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Flashcards in Biology Deck (41):

Hierarchic organization

1. kingdom(largest & most inclusive)
2. phylum
3. class
4. order
5. family
6. genus
7. species (most restrictive)


scientific method

1. observation
2. hypothesis- statement or explanation of certain events
3. experiment- repeatable procedure of gathering data to support or refute the hypothesis
4. conclusion- data and its significance are explained



- 2 H atoms are covalently bonded to 1 O atom
-intermolecular bonding
-high specific heat- amount of heat to raise the temp of 1g of that molecule by 1C
-H bonding of water allows water to resist shifts in temp change
-oceans stabilize the climate
-polarity of water allows it to work as a versatile solvent


water; cohesive vs. adhesive

-H bonding results in these properties
-cohesive- ability of a molecule to stay bonded or attracted to another moelcule of the same substance
-adhesion- the ability of water to bond to or attract other molecules or substances



-long chains or polymers of sugars
-storage, strucutre and energy
-backbone of DNA and RNA


fatty acids (lipids)

-saturated fats: have no double bonds in hydrocarbon tail, solid, considered detrimental and causes cardiovascular problems
-unsaturated fats: have double bonds, liquid


phospholipids (lipids)

-contain 2 fatty acids bonded to a phosphate group
-the phosphate group is charged; polar and soluble in water
-the hydrocarbon tail of the fatty acid is non polar and non soluble in water
-helps create a barrier that protects the cell



-contribute to cell function
- polymers of 20 molecules called amino acids
-largest of the biological molecules
-enzymes- act to catalyze different reactions or processes


nucleic acids

-components of the molecules of inheritance
-DNA: code that is necessary for replication (A with T and C with G)
-RNA: used in the transfer of info from DNA to protein level. messenger in most species of the genetic code



- sum of all chemical reactions
-takes place in a series of steps: metabolic pathway
-high energy to low energy
-all reactions catalyzed by enzymes


prokaryotic cells

-lack a nucleus and do not contain membrane bound organelles


eukaryotic cells

-have a membrane-enclosed nucleus and a series of membrane-bound organelles that carry out the functions of the cell as directed by the genetic information contained in the nucleus
-more complex



-contains the DNA in organized masses called chromosomes



-contain all of the genetic information for the regeneration (repair and replication) of the cell, as well as all instructions for the function of the cell



-organelles that read the RNA produced in the nucleus and translate the genetic instructions to produce proteins
-bound ribosomes are found attached to the ER
-free ribosomes are found in the cytoplasm


endoplasmic reticulum

-membranous organelle found attached to the nuclear membrane
-rough ER- covered in ribosomes, and responsible for protein synthesis and membrane production
-smooth ER- not covered in ribosomes, functions in detoxification and metabolism of multiple molecules


golgi apparatus

- packaging, processing and shipping the organelle
- transports proteins from the ER throughout the cell



-intracellular digestion
-packed with hydrolytic enzymes, the lysosome can hydrolyze proteins, fats, sugars and nucleic acids
-normally contain an acidic environment



-membrane enclosed structures with various functions
-phagocytosis- uptake of food through the cell membrane creating vacuoles
-plant cells have central vacuoles, functions as storage, waste disposal, protection and hydrolysis



-produces cells energy
-most eukaryotic cells and is the site of cellular respiration



-produces cells energy
-found in plants and is the site of photosynthesis


cellular membrane

-contributes to protection, communication and the passage of substances into and out of the cell
-consist of bilayer of phospholipids with proteins, cholesterol, and glycoproteins
-phospholipids are amphipathic, this bilayer creates a hydrophobic region between two layers of lipids, making it selectively permeable


cellular respiration equation

C6H12O6 + 6O2 -> 6CO2 + 6H2O


steps of cellular respiration

-ATP and NADH are required
1. glycolysis- conversion of glucose to pyruvate
-takes place in the cytosol and produces 2 molecules of ATP, 2 molecules of pyruvate and 2 molecules of NADH
2. pyruvate is transported into a mitochondrion and used in CAC
- occurs in the matrix of the mitochondria
-for a single consumed glucose molecule, 2 ATP molecules, 6 carbon dioxide and 6 NADH are produced
3. begins with the oxidation of the NADH molecule to produce oxygen and finally produce water, in steps of ETC
- for every glucose molecule, 28 to 32 ATP molecules can be produced
-overall ATP production 32-36 ATP molecules for every glucose molecule consumed



