-
transport work:
ATP phosphorylates transport proteins
-
mechanical work:
ATP binds noncovalently to motor proteins and then is hydrolyzed
-
exergonic reaction:
energy released, spontaneous, negative delta G
-
If DG is positive (DG>0), then free energy is _________ the reaction
consumed in
-
endergonic reaction:
energy required, nonspontaneous, positive delta G
-
A cell must ______ exergonic and endergonic reaction
couple
-
ATP hydrolysis is a(n) _______ reaction?
exergonic
-
phosphorylated intermediate:
higher energy, less stable, and thus more reactive
-
Enzymes can only allow structures that ____ it's active site
fit
-
What can penicillin do to enzymes in bacteria?
block active sites of enzymes leading to dysfunctional enzyme
-
If an enzyme is added to a chemical reaction
the activation energy will be reduced
-
Cellular respiration refers to
catabolic reactions used to generate ATP
-
Site of cellular respiration in all eukaryotic cells
Mitochondria
-
Defects in mitochondrial function can cause
degenerative diseases, cancer, aging
-
Inherited mitochondrial diseases effects
muscle weakness, degenerative disease of the CNS, metabolic dysfunction
-
The relocation of electrons from food to oxygen
released energy used to synthesize ATP
-
General Redox Reactions have Two Components
Oxidation and Reduction
-
Oxidation (X) is the
loss of electrons (increasing positive charge)
-
Reduction (Y) is the
addition of electrons (reducing positive charge)
-
In redox reaction for cellular respiration
glucose is oxidized, oxygen is reduced, and energy is released
-
What prevents glucose from instantly combining with oxygen?
Its activation energy
-
How does the transfer of electrons generate energy?
an electron loses potential energy when it shifts from a less electronegative atom to a more electronegative one
-
Transfer of electrons from fuel to transport chain is mediated by
NADH
-
Proteins, carbohydrates, and fats can all be used as fuel for
cellular respiration
-
Cellular Respiration- First Stage
- In the cytosol, glycolysis converts glucose to pyruvate
- glycolysis generates substrates for citric acid cycle and oxidative phosphorylation
-
Cellular Respiration- Intermediate Stage
pyruvate is converted to Acetyl CoA and pyruvate moves into the mitochondrial matrix
-
Cellular Respiration- Second Stage
- Citric Acid Cycle A.K.A. Krebs Cycle or Tricarboxylic Acid Cycle
- takes place in the mitochondria, converts ADP to energy-rich ATP
-
Cellular Respiration- Third Stage
- oxidative phosphorylation
- electron transport and chemiosmosis
-
What if there is no oxygen in oxidative phosphorylation?
majority of the ATP synthesis would eventually fail
-
ATP synthase allows
passive transport of H+ back to the matrix
-
A drug that specifically inhibits ATP synthase will
increase the pH difference across the inner mitochondrial membrane
-
Photosynthesis is the process by which
light is converted to chemical energy stored in sugar and other molecules
-
Autotrophs produce organic molecules from
CO2 and other inorganic molecules
-
Higher plants, protists, algae, and cyanobacteria are
Phototrophs
-
Animals, fungi, and many bacteria are
Heterotrophs
-
Heterotrophs obtain organic material from
other organisms
-
Heterotrophs ultimate depend on photoautotrophs for
food and O2
-
In photosynthesis CO2 is _____ and Water is ______
reduced, oxidized
-
What is the site of photosynthesis?
Chloroplasts
-
Where are chlorophyll molecules found?
Thylakoid membrane
-
What wavelength works best for photosynthesis?
violet-blue and red
-
Electrons in the porphyrin ring absorb
light energy (photons)
-
When chlorophyll absorbs a photon of light, the energy is conserved by
an electron going to a higher energy state
-
In photosynthesis, light reactions occur
in the thylakoid membranes
-
_____ moves down an electrochemical gradient across a membrane and drive ATP synthesis
protons
-
______ transfer chemical energy from food molecules to ATP
mitochondria
-
_______ transform light energy into the chemical energy of ATP
chloroplasts
-
Calvin cycle consists of ______,_______, and ______
fixation, reduction, and regeneration
-
Carbon Fixation
carbon dioxide is converted into organic carbon compounds, such as carbohydrates
-
What is the hereditary substance or material?
DNA
-
Which are the 4 nucleotides in DNA?
Adenine, Cytosine, Guanine, and Thymine
-
In humans A=___,T=____, G=____, and C=____
30%, 30%, 20%, 20%
-
What is the structure of DNA?
double helix
-
DNA replication begins at special sites called
origins of replication
-
At the end of each replication bubble is a
replication fork
-
What are helicases?
enzymes that untwist the double helix at the replication forks
-
What do single-strand proteins do?
- binds to and stabilizes single stranded DNA until it can be used as a template
- removes other proteins from DNA
-
What do Topoisomerase do?
corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands.
