Genetics Part 1 Flashcards
function of NUCLEIC ACIDS + where are they found?
- Essential to FORMS OF LIFE
- found in DNA + RNA
What are MACROMOLECULES?
- composed of specific MONOMERS—make up a NUCLEOTIDE
What THREE COMPONENTS make up a NUCLEOTIDE?
- 5-CARBON SUGAR
(Either ribose or deoxyribose) - PHOSPHATE GROUP
- NITROGENOUS BASE
- adenine
- cytosine
- thymine
- guanine
Describe DNA POLYMERIZATION
how are NUCLEOTIDES BONDED?
What are the RESULTS?
DNA POLYMERIZATION:
- the creation of a SINGLE STRAND OF DNA with TWO DIFFERENT ENDS
(5’ & 3’ strands)
NUCLEOTIDES:
- bonded through DEHYDRATION REACTIONS
RESULTS:
- SUGAR-PHOSPHATE BACKBONE
- NITROGENOUS BASES —stick out from backbone
- PHOSPHODIESTER BONDS (links the DEOXYRIBONUCLEOTIDES) :)
What’s DNA’s STRUCTURE within the CELL?
Consists of TWO NUCLEOTIDE STRANDS that are specifically COILED around each other— DOUBLE HELIX
Describe the FOUR NITROGENOUS BASES OF DNA
PURINES:
- ADENINE
- GUANINE
PYRIMIDINES:
- CYTOSINE
- THYMINE
PAIRINGS:
A + T
C + G
**held together by HYDROGEN BONDS
Describe the BASE PAIRING IN DNA–C+A
BASE PAIRING:
- important in terms that DNA PAIRING is defined as COMPLEMENTARY & ANTIPARALLEL
COMPLEMENTARITY:
- important for the PRECISE DUPLICATION OF DNA during CELL DIVISION
- the sequence of ONE STRAND can help determine the OTHER SEQUENCE
STRAND
ANTIPARALLEL:
- the HEAD of one strand is laid against the TAIL of the other strand
- important in terms of REPLICATION—strands can REPLICATE DIFFERENTLY
Describe the CHARACTERISTICS OF RNA
RNA:
- SINGLE STRANDED
NUCLEOTIDES:
- different nucleotide: URACIL REPLACES THYMINE
FUNCTION:
- CONVERTS GENETIC INFORMATION into PROTEINS
* mRNA
* tRNA
*rRNA
what is GENETICS?
GENETICS:
- the study of HEREDITY
- the study of GENES—how they carry information that makes US
- how that information is REPLICATED to be passed down to other GENERATIONS
- how they make PROTEINS necessary for LIFE
What is a GENOME?
The genetic information in a cell (seen either within a CHROMOSOME or PLASMID)
what are CHROMOSOMES?
DNA CONTAINING STRUCTURES that contain all of our GENETIC INFORMATION in the form of GENES
what are GENES?
segments of DNA that code for a FUNCTIONAL PROTEIN or RNA
describe the EUKARYOTIC CHROMOSOME STRUCTURE
STRUCTURE:
- shape is LINEAR
- has TWO COPIES PRESENT or SINGLE COPY
- these specific linear strands of DNA begin to WRAP AROUND HISTONES + PROTEINS = CHROMOSOMES
- also has NON-CODING REGIONS on the CHROMOSOME
describe the BACTERIA CHROMOSOME STRUCTURE
STRUCTURE:
- seen within the CYTOPLASM
- the CHROMOSOMES are CIRCULAR
(only SINGLE COPY)
- DNA is SUPERCOILED
definition of GENOTYPE
the GENETIC MAKEUP of an ORGANISM
- POTENTIAL properties
definition of PHENOTYPE
an organism’s OBSERVABLE TRAITS and CHARACTERISTICS
- the ACTUAL EXPRESSED properties
definition of GENOMICS
the SEQUENCING and MOLECULAR characterization of GENOMES
describe the DNA’s GENETIC CODE
GENETIC CODE:
- based on the actual LINEAR SEQUENCE of the bases (ATCG)
(gives the information that tells the cell WHAT PROTEINS to MAKE)
- creation of the SET OF RULES by which DNA is translated into PROTEINS
(DNA to RNA to PROTEINS)
**all of this processes undergo the pathway of the CENTRAL DOGMA
describe the CENTRAL DOGMA and its PATHWAY
CENTRAL DOGMA:
- describes the FLOW of INFORMATION from DNA > RNA > PROTEINS
*again, DNA has all of the INFORMATION needed to make PROTEINS
PATHWAY—
DNA (TRANSCRIBED) > mRNA
mRNA:
- the MESSENGER of INFORMATION
mRNA (TRANSLATED) > PROTEINS
definition of PROTEINS
PROTEINS:
the FUNCTIONAL UNITS of LIFE (in terms of STRUCTURE, CARRIERS, and ENZYMES)
what is REPLICATION
REPLICATION:
- when ONE CELL separates into TWO
DNA must be REPLICATED FAITHFULLY for BOTH DAUGHTER CELLS
**DNA - DOUBLE STRANDED
PARENT dsDNA:
- the ORIGINAL “old” strand becomes the TEMPLATE
- production of TWO NEW COMPLEMENTARY STRANDS
what is SEMI-CONSERVATIVE REPLICATION?