-reverse of cellular respiration
-equation: 6CO2 + 6H2O + Light energy -> C6H12O6 + 6O2
-energy needed to produce glucose
-light reactions and the calvin cycle


light reactions: photosynthesis

-convert solar energy to chemical energy
-cell accomplishes the production of ATP by absorbing light and using that energy to split a water molecule and transfer the electron, creating NADPH and producing ATP
-these molecules are then used in the Calvin Cycle to produce sugar


Binary fission: asexual reproduction

-involves bacterial cells
-the chromosome binds to the plasma membrane, where it replicates
- then as the cell grows, it pinches in two, producing two identical cells


Mitosis: asexual reproduction

-occurs in 5 stages before pinching in two in a process called cytokinesis
-5 stages: prophase, prometaphase, metaphase, anaphase and telophase
1. prophase- the chromosomes are separate, and each duplicated chromosome has two sister chromatids
2. prometaphase- the nuclear envelope begins to disappear, and the chromosome begin to attach to the spindle that is forming along the axis of the cell
3. metaphase- all chromosomes aligning along the metaphase plate or center of the cell
4. anaphase- begins when cells start to separate, the chromatids are considered separate chromosomes
5. telophase- chromosome gather on either side of the now separating cell
-cytokinesis is separate from phases of mitosis
- the cell pinches in two, forming two separate identical cells


sexual reproduction

- 2 cells contribute genetic material, resulting in significantly greater variation
-2 cells find and fertilize each other randomly, making it virtually impossible for cells to be alike


sexual reproduction: meiosis

-2 stages Meiosis I and II, resulting in 4 daughter cells
-each daughter cell contains half as many chromosomes as the parent
-interphase- when the chromosomes are duplicated and the cell prepares for division


mitosis vs. meiosis

- both have the same 4 stages
- biggest difference is in prophase I
- in meiosis during prophase I, nonsister chromatids of homologous chromosomes cross at numerous locations
-small sections of DNA are transferred between these chromosomes resulting in increased genetic variation
-the remaining phases are the same as those in mitosis with the exception of chromosome pairs separate, not the chromosomes themselves



- using garden pea plants, Gregor Mendel discovered the basic principles of genetics
-he was able to determine that the observable traits in peas were passed from one generation to the next


genetics: alleles

- in Mendels study, it was found that for every trait expressed in a sexually reproducing organism, there are at least two alternative versions of a gene (allele)
-versions can be dominant or recessive
-if both alleles are the same then they are homozygous
-if both alleles are different they are heterozygous


Punnett square

- it is possible to predict the genotype (combination of the alleles) and the phenotype (what traits will be expressed)



-the genetic material of a cell and is the vehicle of inheritance


structure of DNA

-1953, Watson and Crick described DNA as a double helical structure that has 4 nitrogenous bases; A, T, G and C
-each base forms a H bond with another base on the complementary strand


replication of DNA

- the strands are separated
-with the help of several enzymes, new complementary strands to each of the two original strands are created
-this produces 2 new double-stranded segments of DNA identical to the original
-when DNA makes a copy of itself, it "unzips" to expose nucleotide bases
- enzyme DNA polymerase unzips it
-after all bases have new pairs, 2 identical DNA molecules will be ready for distribution to the two daughter cells


DNA: transcription

- each gene along a strand of DNA is a template for protein synthesis
-begins with transcription
-in this process, an RNA strand, complementary to the original strand of DNA is produced
-the piece of genetic material produced is mRNA



- functions as the messenger from the original double helix in the nucleus to the ribosomes in the cytosol or on the rough ER
-here is where translation happens


DNA: translation

-ribosomes act as the site of translation
-the mRNA slides through the ribosome
-every group of 3 bases along the stretch of RNA is a codon, and each codes for a specific amino acid
-anitcodon is located on a unit called tRNA



- anticodon is located on here
- tRNA carries a specific amino acid
-it binds to the ribosome when its codon is sliding through the ribosome
-a protein is a polymer of amino acids, and multiple tRNA molecules bind in order and released by the ribosome
-each amino acid is bonded together and released by the preceding tRNA molecule, creating a elongated chain of amino acids
-chain ends at a stop codon
-at this point the chain is released into the cytoplasm, and the protein folds onto itself and forms its complete conformation
-as amino acids are brought into the proper sequence, they are joined by peptide bonds and form a long strands of polypeptides