Genes and Inheritance Flashcards
DNA and RNA function
store and process molecular information
what does DNA determine?
inherited characteristics
what does DNA direct?
protein synthesis
what does DNA control?
enzyme production
what does DNA dictate?
metabolism
what does RNA control?
intermediate steps in protein synthesis
what are nucleotides?
building blocks of nucleic acids
three parts of nucleotides
5 carbon sugar
phosphoric acid
nitrogenous base
what sugar is in DNA?
deoxyribose
what sugar is in RNA?
ribose
what are the purines?
adenine
guanine
what are the pyrimidines?
thymine (DNA)
uracil (RNA)
cytosine
what base is replaced in RNA ?
DNA has thymine and is replaced by uracil in RNA
what structure is DNA?
double stranded
what bases pair in DNA?
A-T
C-G
what types of strands does DNA have?
coding and template strands
where is DNA present?
nucleus and mitochondria
arrangement of DNA in nucleus
chromatin
chromosomes
arrangement of DNA in chromatin
loosely coiled
arrangement of DNA in chromosomes
tightly coiled
what is DNA complexed with?
proteins (histones)
how many chromosomes are there in a cell?
46 (23 pairs)
DNA arrangement in mitochondria
rings
what are genes?
segments of DNA that provide instruction for protein synthesis
what is the genome?
entire complement of cellular DNA
where does mitochondrial DNA come from?
maternally inherited
specific structure of mitochondrial DNA
double-stranded rings
how many genes are in mitochondrial DNA?
37
how many mitochondria can diseases linked to mDNA affect?
variable number
what types of diseases are mDNA diseases?
progressive
what do mDNA diseases commonly involve?
neuromuscular transmission
examples of mDNA diseases
Kearns-Sayre disease
Myoclonus epilepsy
what does RNA handle?
aspects of protein synthesis
3 forms of RNA
messenger RNA mRNA
ribosomal RNA rRNA
transfer RNA tRNA
what does mRNA do?
carries genetic information from nucleus to cytoplasm
how is information transmitted on mRNA?
as codons
when is mRNA formed?
during transcription of a gene
what does rRNA do?
makes up ribosomes
what does tRNA do?
delivers amino acids to ribosomes during protein synthesis
how does tRNA have specificity?
anticodons
what are triplets?
three base sequences of coding strand
what do triplets specify?
amino acid sequence of proteins
start and stop of transcription
characteristic of triplets
universal across nature
redundant
what does redundancy of triplets allow?
changes (mutations)
where is DNA during transcription?
trapped in nucleus
where does protein synthesis occur?
cytoplasm
what is the intermediary in transcription?
mRNA
what is synthesis of mRNA complementary to?
base sequence of a gene
what does synthesis of mRNA require?
separation of strands
what binds to promotor region?
RNA polymerase
what happens after RNA polymerase binds to promoter strand?
RNA polymerase “reads” coding strand
transcription-what do three base sequences become?
codons
what happens after mRNA is synthesized?
undergoes processing
what strand gets transcribed?
Only one strand gets transcribed (coding strand)
transcription-what are exons?
coding sequences
transcription-what are introns?
intervening non-coding sequences
what happens to introns and exons?
introns are removed and exons are spliced
what happens if introns and exons are rearranged?
different proteins are synthesized
where does processed mRNA go?
cytoplasm
what “reads” mRNA?
ribosomes
amount of tRNAs
tRNAs exist for all 20 amino acids
tRNA anticodons
specific and complementary to codons of mRNA
what does tRNA do?
deliver amino acids to ribosomes
what links amino acids together?
ribosomes
how is the amino acid sequence determined?
mRNA codons
what post-translational modification do proteins undergo?
folding
addition of lipids or carbohydrates
linkage to other proteins