BISC207- Exam 3

Enzymes are mostly protein _____

catalysts

-bring reactants together in precise orientations
-make reactions more likely
- are specific for a single type of reactions

catalysts

Substrates bind to the enzyme's _____ _____

active site

Substrates bind via _____ _____ or other interactions with amino acid residues in the active site

hydrogen bonding

Enzymes lower the _____ _____

activation energy

_____ affects the folding and movement of the enzyme and binding its substrates

temperature

_____ affects the enzyme's shape and reactivity

pH

_____ is key to enzyme action

specificity

location where reaction takes place

active site

reactants that bind to active site

substrate

_____ inhibitors bind to the active site of the enzyme & prevent substrate from binding

competitive

_____ inhibitors bind to a site different from the active site & slow reaction normally catalyzed by the enzyme by altering the enzyme's shape

noncompetitive

_____ increase activity of enzymes

activators

process that occurs in the cytoplasm

glycolysis

three processes that occurs in the mitochondria

-pyruvate oxidation/acetyl CoA synthesis
-citric acid cycle
-oxidative phosphorylation

_____ is oxidized through a long series of carefully controlled redox reactions

glucose

released free energy from oxidation of glucose is used to _____ _____

synthesize ATP

process in which glucose is split into two molecules of pyruvate

glycolysis

products of glycolysis

2 pyruvate, 2 ATP, 2 NADH

ATP is made by _____ _____ phosphorylation

substrate level

No _____ is consumed in the process of glycolysis

oxygen

processes that occur in the inner mitochondrial membrane

-electron transfer
-ATP synthesis by ATP synthase

process that occurs in the mitochondrial matrix

reactions removing electrons from fuel molecules (pyruvate oxidation, citric acid cycle)

in the presence of _____, pyruvate can be further broken down to release more energy

oxygen

pyruvate from glycolysis is transported into the mitochondrial matrix where it is converted to _____

acetyl-CoA

in the citric acid cycle, each acetyl-CoA is completely oxidized into two _____

CO2

products of citric acid cycle

6 NADH, 2 FADH2, 2 ATP, 4 CO2 (from two acetyl-CoA)

electrons picked up through redox reactions by carriers are released by the reduced forms of the carrier molecules _____ and _____

NADH, FADH2

the transfer of electrons is coupled with the transport of _____ across the membrane

protons

_____ and _____ are ultimately transferred to oxygen to form water

electron, protons

energy used to establish H+ gradient across the membrane drives synthesis of _____ from _____ and _____

ATP, ADP, and Pi

final acceptor in ETC

oxygen

without oxygen in the ETC, _____ stop flowing, therefore not enough _____ is made

electrons, ATP

places where carbon dioxide enters and oxygen exits the leaf

stomata

reactions in which energy from sunlight is converted into chemical energy to replenish ATP and NADPH

light-dependent reactions

reaction in which excess energy is stored by building high-energy sugar molecules to be used when sunlight is not available

light-independent reactions (Calvin cycle)

light-dependent reactions produce _____ from H2O

O2

high-energy electrons from splitting water are transferred to the electron carrier _____, forming _____

NADP+, NADPH

light-dependent reactions occur in the _____

thylakoids

O2 produced in thylakoid lumen by oxidation of _____ by PSII

oxidation

_____ produced in the stroma from high-energy electrons

NADPH

_____ produced in stroma by H+ electrochemical gradient

ATP

the Calvin cycle reactions produce sugar from _____

CO2

_____ and ______ are used to reduce CO2

electrons, ATP

during Calvin cycle, ______ provides electrons and hydrogen

NADPH

during Calvin cycle, ______ provides additional energy

ATP

Calvin cycle- for every 6 CO2 incorporated, 18 _____ and 12 ______ are used

ATP, NADPH

used in the Calvin cycle to catalyze the first major step of carbon fixation

rubisco

nuclear division that leads to halving of chromosome number

meiosis

produces clones that are genetically identical to one another and to the parent

asexual reproduction

produces offspring with unique chromosome complements

sexual reproduction

when replication is complete, each chromosome has two identical ______ ______

sister chromatids

cell division where the two homologs of each chromosome pair separate into two daughter cells; each daughter cell has one set of chromosomes (haploid)

meiosis I

cell division where the sister chromatids of each chromosome separate into two daughter cells; results in four haploid cells

