Aveneu Park, Starling, Australia

Not (Clancy). The rRNA does not carry the

Not
all transcribed genes translate into protein. 
The DNA that makes up the human genome contains thousands of genes and
each gene carries a unique protein that performs a function in the cell.  Cells use
the transcription and translation process to read each gene and produce the
string of amino acids that create protein.  In order for genes to make a product, they
must first be transcribed into RNA.  In
all eukaryotic cells the DNA stays in the nucleus, then the genes are copied into
RNA which they are transported into the
cytoplasm to make protein. (Nobleprize.org). 
Every protein in the body is made from a gene that was translated from
the genetic code, but not all genes translated into protein, such the ribosomal
RNA (rRNA).  This is because rRNA is associated with ribosomal protein to make
ribosomes.  In the translation process,
messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce
a specific amino acid chain. The amino acids later fold into an active protein and perform
its functions in the cell (Clancy).  The
rRNA does not carry the code in making proteins.  Rather, it forms the two ribosomal subunits,
one large and one small, that make up a ribosome. The large subunit serves as a
ribozyme that acts as an enzyme that catalyzes peptide bond formation between
two amino acids (Pearson Education).

2. How do species evolve
from a common ancestor?

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Everybody
believed that human beings had twenty-four pair of chromosomes.  In 1955 Joe-Hin Tjio and Albert Levan
discovered that humans have only twenty-three pair of chromosomes.  Chimpanzees, gorillas, and orangutans
have twenty-four pairs of chromosomes.  The
reason is not that we are missing a pair of the ape’s
chromosome, but that two ape chromosomes have combined together in the human body (Ridley).  The similarity in DNA sequences provides
evidence that humans and chimpanzees are descended from a common ancestor with
the apes.  Since the time of Darwin, scientists
have found that human’s genomes are 96 percent similar and a 4 percent difference
between us and chimpanzees (Lovgren).  The
difference between humans and chimpanzees lies in the measurement of substitutions
in the base building blocks of those genes that chimpanzees and humans share.  When both genomes
were compared, this indicated that segments
of DNA have also been eliminating, duplicate or inserted from one
part of the genome into another (Genetic Evidence).       

3. What are start codon, stop codon and reading
frame? 

“Genes
are one of the biological units of heredity, self-reproducing, and located at a
definite position on a particular chromosome.  Genes make up segments of the complex
deoxyribonucleic acid (DNA) molecule that controls cellular reproduction and
function” (Polyak).  There are two signals
in the genetic code called the START and STOP codons which signal the end of
protein synthesis in all organisms.  There are a total of 64 codons in the
genetic code and each codon encodes for one of the 20 amino acids used in the
synthesis of protein (The Genetic Code). 
A codon is a set of three bases in a DNA or RNA chain that define a
single amino acid sequence for the protein that is encoding.  Some amino acids can be coded by more than
one triplet codon (Berg).  Start codon marks the site at which
translation into protein sequence begins and is the first codon in the
transcribed mRNA that undergoes translation.  AUG is the most common start codon and it
codes for the amino acid methionine (Met) in eukaryotes.  During protein synthesis, the tRNA recognizes
the start codon AUG with the help of at least three proteins called initiation
factors and starts translation of mRNA (Translation or Protein Synthesis).  There are 3 stop codons in the genetic code –
UAG, UAA, and UGA.  These codons signal
the end of the polypeptide chain during translation. These codons are also
known as termination codons, as they do not code for an amino acid.  During protein synthesis, stop codons
cause the release of the new polypeptide chain from the ribosome. This occurs
because there are no tRNAs with anticodons complementary to the stop codons (Translation
or Protein Synthesis).  The start codon
creates a reading frame where codons are read in order until a stop codon
terminates protein synthesis.    

4. How was the
alkaptonuria (black urine disease) mutation identified? 

Most
of what we know about ourselves actually comes from the studies of
microorganisms.  By
studying diseases, a scientist has gained an understanding of the basic structure
of life which include how cells replicate their DNA and how they decode genetic
instructions to make proteins.  In 1902, Archibald
Garrod came across a number of patients with a race but not a dangerous disease, known as alkaptonuria.  Alkaptonuria is a rare inherited disorder distinguish
by dark brown or black urine when exposed to air (Ridley).  He noticed that most of these cases were first-cousin
marriages, but he realizes that this
illness was not simply passed on from parent to child
because most of the patients had normal children.  Therefore he knew this was a condition that
could carried by one generation, but would only shown
if it’s inherited from both parents. 
According to Garrod, the reason the disease appears only in patients
with a double inheritance was that the
gene that was supposed to be breaking down the enzyme called homogentisate was
not functioning properly, therefore was producing a defective enzyme (Ridley).  These enzymes are supposed to help break down
amino acids that are important building block of proteins.  When the enzyme does not break down, it accumulates in the body causing cartilage
and skin to darken.  Over time, the
accumulation of this enzyme is eliminated
in urine, making the urine turn dark when exposed to air (Genetics Home
Reference).             

5. How did human
populations adapt to alcohol consumption and how did they adapt to milk
consumption in adult life?

Human
ancestors began evolving their ability to
consume alcohol about 10 million years
ago.  The ability to break down alcohol
helped human ancestors make the most out of rotting, fermented fruit that fell
onto the floor (Choi).  Sugars in fruit are
naturally turned into ethanol by yeasts during fermentation and primate
ancestors survived mostly on fruits.  The
scent of alcohol from ripe fruit travels long distances and may have helped
primates to find their next meal.  Being
able to detect the scent of ethanol from ripe fruits would have been
evolutionary adaptive allowing the primate to find food easier.  Human ability to break down a large amounts of alcohol depends on a set of
genes that code for a group of digestive
enzymes called alcohol dehydrogenases enzymes (Ridley).  Alcohol dehydrogenase is our primary defense
against alcohol and performs the important step in breaking down ethanol after
it is consumed.  

Ancestors
without the alcohol dehydrogenase, allow the ethanol to quickly build up in the
blood making them more easily to get sick. 
The capacity to consume ethanol may have helped
human ancestors consume rotting, fermenting fruit that fell on the ground when
food was limited (Choi).  The use of dairy
show us how natural pressures have helped
transform human DNA.  At the beginning of
agriculture, humans were able to domesticate animals such as sheep, goats, and cows and they became the main source of milk. 
Milk was only consumed by babies because they are able to absorb milk
without getting sick and this is thanks to an enzyme called lactase.  Several thousand years ago, this enzyme was turned
off once a person grew into adulthood, therefore, most adults are lactose
intolerant.  Different human populations
not only eat different foods, but their digestive systems usually use them in
different ways.  This
indicates that humans have adapted to the foods they need for health and growth
(Ridley). Lactose intolerant is usually due to an inability to produce enough amounts
of the enzyme lactase which “breaks down lactose into glucose and galactose in
the small intestine to aid its absorption into the bloodstream”.  Opportunities have led to the evolution of related genetic
differences among the populations of the world. 
The different development changes between different societies has let
distinct population to consume dairy as
adults (O’Neil).      

x

Hi!
I'm Mack!

Would you like to get a custom essay? How about receiving a customized one?

Check it out