Characteristics of Living Things (Essay



Chapter 1: Statistical analysis

▪ Why are stats used?

▪ Basic stats

o What does one std dev mean? Two?

▪ standard deviation & error bars: show what?

▪ T-test?

▪ Correlation vs. causation

Chapter 2: Cells

Cell types: similarities? Differences?

o Cell theory. Why are cells small? Different sizes?

o Prokaryotes vs. eukaryotes

▪ endosymbiosis

o Cytoskeleton: define, structure?

o Chraracteristics of Living Things

• Organelles: structures, functions,.. **Which cells contain what structures??

• -nucleus?

• -Plasmids?

• -cell wall?

• -plasma membrane?

• -organelles?

• -flagella?

• -pilli?

• -ribosomes (70S vs. 80S)?

• -mitochondria?

• binary fission?

• -golgi

• lysosomes

• -chloroplasts?

• -central vacuole?

• -smooth ER?

• -rough ER

• How do organelles interact, for example ER & Golgi

• Differential Gene expression & specialization of cells?

Cell membrane: functions & structure. How is fluidity maintained? Why impt?

phospholipid bi-layer: polar heads/non-polar tails. Hydrophilic vs. hydrophobic

integral proteins (channels/ATPase) vs. peripheral proteins

cholesterol (structure): adds stability/firmness/helps maintain integrity of membrane…so not too fluid

Analysis of Membrane Proteins:

-bind substances like hormones

-channels

-pumps

Transport across cell membranes:

▪ Passive. No ATP. Energy Independent. Down the concentration gradient.

o Through membrane or open channels

o Osmosis, Diffusion, Facilitated diffusion. How? What?

▪ Active: requires ATP. Energy Dependent.

o Pumps

o Vesicular transport: endo- & exocytosis

Analysis of Cell Division: Compare & Contrast Mitosis/Meiosis

o Prokaryotes vs eukaryotes

o Cell cycle: how controlled?

o Interphase: G1, S, G2

o Mitosis vs, Meiosis.

▪ Variation? Crossing over? Independent assortment? When do they occur?

▪ Stages?

▪ Haploid vs. Diploid. 1n vs. 2n cells?

o Cytokinesis

o Cancer: what is it?

Chapter 3: Cellular Chemistry

Chemical bonding (examples?):

. -Hydrogen Bonding between Water molecules.

. -Covalent bonding between atoms w/in a water molecule. Polar vs. non-polar?

. -Ionic bonding between atoms w/ opposing charges

Properties of water:

• Polar

• Heat capacity

• Cohesive & adhesive

• Solvent

• Examples of how water is important to living things

Organic Molecules: elements in each?

Lipids: energy storage

o phospholipids vs. fats vs. fatty acids

o Differences vs. similarities

• Steroids: big molecules with carbon rings

•

Carbohydrates

- monosaccharides vs. disaccharides vs. polysaccharides

*remember condensation & hydrolysis reactions are!!

Proteins

• What is the structure of an amino acid? What makes each one unique?

• Peptide bonds between the AAs to form the proteins


• Condensation vs. hydrolysis reactions (think about linking amino acids together!)

• Levels of structure of proteins

• **types of proteins?

o Enzymes: catalysts. Reduce rate of reaction.

o Factors affecting enzyme activity (pH/Temp/Conc)

Nucleic acids/nucleotides etc… (examples: DNA/RNA/ATP). General Structure consists of:

• single PO4 + Ribose + nitrogenous base (RNA)

• single PO4 + DeoxyRibose + nitrogenous base (DNA). Histones. Nucleosomes

• three PO4 groups + Ribose + nitrogenous base (ATP)

Can you explain the importance of each category of organic molecule listed above, and give examples of each?!

**final will not include detailed questions about cell respiration or photosynthesis!!! Just the basics!

Cellular Respiration: Basic Structure of a mitochondrion

Part I. Anaerobic Respiration

Glycolysis: where does it happen? what is the result? Any ATP made?

-glucose > glyceraldehyde-3-phosphate (G3P) > pyruvate (What is produced/ where does this occur?)

-What is lactic acid (when might it build up on muscles?)

When CO2 & alcohol made?

Parts II-IV. Aerobic Respiration: Link Rxns, Krebs, ETC

-Pyruvate > Acetyl CoA (oxygen present!) ( (what is produced of this reaction? where does this occur?) 


-Krebs cycle...begins with Acetyl CoA

-What is produced in the Krebs Cycle? Where does this this cycle occur? Why is it a cycle?


-Electron Transport Chain (H+ Buildup!! ADP turns into ATP via ATP Synthase).

