Lecture 1 Flashcards
a cell is a fundamental unit of –
living matter
all living things are made up of –
cells
what is the fundamental feature of a cell?
ability to reproduce successfully
All cells contain the same three macromolecules – to carry out their fundamental properties of life
DNA, RNA, and protein
macromolecules are
made up of monomers connected by covalent bonds (polymers)
genetic info flows from
DNA –> RNA –> protein
every time a cell divides, – occurs so that all cells should have the same DNA
DNA replication
gene expression =
transcription + translation
all cells store – in the same linear chemical code - the DNA
hereditary info
Why is DNA more suitable than RNA to carry genetic info?
RNA has a hydroxyl group in the 2’ position of its ribose sugar which is very reactive
DNA does not have a hydroxyl group in the 2’ position of its deoxyribose and is therefore more stable
DNA also forms a stronger double helix (while RNA is single-stranded) and the hereditary info can be replicated by templated polymerization
all cells replicated DNA by
templated polymerization
– provides a way to make two molecules of genetic info exactly the same
double-stranded
2 strands of a DNA double helix are pulled apart and each serves as a template fro the synthesis of a new -
complementary strand
DNA is not synthesized as a free strand in isolation but on a – formed by a preexisting DNA strand
template
during growth, eukaryotic cells continually progress through – stages of the cell cycle, generating new daughter cells
four
resting cells
G0
RNA and protein synthesis
G1/G2
DNA replication
S
Cell division
M
T/F: cell division produces two daughter cells with identical hereditary material (DNA)
true
All cells transcribe – of their hereditary information into the same intermediate form - RNA
portions
template to make protein
RNA
DNA is protected in the –
nucleus
translation occurs in the –
cytoplasm
RNA is the suitable template for proteins because
RNA transcripts are mass produced and disposable
many different sets of RNA molecules can be made by – different parts of a cell’s DNA sequence
transcribing
different types of cells can use the same info –
differently
A nucleotide pairing between different region s of the – RNA polymer chain causes the molecule to adopt a distinctive shape
same
all cells use – as catalysts
proteins
like nucleic acid, proteins are long unbranched –
polymers
A feedback loop that connects proteins and polynucleotides form the basis or – of living organisms
autocatalytic, self-reproducing behavior
info in the sequence of mRNA is read out in 3 nucleotides at a time =
codon
codon specifies a single –
amino acid
T/F: There are 64 possible codon all of which occur in nature
true
there are only – naturally occurring AA
20
T/F: several codons correspond to the same AA
true
tRNA is attached to a – at one end and an anticodon at the other end that corresponds to a particular codon in mRNA
amnio acid
ribosomes are a large multi molecular machine composed of
protein and rRNA
segment of the DNA sequence corresponding to a single protein or a single catalytic, regulatory, or structural RNA molecule
gene
in all cells, the – are regulated
expression of individual genes
stretches of – are intersperse among coding DNA
regulatory DNA
totality of genetic info in the complete DNA sequence
genome
Why is glucose not the main source of energy?
1 glucose = a lot of ATP
burn glucose –> waste a lot of energy
– is the chemical currency of cells
ATP
all cells are enclosed in a
plasma membrane
membrane is formed by – phospholipid molecules
amphiphilic
in an aqueous environment, phospholipids spontaneously form a lipid bilayer because it’s
thermodynamically favorable
advantages of plasma membrane
protect cell, control what goes in and out (selectively permeable)
phospholipids spontaneously aggregate in water to create a bilayer that forms –
closed vesicles
hox genes were – during evolution
conserved
Drosophila eyeless and Human Pax6 are examples of
conserved genes