-
What enzymes catalyze the elongation of new DNA at a replication fork?
DNA polymerase
-
Most DNA polymerases require a ____ and a template strand
primer
-
Which enzyme can start an RNA chain from scratch and adds RNA nucleotides one at a time using DNA as a template?
primase
-
The leading strand moves ____ the replication fork
towards
-
The leading strand is dependent on the actions of _____ _______
DNA polymerase
-
The lagging strand moves _____ from the replication fork
away
-
The lagging strand is synthesized as a series of fragments callled _____ ______
Okazaki fragments
-
Okazaki fragments are later joined by
DNA ligase
-
____ ______ proofread newly made DNA, replacing any incorrect nucletides
DNA polymerase
-
Eukaryotic chromosomal DNA molecules have special nucleotide sequences at their ends called
tolemeres
-
Tolemeres _____ the erosion of genes near the ends of DNA molecules
postpone
-
An organism's ______ is carried in its sequence of bases
genotype
-
the ______ is a consequence of the proteins that are expressed
phenotype
-
The Central Dogma (diagram)
DNA-->RNA-->Protein
-
_____ are the linkages between genotype and phenotype
proteins
-
The process by which DNA directs protein synthesis
gene expression
-
The initial RNA transcript from any gene
primary transcript
-
Because bacteria lack nuclei, transcription and translation are
coupled
-
______ attach to mRNA molecule while transcription is still in progress
ribosomes
-
almost all transcription for eukaryotes occur in the ____
nucleus
-
______ occurs mainly at ribosomes in the cytoplasm
translation
-
How many codons in the genetic code?
64 codons
-
The genetic code is ______ but not ________
redundant, ambiguous
-
What does the genetic code is redundant but not ambiguous mean?
The genetic code is redundant (more than one codon may specify a particular amino acid) but not ambiguous (no codon specifies more than one amino acid)
-
Codons must be read in the correct ______ _______ in order for the specified polypeptide to be produced
reading frame
-
What are the three stages of transcription?
Initiation, elongation, and termination
-
RNA synthesis is catalyzed by _____ ________ which pries the DNA strands apart and hooks together the RNA nucleotides
RNA polymerase
-
RNA synthesis follows the same base-pairing rules as DNA, except ______ substitutes for _______
uracil, thymine
-
_______ ________ mediate the binding of RNA polymerase and the initiation of transcription
transcription factors
-
The completed assemble of transcription factors and RNA polymerase II bound to a promoter is called a ______ _______ ________
transcription initiation complex
-
A promoter called a ____ ___ is crucial in forming the initiation complex in eukaryotes
TATA box
-
Each end of a pre-mRNA molecule is modified in a particular way: the 5' end receives a ______ _____ ___ and the 3' end gets a ___ ___ _____
modified nucleotide cap, poly-A tail
-
RNA splicing removes ____ and joins ______, creating an mRNA molecule with a continuous coding sequence
introns, exons
-
What are spliceosomes?
large and complex molecular machines found primarily within the splicing speckles of the cell nucleus of eukaryotic cells
-
Genes produce proteins via _______ and then ______
transcription, translation
-
A cell transfers an mRNA message into a protein with the help of ____ ______
transfer RNA (tRNA)
-
Molecules of tRNA are not identical because (2 reasons)
- each carries a specific amino acid on one end
- each has an anticodon on the other end
-
The anticodon base pairs with a complementary codon on
mRNA
-
Accurate translation requires two steps; the first being
a correct match between the tRNA anticodon and an amino acid
-
Accurate translation requires two steps; the second being
a correct match between the tRNA anticodon and an mRNA codon
-
What is aminoacyl-tRNA synthetase?
an enzyme that finds correct match between the tRNA anticodon and an amino acid
-
What is a wobble and what does it do?
- a wobble is flexible pairing at the third base of a codon
- it allows some tRNAs to bind to more than one codon
-
What are the three stages of translation
initiation, elongation, and termination
-
Translation initiation steps:
- a small ribosomal subunit binds to mRNA
- a large ribosomal unit completed the initiation complex
-
Translation elongation steps:
- codon recognition
- peptide bond formation attaching the amino acid
- translocation
-
Termination of translation:
- ribosome reaches a stop codon on mRNA
- release factor promotes hydrolysis
- ribosomal units and other components dissociate
-
How is a polyribosome formed?
when a number of ribosomes translate a single mRNA simotaneously
-
What do polyribosomes enable?
it enables a cell to make copies of a polypeptide very quickly
-
The primary transcript of a gene contains
introns
-
Substrate-level phosphorylation refers to:
Generation of ATP and ADP from a phosphorylated substrate
-
A cell with a mutation in the gene that codes for actin would be most likely to show disruption in
Formation of the cleavage furrow
-
The formation of ATP by substrate-level phosphorylation requires the use of:
enzymes
-
What occurs in Meiosis I
crossing over
-
In meiosis, groups of 4 chromosomes are aligned at the equator of the spindle and their alignment determines independent assortment during:
metaphase I
-
What are the two phases of the cell cycle?
interphase and mitotic phase
-
What are the three stages of interphase?