Photosynthesis:

- Basic Structure of a chloroplast (Thylakoid disks/ Stroma)

- What is the purpose of water in photosynthesis?

-Main products of the light reactions vs. The dark reactions


-What is the Calvin Cycle? What are the input molecules? What is the main product?

-Main products of the light reactions vs. The dark reactions. Where do they occur?

-Effects of changing: temp, light intensity, carbon dioxide

Chapters 4 & 10 Genetics

chromosome structure:

• Karyotyping

- nondisjunction

• autosomes vs. sex chromosomes

• chromosome structure

• sister chromatids vs. homologous chromosomes

• cenromeres

• gene loci = location

• genetic linkage (sex - linked genes)

• homologous vs. non-homologous chromosomes

• introns vs. exons

General Terms:

• alleles & traits & loci

• sex-linked

• homozygous vs. heterozygous genotypes

• phenotypes vs. genotypes

• dominant vs. recessive genes

• sickle cell. First genetic disease. An abnormal protein. A point mutation causes the normal protein with the AA glutamic acid to insert what AA instead?

• Co-dominance (red blood cells)

• Incomplete dominance (pink snap dragons)

Mendelian Genetics:

• Pea plants: why model organisms

• Using Punnett Squares to assess probability:

o phenotypic ratios in mono-hybrid crosses (3:1). Genotypic?

o di-hybrid crosses (9:3:3:1)

Pedigrees

• What do they show? Be able to read one. Can you tell if traits are dominant or recessive? Sex-linked?

Chapter 7: Nucleic Acids & Proteins

Central Dogma

Replication: 5’ to 3’ (leading & lagging strands)

• Meselson & Stahl expts: semi conservative replication. Draw this?

• dNTP: deoxynucleoside triphosphate. Losing the two phosphate groups provides E for forming bonds in the formation of DNA

• Figures 7.5 & 7.7. Know these

o Importance of replication bubbles…simultaneous replication

Transcription.

• Where? Why? Which strand?

• Sense vs. antisense strand. Antisense is what is transcribed. So the sense strand is like?

• Promoter & terminator sequences

• Processing of transcript:

o Removal of introns prior to translation

o Cutting into separate mRNAs

Translation: know Fig 7.12. 5’ to 3’.

• What is needed? Where does it occur?

• Ribosomes

o Subunits: large subunit with A,P, E binding sites

• Codons: AA & commands (start & stops)

• Phases

o Initiation: AUG, the start codon......read by ribosome…a tRNA w/ anticodon UAC binds to mRNA/ribosome complex

o Elongation: tRNAs bring correct AA to form the protein

▪ Translocation: movement of tRNAs across ribosomal binding sites during elongation

o Termination: one of the stop codons in the mRNA in binding site A.

▪ A release factor (a protein) catalyses release of the tRNA in binding site P…releasing the peptide.

Final study Questions: Be very sure to review all parts of each of these to fully prepare for the exam!

Essay #1

Part a. What is a cellular organelle? What features do they share in common? Are they considered a living entity? Why/Why not? Identify four different cellular organelles we’ve explored and concisely - but thoroughly state their purpose and significance within the overall cell. In other words, state specifically how each organelle helps the overall cell (animal or plant) satisfy the specific requirements all living cells must satisfy.

Part b. Please identify & briefly explain at least six unifying characteristics of all living organisms on our planet.  All of out planet’s organisms can either be categorized as prokaryotes or eukaryotes. Please explain four ways that prokaryotic & eukaryotic organisms differ structurally, and in ways they perform necessary life functions.  Please provide an example of each type of organism.

Part c. The rapid efficient passage of a multitude of materials such as water, gases (such as carbon dioxide/oxygen), ions such as sodium (Na+/H+), and dissolved solids (such as glucose), move across cell membranes is essential for metabolic processes to occur within cells. First, describe the basic nature and structure of cell membranes (include a drawing), then explain the main mechanisms involved in passive, facilitated, & active transport of materials across cell membranes.  Provide specific examples of materials moved across membranes in each type of transport. 

Part d. Osmosis involves the movement of water across cell membranes.  Explain the forces that cause the movement of water into and out of cells.  Specifically, under what circumstances will water enter a cell?  Under what circumstances will water move out of a cell? (think of hypertonic vs. hypotonic cells). What must be present for osmosis to occur?

Essay #2

Part a. What are all organic molecules are comprised of, and where are organic molecules found? Why is carbon such an important atom in all organic molecules. Most of the atoms within organic molecules are bound together with covalent bonds...what is a covalent bond?

Part b. Explain the four main categories of organic molecules we discussed in class.  What is the general structure of each organic molecule? (for example, what is the general structure of all nucleotides, compared to the general structure of all proteins, etc.).  what elements are present? Describe two (2) important functions for each one of the four types of organic molecules.

