors are called the visible spectrum

Light Absorption in Chloroplasts

The visible spectrum:

Each color in a rainbow corresponds to a different wavelength of electromagnetic spectrum.

Light Absorption in Chloroplasts

When light strikes an object, it is absorbed, transmitted, or reflected

When all colors are absorbed, the object appears black

When all colors are reflected, the object appears white

If only one color is reflected (green), the object appears that color (e.g. Chlorophyll)

Thylakoids contain a variety of pigments –molecules that absorbs light - (green, red, orange, yellow...)

Chlorophyll is themost commonpigment in plants & photosynthetic algae

Chlorophyll absorbsonly red, blue, & violet light. Which color does it reflect?

Light Absorption and Pigments

Accessory pigments trap wavelengths of light that can not be absorbed by chlorophyll - help capture more light energy

• Carotenoids – reflect orange, yellow, and brown and absorbs green and blue

• Phycobilins – reflect violet & blue and absorb orange, brown and green

Light Absorption and Pigments

Photosynthesis is not a simple one step reaction but a biochemical pathway involving many steps.

This complex reaction can be broken down into two reactions:

1. light dependent (Photosystem I & II, Electron Transport Chain)2. light independent or dark reactions (The Calvin Cycle)

Overview of Photosynthesis

Overview of Photosynthesis

Sunlight

CarbonDioxide CO2

Water H2O

Oxygen O2

Leaves: Photosynthetic Factories

REMEMBER:This all-important photosynthetic reaction can be summarized by the following chemical equation:

6CO2 + 6H2O + energy (sun) C6H12O6 + 6O2

• Some scientists consider this process of photosynthesis the single most important chemical reaction that occurs on Earth.

• Why?

Science Fact•Some scientists have a theory about the first cells that appeared on earth about 3.5 billion years ago.

•Early cells had to survive in a harsh environment. ..

•Why do you think photosynthesis might have helped different life forms to appear on Earth?

THINK OXYGEN!!!

•In most organisms, two things are needed for cells to get energy: food and oxygen.

•The process by which cells release energy from food is called cellular respiration.

•Cellular respiration is carried out by every cell in both plants and animals and is essential for life.

CELLULAR RESPIRATION

After you eat an apple, your cells are ready to use that stored chemical energy, but

how does this happen?

The release of energy occurs in a series ofenzyme-controlled small steps:

• The energy stored in glucose is convertedinto a usable form, the energy source of all cells, adenosine triphosphate, or ATP. • Cells use the energy from to perform many functions, such as obtaining materials and eliminating wastes.

• Cellular respiration is basically the opposite of the process of photosynthesis.

• Instead of being produced in the cells, the energy-rich glucose molecules are taken apart to release their stored energy.

• Cellular respiration can be summarized by the following chemical equation:

C6H12O6 + O2 ATP (energy) + H2O +CO2

Sugar + Oxygen ATP (energy) + Water + Carbon dioxide

ATP P P P ADP P P

P

+Energy

ATP --> ADP + P + Energy

Bond is Broken

Partiallychargedbattery

Fullychargedbattery

How do you get energy from ATP?

The “Mighty” Mitochondria

Energy Producing

POWER HOUSE!!

Site of C

ellular

Respiratio

n!!

Science Fact

An active cell requires about two million molecules of ATP per second to perform

its life functions.

Cellular respiration is like burning fossil fuels – they both break down organic

compounds to release energy and CO2

Science Fact

A steady supply of ATP is so critical for life that a poison which attacks any of the proteins used in ATP production kills the organism in minutes. Certain cyanide compounds, for example, are poisonous because they bind to certain atoms which block the system in the mitochondria where ATP manufacturing occurs.

PHOTOSYNTHESIS

CELLULAR RESPIRATION

ECOLOGY

What is ECOLOGY??

Ecology can best be described as the study of living organisms and their environment as well as how they interact with their environment.

 

ECOLOGY

Symbiosis: A relationship in which two kinds of organisms consistently live together.•4 TYPES:– Predator-prey interactions: Both plants and animals

develop special defenses when they interact competitively with other organisms.

– Commensalism: A relationship in which one individual is closely associated with another and benefits without doing harm to the host.

 

ECOLOGY

Symbiosis: A relationship in which two kinds of organisms - Mutualism: A relationship that benefits both organisms involved.– Parasitism: A type of predation in which one organism

lives in or on a host and benefits while harming the host.

 

ECOLOGY AND THE BIOSPHEREEcosystems and BiomesPopulation: An interbreeding group of the same species.

1.Every species has a niche defined by its lifestyle factors (e.g., behavior, habitat, predation).

2.Overlap of niches results in competition until competitors are eliminated or displaced into a different niche.

ECOLOGY AND THE BIOSPHEREEcosystem:

All the biotic and abiotic factors in an area.

All the living things in an ecosystem – birds, ants, frogs, grasses, cactus, worms, lions, etc.

All the non-living things in an ecosystem – water, sunlight, temperature, shelter, oxygen or lack of oxygen, rainfall, etc.

ECOLOGY AND THE BIOSPHEREBiome: A large region with distinct plant and animal life.

ECOLOGY AND THE BIOSPHEREEnergy Flow through an Ecosystem:Energy in an ecosystem flows among organisms of different trophic levels.

ECOLOGY AND THE BIOSPHEREEnergy Flow through an Ecosystem:Food Webs:Energy passes from one animal to another as they eat plants or one another. This flow of energy from one living thing to another is called a “food web”Food Chains:A food chain is a simplified version of a food web.

ECOLOGY AND THE BIOSPHEREA “trophic level” is simply a feeding level, as often represented in a food chain, food web, or an ecological pyramid.

ECOLOGY AND THE BIOSPHERE

Primary producers comprise the bottom trophic level

Followed by primary consumers (herbivores) then secondary consumers (carnivores feeding on herbivores), and so on. The pyramid does not take into account decomposers and detritivores (organisms that feed on dead organic matter such as bacteria and fungi), which make up their own, highly important trophic pathways.

ECOLOGY AND THE BIOSPHERE

Only 10% of a trophic level’s energy flows to the next; the rest is lost to respiration, heat, and so on.

ECOLOGY AND THE BIOSPHERECycles in the EnvironmentWater cycle: Solar energy causes water to evaporate from oceans into atmosphere. Plants transpire, also sending water into atmosphere as vapor. Water vapor condenses into clouds and precipitates into rain. Rain falls back to Earth, collects on land as runoff or groundwater, and runs back into oceans.

ECOLOGY AND THE BIOSPHERECarbon cycle: Plants incorporate airborne CO2 into organic compounds (Photosynthesis!!).Primary consumers eat plants. When organisms die, their carbon is locked into fossil fuels or decomposed by microbes.Burning of fossil fuels, decomposition of organisms, and cellular respiration all release CO2 back into the air.

ECOLOGY AND THE BIOSPHERENitrogen cycle:Nitrogen-fixing bacteria convert atmospheric N2 gas into ammonium (NH4+).

Nitrifying bacteria convert ammonium into nitrites (NO2–) and nitrates (NO3–), which are taken in by plants, which are then eaten by animals.After plant or animal death, decomposers (bacteria, fungi) convert nitrogen back to ammonium (NH4+). Denitrifying bacteria process nitrogenous compounds back intoatmospheric N2 gas.