meiosis II

the daughter cells become eggs or sperm by the process of _____

gametogenesis

phase where exchange/crossing over between homologous non-sister chromatids occurs

late prophase I

X-shaped regions where crossing over occurred

chiasmata

phase where chromosomes separate and start moving toward opposite poles, but the sister chromatids remain attached at their centromeres

anaphase I

meiosis I results in daughter cells with only one chromosome of each _____ _____

homologous pair

no _____ ____ occurs between meiosis I and meiosis II

chromosome replication

_____ gives rise to four haploid cells with un-replicated chromosomes

meiosis II

crossing over contributes to genetic variability between _____ _____

homologous chromosomes

Error in meiosis in which homologous chromosomes fail to separate

nondisjunction

homologs pair in _____ but not in ____

meiosis, mitosis

_____ permits flexibility and survival of a population in the face of changing environmental circumstances

variation

SNPs

single nucleotide polymorphisms

______ are scattered throughout the genome and are found in both coding and noncoding regions

SNPs

______ can cause silent, harmless, harmful, or latent effects; stable from generation to generation; useful gene markers

SNPs

mating parents with two different phenotypes for a single trait

monohybrid cross

hypothesis that hereditary determinants do not blend or change through use; they act as discrete, unchanging particles

particulate inheritance

hereditary determinants for a trait

genes

non-sex chromosomes

autosomes

chromosomes of the same type

homologous chromosomes (homologs)

pair of homologs

homologous pair

homologous pairs contain the same ____ genes in the same position along the chromosome, but the two homologs are not identical

genes

base-pair sequence that specifies where transcription begins

promoter

a base-pair sequence that includes coding information for the polypeptide chain specified by the gene

coding sequence

sequence that specifies the end of the mRNA transcript

terminator

the process of using a DNA template to make a complementary RNA

transcription

the process of using the information in mRNA to synthesize proteins; interprets nucleotide "language" to amino acids

translation

summarizes the flow information in cell; DNA to RNA to proteins

central dogma

_____: RNAP recognize and bind to promoter

prokaryote

_____: transcription factors bind first, then RNAP II

eukaryote

transcription factor (TF) + RNAP

transcription initiation complex

transcription is the synthesis of an RNA copy of a segment of DNA (gene) by the enzyme _____ ______

RNA polymerase

RNA polymerases perform template-directed synthesis in the ___' to ___' direction

5, 3

transcription of genes occur in the _____

nucleus

translation occurs in the

cytoplasm

-Modified guanosine attached to 5' end
-Needed for mRNA to exit nucleus and bind ribosome

capping

Process that removes introns from pre-mRNAs and joins exons together

mRNA splicing

non-coding regions of DNA; may take the form of short (or long) repeated sequences within the gene; initially transcribed but then spliced out

introns

portion of a gene that is actually transcribed and spliced together to make the final mRNA product

exons

catalyzed by small nuclear ribonucleoproteins or snRNPs; from complex called a spliceosome

splicing

a modified guanine nucleotide that enables ribosomes to bind and protects from degradation

5' cap

100-250 adenine nucleotides needed for translation and protects from degradation

3' poly(A) tail

contains information transcribed from DNA

mRNA

-contains two functional cites
1. anticodon- recognizes a codon
2. has appropriate amino acid attached to it

tRNA

located in the cytoplasm of the cell; directs the translation of mRNA into proteins

rRNA

found to carry information from DNA to the site of protein synthesis

mRNA

-synthesizes RNA
-uses a DNA strand as a template
-copies the code by matching complementary nucleotides

RNA polymerase

synthesizes DNA from an RNA template

reverse transcriptase

the way a cell's mRNA-translating machinery groups the mRNA nucleotides into codons

reading frame

a ______ bond forms with each amino acid based off the codon sequence

peptide

acceptor site for an aminoacyl tRNA

A site

peptidyl site where a peptide bond forms

P site

site where tRNAs without amino acids exit the ribosome

E site

any permanent change in an organism's DNA

mutation

result from one or a small number of base changes

point mutation

mutation that changes an amino acid in the protein

missense mutation

mutation that does not change the amino acid sequence due to redundancy in the code

silent mutation

mutation that changes a codon that specifies an amino acid into a stop codon

nonsense mutation

mutations that shift the reading frame, altering the mean of all subsequent codons

frameshift mutations