PARENT dsDNA:
- again we have the original “OLD” strand–the TEMPLATE
- production of two NEW ALTERNATING COMPLEMENTARY STRANDS
- each daughter INHERITS ONE NEW STRAND + ONE OLD STRAND
describe and list the REPLICATION STEPS
START:
- the ORIGIN of REPLICATION
- the start of the new synthesis of DNA REPLICATION–remember it always starts from 5’ to 3’
*PROKARYOTES–has ONE ORIGIN
*EUKARYOTES–has MULTIPLE ORIGINS
STEPS:
- UNWIND
- UNZIP
- PRIME
- REPLICATE
what are the COMPLEMENTARY ENZYMES that CORRELATE to the REPLICATION STEPS?
UNWIND:
- DNA GYRASE
helps with RELAXING the SUPERCOILING of the DNA
UNZIP:
- DNA HELICASE
unwinds the DNA HELIX–and begins to OPEN the dsDNA (the origin of replication, along the replication fork)
PRIME:
- RNA PRIMASE
specific INDICATOR with a PRIMER RNA with 5’ to 3’ –begins to START a SMALL SECTION of RNA (before the start of replication)
REPLICATE:
- DNA POLYMERASE
enzyme that begins to SYNTHESIZE the NEW STRANDS **we can only add NUCLEOTIDES to 3’ END–can only ELONGATE 5’ to 3’
what is the DIRECTION of REPLICATION?
bidirectional
How ACCURATE is DNA REPLICATION?
- amazingly accurate; ERROR RATE is 1 in 10 BILLION BASES
- have specific PROOF READING by DNA POLYMERASE; incorporates NUCLEOTIDES with every NTP + checks base pairings and FIXES MISTAKES
What are the DIFFERENCES BETWEEN PROKARYOTIC AND EUKARYOTIC DNA REPLICATION?
PROKARYOTES—
RNA PRIMER LENGTH: 50 nucleotides
DNA POLYMERASE: I, II, III
NUMBER OF ORIGINS: SINGLE
NUCLEOTIDE LENGTH (OKAZAKI): 1000-2000 NUCLEOTIDES
RATE OF REPLICATION: 500 nucleotides/sec
EUKARYOTES—
RNA PRIMER LENGTH: 9 nucleotides
DNA POLYMERASE: alpha, beta, gamma..?
NUMBER OF ORIGINS: MULTIPLE
NUCLEOTIDE LENGTH (OKAZAKI): 200 NUCLEOTIDES
RATE OF REPLICATION: 50 nucleotides/sec
How DO CIRCULAR CHROMOSOMES DIVIDE? What’s an IMPORTANT ENZYME for its DIVISION?
- has own set of DAUGHTER AND PARENT STRAND
- own junctions of REPLICATION FORKS
- REPLICATION proceeds in both directions
ENZYME TOPOISOMERASE:
separates the two loops
describe the LEADING and LAGGING STRANDS of DNA
- LEADING STRAND:
- has only ONE PROPER PRIMER RNA
- steady process/ no stopping segments
- LAGGING STRAND:
- cannot have proper primer RNA
- utilizes in step to step components/segments instead
- due to the synthesis of primer RNA—has to go from 5’ to 3’
**these primer RNA cannot stay within the strands
- has editing capabilities to change RNA into DNA
function of POLYMERASE I and DNA LIGASE
- POLYMERASE I:
- removal of RNA by 5’ to 3’ exonuclease
- fills the gap with DNA
- DNA LIGASE:
- joins together the Okazaki fragments
