L1 Readings

Question 1

what is a genome

Answer 1

the totality of a DNA sequences hereditary information embodied in the linear sequence of nucleotides in its DNA

Question 2

what are monomers of dna

Answer 2

ATGC

also known as nucleotides

Question 3

what are the three parts to dna

Answer 3

a sugar (deoxyribose)
a phosphate group
a base - ATGC

sugar and phosphate backbone with a series of bases = polymer (made up of monomers)

Question 4

is DNA synthesized as a free strand in isolation

Answer 4

no
it is made through templated polymerization - template formed by a pre existing DNA strand - AT go together and GC go together

Question 5

why are the hydrogen bonds between the base pairs in DNA weak?

Answer 5

helps it get pulled apart without breakage of their backbones - helps serve as a template for the synthesis of a fresh DNA strand complementary to itself

there is the parent DNA double strand –> pulled apart so that two more strands are made complimentary to each side (DNA replication)

Question 6

what is the central dogma

Answer 6

DNA replication - templated polymerization occurs
–>
transcription: Replicated dna strand is used as a template for the synthesis of RNA, closely related polymer
–>
translation: RNA strand is used to synthesize amino acids that make a the protein polymer

Question 7

how is RNA different from DNA

Answer 7

ribose sugar instead of deoxyribose
uracil instead of thymine (still binds with A though)

Question 8

what does the particular sequence of an amino acid chain effect

Answer 8

effects how the polypeptide folds up - giving the protein its unique 3D shape which will effect shape and function

Question 9

what makes an ordinary protein an enzyme

Answer 9

the reactive sites on the surface of the protein catalyze reactions that make or break specific covalent bonds and lead to occurrence of chemical reactions including those that make new DNA and RNA molecules (autocatalytic process and loop)

Question 10

what is mRNA

Answer 10

mRNA (messenger RNA): code for proteins

DNA is copied into mRNA by the enzyme RNA polymerase. This mRNA carries the codons, which are sequences of three nucleotide bases, each corresponding to a specific amino acid or a stop signal during protein synthesis.

in eukaryotes and prokaryotes

Question 11

what is tRNA

Answer 11

tRNA (transfer RNA): central to protein synthesis as the adaptors between mRNA and amino acids

Each tRNA molecule has a specific anticodon that pairs with a complementary codon on the mRNA. On the other end of the tRNA, it carries the corresponding amino acid that the codon specifies.

in eukaryotes and prokaryotes

Question 12

what is rRNA

Answer 12

rRNA (ribosomal RNA): form the basic structure of the ribosome and catalyze protein synthesis

rRNA helps align the mRNA and tRNA correctly within the ribosome, ensuring accurate translation of the genetic code into proteins. it forms the core structural framework of the ribosome

in eukaryotes and prokaryotes

Question 13

what is a gene

Answer 13

A gene is defined as the segment of DNA sequence corresponding either to a single protein (but sometimes to a set of closely related, alternative protein variants) or to a single catalytic, regulatory, or structural RNA molecule.

Question 14

what is regulatory DNA

Answer 14

not all genes are always expressed all the time

the cell adjusts the rate of transcription and translation according to its need

Stretches of regulatory DNA are interspersed among the segments that code for protein, and these noncoding regions bind to special protein molecules that control the rate of transcription of individual genes.

Question 15

where does a nucleotide sequence get translated to a protein sequence

Answer 15

the ribosome

Question 16

how is rRNA used to see how similar two species are to one and other

Answer 16

Ribosomes are fundamentally similar in all organisms, especially the RNA molecules that make up their core.

Although the exact sequence of these ribosomal RNAs (rRNAs) differs across organisms, they are similar enough to use them as a ruler to judge how closely two species are related: the more similar the ribosomal RNA sequences, the more recently the two species diverged from a common ancestor and the more related they must be.

additional DNA sequences can be used to further tweak how similar two species are to one and other after an estimate is made

Question 17

what are the three domains of life

Answer 17

eukaryotes
bacteria
archaea

Question 18

how do eukaryotes differ from prokaryotes

Answer 18

they have a nucleus whereas prokaryotes do not

they have membrane bound organelles that are lacking in prokaryotes

they are much bigger in size with more organelles and a larger genome (20,000 genes in humans vs 4000-6000 in bacteria)

eukaryotes –> fungi, single celled organisms, corals, animal cells

prokaryotes –> bacteria and archaea

Question 19

describe bacteria

Answer 19

• much more evolutionary diverse than eukaryotes
• very small and invisible to the eye
• loosley organized in communities
• spherical or rod shaped
• they have a cell wall (protective coat) and a plasma membrane which encloses a single cytoplasmic compartment – the cytoplasm
• contains DNA, RNA, proteins, and small molecules for life
• very organized on the inside even though its hard to see

Question 20

describe archaea

Answer 20

• poorly understood
• small and lack internal membrane bound organelles
• they differ from bacteria: diff chemistry of cell walls, membrane bound lipids, range of biochemical reactions it can carry out
• surprisingly, archaea genomes closely resemble eukaryotes even though their looks resemble bacteria
• some argue that archaea and eukaryotes should be grouped in one
• they are found in extreme and congenial surroundings
• thus diff archaea have highly diverse chemistries
• They are believed to be the predominant life-form in soil and seawater, and they play major roles in recycling nitrogen and carbon, two of the most important elements for all cells.