Cellular and molecular basis of inheritance Flashcards
What is a chromosome?
An entire chain of DNA along with a group of stabilizing proteins. Humans typically have 23 pairs in each of their cells
Explain chromosome structure and organization.
DNA strands are wrapped around protein structures called histones, forming DNA-Histone complexes called “Nucleosomes”. Each one contains about 8 histones and 146 base pairs. This under goes additional supercoiling until the chromosome is formed.
What is a cell?
A cell is defined as the fundamental, structural and functional unit of all living organisms
What is a prokaryote?
A prokaryote is a single-celled organism that lacks a nucleus, and other membrane-bound organelles. However not all prokaryotes are unicellular
What is a eukaryote?
Eukaryotes are organisms whose cells have a nucleus enclosed within a nuclear envelope.
What are the criteria for multicellular organisms?
The four essential processes by which a multicellular organism is made: cell proliferation, cell specialization, cell interaction, and cell movement
How many genes are in the human genome?
20,000
Explain the major and minor grooves of DNA.
The DNA has 2 grooves which are not equal in size because of the geometry of the base pair. The angle between the two sugars is about 120 to 240 degrees.
The major groove
How many types of RNA are there? Explain their functions.
mRNA: carries copies of the genetic instructions from DNA to other parts of the cell.
rRNA: Together with proteins, composes the ribosome, the organelles that are the site of protein synthesis.
tRNA: Brings the correct amino acid to the ribosome during translation.
Explain the major and minor grooves of DNA.
The DNA has 2 grooves which are not equal in size because of the geometry of the base pair. The angle between the two sugars is about 120 to 240 degrees.
The major groove occurs where the backbones are far apart, the minor groove occurs where they are close together. The grooves twist around the molecule on opposite sides.
The grooves separate the two sugar-phosphate backbones from each other and the atoms exposed in the grooves are accessible to the solvent and to interactions with proteins.
How many types of DNA conformations are there? Describe them.
There are three types
A-DNA: It is a right-handed double helix similar to the B-DNA form.
B-DNA: This is the most common DNA conformation and is a right-handed helix.
Z-DNA: Z-DNA is a left-handed DNA where the double helix winds to the left in a zig-zag pattern.
Define the central dogma of molecular biology.
What is the central dogma of molecular biology explain its meaning?
The central dogma of molecular biology states that DNA contains instructions for making a protein, which are copied by RNA. RNA then uses the instructions to make a protein.
Describe the gene structure in eukaryotic cells.
Most eukaryotic genes contain segments of coding sequences (exons) interrupted by noncoding sequences (introns). Both exons and introns are transcribed to yield a long primary RNA transcript.
Explain transcription and translation.
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference, or template.
Translation is the process through which information encoded in messenger RNA (mRNA) directs the addition of amino acids during protein synthesis.
