12. • Within cells, structures called chromosomes contain genetic
material in the form of DNA (deoxyribonucleic acid).
• Before a cell divides, the DNA is first replicated, or copied,
and each of the two cellular offspring inherits a complete set of
chromosomes, identical to that of the parent cell. Each
chromosome contains one very long DNA molecule with
hundreds or thousands of genes, each a section of the DNA of
the chromosome.
• The molecular structure of DNA accounts for its ability to
store information. A DNA molecule is made up of two long
chains, called strands, arranged in a double helix. Each chain is
made up of four kinds of chemical building blocks called
nucleotides, abbreviated A, T, C, and G.
12
15. • The entire “library” of genetic instructions that an
organism inherits is called its genome.
• A typical human cell has two similar sets of
chromosomes, and each set has approximately 3 billion
nucleotide pairs of DNA.
• Rather than investigating a single gene at a time,
researchers study whole sets of genes (or other DNA)
in one or more species—an approach called genomics.
• Likewise, the term proteomics refers to the study of
sets of proteins and their properties. (The entire set of
proteins expressed by a given cell, tissue, or organism
is called a proteome).
15
16. A gene is a stretch of DNA or RNA that determines a certain trait.
Genes mutate and can take two or more alternative forms;
an allele is one of these forms of a gene.
Genotype is the actual set of alleles carried by the organism. This
includes alleles that are not "expressed." i.e., alleles that do not
end up influencing the specific trait that they code for.
The phenotype is the expression of the genes. i.e., the specific
traits that are observed as a result of the genetic makeup of
the organism.
A genome is an organism's complete set of DNA, including
all of its genes. Each genome contains all of the information
needed to build and maintain that organism. 16
28. DNA is anti-parallel
Anti-parallel means
that the 1st strand runs
in a 5’→ 3’ direction
and the 2nd 3’→ 5’
direction
THEY RUN IN
OPPOSITE or ANTI-
PARALLEL
DIRECTIONS
28
http://dnastructureandreplication.weebly.com
/enzymesanti-parallel.html
30. Replication
30
The replication of chromosomal DNA begins at particular sites called origins of
replication, short stretches of DNA that have a specific sequence of nucleotides. In
contrast to a bacterial chromosome, a eukaryotic
chromosome may have hundreds or even a few thousand
replication origins.
44. 44
https://plantlet.org/post-transcriptional-modification/
Capping of the pre-mRNA
involves the addition of 7-
methylguanosine (m7G) to the 5'
end. To achieve this, the terminal 5'
phosphate requires removal, which
is done with the aid of a
phosphatase enzyme. The enzyme
guanosyl transferase then catalyses
the reaction, which produces the
diphosphate 5' end.