G1, S, and G2
-
G1:
synthesis of macromolecules and cytoplasmic organelles
-
-
-
Mitotic phase:
- mitosis and cytokinesis
- equal distribution of genetic material to 2 daughter cells
-
Mitosis:
sister chromatids separate, one to each daughter cell
-
Cytokinesis:
process of division of the cytoplasm
-
What are the five subphases of mitosis?
prophase, prometaphase, metaphase, anaphase, and telophase
-
Prophase (mitosis)
- the chromosomes start to condense
- the mitotic spindle begins to form
- the nucleolus disappears
-
Prometaphase (mitosis)
- the chromosomes finish condensing
- the nuclear envelope breaks down
- the mitotic spindle grows more and some of the microtubules begin to capture chromosomes
-
Metaphase (mitosis)
all the chromosomes align at the metaphase plate
-
Anaphase (mitosis)
the chromosomes separate and each pair are pulled towards opposite ends of the cell
-
Telophase (mitosis)
- the mitotic spindle is broken down
- two nuclei form-nuclear membranes and nucleus reappear
- the chromosomes begin to decondense
-
Cytokinesis (mitosis)
- cell membrane divides
- forms a cleavage furrow before division (animal cell)
- forms a cell plate (plant cell)
-
A chromosome is:
a single DNA molecule
-
A chromosome undergoes replication in the __ phase of the cell cycle
S
-
How does a cell regulate and control the cell cycle?
checkpoints
-
Define checkpoints:
critical control points where stop and go signals regulate the cycle
-
What checkpoint did 93stop trigger according to the data?
at the end of G1
-
I f a cell does not receive a go-ahead signal at the G1 checkpoint:
the cell exists the cell cycle and goes into G0, a nondividing stage
-
______ give go-ahead signals at G1 and G2 checkpoints
Cdks (cyclin-dependant kinases)
-
What do growth factors do?
stimulates surrounding cells to divide
-
What happens when cell cycle regulations fails?
cancer
-
Cancer cells lose two aspects of a normal cell which are:
anchorage dependence and density-dependent inhibation
-
Anchorage dependence:
cells require a surface for division
-
Density-dependent inhibation
- cells form a single layer
- cells wont divide if there isn't enough space around them
-
Proto-oncogene:
- a normal cellular gene corresponding to an oncogene
- has the potential to become cancer but that requires some alteration to become an oncogene
-
Oncogene:
a gene found in viruses or as part of the normal genome that is involved in triggering cancerous characteristics
-
Tumor-suppressor genes
genes whose normal products inhibit cell division
-
What are think is best ways to cause uncontrollable cell division?
- Express an oncogene to overstimulate cell cycle
- Lose a tumor suppressor gene to remove inhibitory signaling of cell cycle
-
Why do chromosomes coil during mitosis?
to allow the chromosomes to move without becoming entangled and breaking
-
Mitosis is the way in which _______ cells divide
somatic (non-sex)
-
Meiosis is:
a special type of cell division used in sexual reproduction for the formation of gametes
-
Karyotype:
image of a person's chromosomes
-
Human cells have ___, making up ___ pairs of homologous chromosomes
46, 23
-
Which human chromosome was the first to be sequenced in its entirety?
22
-
What are the phases of meiosis I?
Prophase I, Metaphase I, Anaphase I, Telophase I, and Cytokinesis
-
Prophase I (meiosis)
- the chromosomes begin to condense and pair up
- the chromosomes begin crossing over
-
Metaphase I (meiosis)
homologue pairs—not individual chromosomes—line up at the metaphase plate for separation
-
Anaphase I (meiosis)
- the homologues are pulled apart and move apart to opposite ends of the cell
- The sister chromatids of each chromosome remain attached to one another and don't come apart
-
Telophase I and cytokinesis (meiosis)
- the chromosomes arrive at opposite poles of the cell
- two haploid cells form
-
Chiasmata
the X-shaped structure formed at the point below the brain where the two optic nerves cross over each other
-
What are the phases of meiosis II?
prophase II, metaphase II, anaphase II, telophase II, and cytokinesis (same as meiosis I)
-
Meiosis II:
- separates sister chromatids
- results in four haploid daughter cells containing unduplicated chromosomes
-
Diploid cell:
a cell that contains two sets of chromosomes
-
Haploid cell:
a cell that contains a single set of chromosomes
-
Meiosis-How is variability generated?
- Independent assortment of chromosomes
- Crossing over
- Random fertilization
-
The fruit fly has four pairs of chromosomes. The house fly has six. In which species would you expect to see more genetic variation among the progeny?
the house fly
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