Part c. Please explain the basic structure of a DNA nucleotide. (draw a picture if possible) How do we know which end of the DNA double helix is the 3’ end and which end is 5’ end? Additionally, how does one side of the DNA molecule serve as a template for the other side? (think of semiconservative replication)

Part d. What is DNA replication? Why does it occur? In other words - why is it such an important process? Describe the major steps involved in DNA Replication & the function of the three of the enzymes we discussed in class (helicase, primase, DNA polymerase I, DNA polymerase IlI, or ligase).

Be sure to thoroughly compare and contrast continuous DNA replication & discontinuous DNA replication? (hint: what are Okasaki fragments - A.K.A. lagging strands) Additionally...What is a sister chromatid? How is a sister chromatid different from a homologous pair of chromosomes?

Essay #3

Part a. Please explain the basic structure of a DNA nucleotide. (draw a picture) How do we know which end of the DNA double helix is the 3’ end and which end is 5’ end? Additionally, how does one side of the DNA molecule serve as a template for the other side? semiconservative replication: how demonstrated by Meselson & Stahl?

Part b. What is DNA replication? Why does it occur? In other words - why is it such an important process? Describe the major steps involved in DNA Replication & the function of the enzymes we discussed in class (DNA polymerase I, III, Helicase, Primase, LIgase). Form of the free nucleiotides? Be sure to thoroughly compare and contrast continuous DNA replication & discontinuous DNA replication? (remember Okasaki fragments - lagging strands)

Essay #4

Part 1 a. What is DNA transcription? Where and why does it occur? In other words - why is it such an important process? Describe the major steps involved in transcription & explain how DNA serves as a “Code” (or template)for the production of the building blocks of an organism. Think helicase to unwind and RNA polymerase.

Part b. What is DNA translation? Where and why does it occur? In other words - why is it such an important process? Describe the major components involved in translation & explain how mRNA codons play a vital role in directing the synthesis of a very important type of organic molecule. Do not forget to thoroughly explain what tRNA’s are and their vital role! Remember: mRNA, rRNA, tRNA, nucleotides, AA, codons, anticodons

Essay #5

Part a. What is the overall purpose of cellular respiration? Photosynthesis? In very simple terms, what is the relationship between cellular respiration - which occurs in all heterotrophs and photosynthesis - which occurs in all autotrophs.

Part b. Please outline the main steps of cellular respiration.  Break this process up into two separate processes anaerobic (or glycolysis) & aerobic respiration rxns. In each process be sure to emphasize the main inputs and outputs (aka...products) What do they bring to the electron transport chain? Flow charts, or labeled diagrams are very helpful!

Finally, ATP is main output of the electron transfer chain.  What is the electron transfer chain, and where does energy come from to operate this final phase of cellular respiration?

Essay #6

Part a. In meiosis specifically, what are sister chromatids? How are they different from homologous chromosomes? What are alleles? In comparing a pair of homologous chromosomes - chromosome #1 in Humans for example - is it likely for this pair of chromosomes to contain identical alleles at each and every gene loci along the entire chromosome? Please explain your reasoning carefully!

Explain the processes of “crossing over” and “independent assortment” as they occur during meiosis.  How are these two processes fundamentally important to variation between gametes that ultimately produce genetically different offspring/siblings?

Part b. What is the difference between an organism’s genotype and it’s phenotype. What is the relationship that exists between dominant alleles & recessive alleles. Explain how an organism can be either heterozygous or homozygous for a set of alleles at a given loci. Also, what is the difference between a dominant/ recessive allele relationship & situations involving co- dominance & incomplete dominance - please provide an example of each! 

Part c. What is the purpose of a punnett square and how do they help us account for all possible alleles combinations in a cross? Additionally, Assume the following two fruit flies ( P - generation) are allowed to mate:

*A Male - homozygous recessive for sepia eyes

*A female - homozygous dominant for “wild type” red eyes

What possible genotype(s) and phenotype(s) will be expressed in the F1 generation?  Specifically, is it possible for a recessive phenotype to come forth in the F1 generation?

What possible genotypes and phenotypes will be expressed in the F2 generation?

Part d. Let’s assume we counted up and observed the phenotypes of 500 of these fruit flies in the above F2 generation, and found that their phenotypic ratios closely follow Mendelian predictions of a mono hybrid cross. 

-How many of the total of 500 fruit flies would you expect to possess red eyes?

-How many of the total of 500 fruit flies would you expect to possess sepia eyes?

* Be sure to create a punnett square to show all of the possible combinations.

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