Week 17 / Protein Synthesis and Cell Cycle 1 Flashcards
What is the role of DNA in protein synthesis?
DNA is used as a template for the synthesis of specific proteins.
What is transcription?
It is the process where information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA.
What is the product of transcription?
A specific molecule of RNA (ribonucleic acid).
What is translation?
where RNA attaches to a ribosome, and the information in the RNA is translated into a sequence of amino acids to form a new protein.
Where does translation occur?
At the ribosome.
What is the end result of translation?
A new protein molecule is formed.
What is the purpose of chemical synthesis in cells?
To maintain homeostasis.
Why is much of a cell’s machinery dedicated to synthesizing proteins?
To produce a large number of diverse proteins needed for cellular functions.
What role do proteins play in determining a cell’s characteristics?
Proteins determine the physical and chemical characteristics of cells.
Name a structural role of proteins in cells.
Proteins help assemble cellular structures such as the plasma membrane, the cytoskeleton, and organelles.
List three functional roles of proteins in the body.
- Hormones: Regulate bodily functions.
- Antibodies: Defend against pathogens.
- Contractile elements: Enable muscle movement.
How do proteins act as enzymes?
They regulate the rates of numerous chemical reactions in cells.
What is the role of transport proteins?
They carry various materials in the blood.
What happens during transcription?
Three types of RNA are made from the DNA template.
What is the role of messenger RNA (mRNA)?
mRNA directs the synthesis of a protein.
What is the function of ribosomal RNA (rRNA)?
rRNA joins with ribosomal proteins to make ribosomes.
What does transfer RNA (tRNA) do during protein synthesis?
tRNA binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation.
How many types of RNA are involved in transcription?
Three: mRNA, rRNA, and tRNA.
What is the role of miRNA
Regulate gene expression
Which enzyme catalyzes the transcription of DNA?
RNA polymerase.
How many DNA strands serve as a template during transcription?
Only one of the two DNA strands serves as a template.
What is the segment of DNA called where transcription begins?
The promoter, a special nucleotide sequence.
How do bases pair during transcription?
A: Bases pair in a complementary manner.
What is the segment of DNA called where transcription ends?
The terminator, a special end sequence.
What does the nucleotide sequence in an mRNA molecule specify?
The amino acid sequence of a protein.
Where does translation occur in the cell?
At ribosomes in the cytoplasm.
What is the role of the small ribosomal subunit in translation?
It has a binding site for mRNA.
What are the binding sites on the large ribosomal subunit?
The P site and the A site, which bind tRNA molecules.
What happens at the P site during translation?
The first tRNA molecule bearing a specific amino acid attaches to the mRNA at the P site.
What happens at the A site during translation?
The next tRNA molecule binds to the mRNA at the A site, preparing for amino acid incorporation.
During transcription, which RNA base pairs with the DNA base adenine (A)?
Uracil (U).
During transcription, which RNA base pairs with the DNA base thymine (T)?
Adenine (A).
During transcription, which RNA base pairs with the DNA base guanine (G)?
Cytosine (C).
During transcription, which RNA base pairs with the DNA base cytosine (C)?
Guanine (G).
What replaces thymine (T) in RNA during transcription?
Uracil (U).
What is the relationship between template DNA and complementary RNA?
The RNA sequence is complementary to the DNA template sequence.
What is cell division?
A: The process by which the human body generates new cells.
What are the two types of cell division?
Somatic cell division and reproductive cell division.
What is a somatic cell?
Any cell of the body other than a germ cell.
What are the two divisions involved in somatic cell division?
Mitosis: Nuclear division.
Cytokinesis: Cytoplasmic division.
What is the purpose of somatic cell division?
To replace dead or injured cells and add new cells during tissue growth.
What is the purpose of reproductive cell division?
To produce gametes, the cells needed for forming the next generation in sexually reproducing organisms.
What type of division occurs in reproductive cell division?
A special two-step process called meiosis.
What happens to the number of chromosomes during meiosis?
The number of chromosomes in the nucleus is reduced by half.
What is the cell cycle?
An orderly sequence of events in which a somatic cell duplicates its contents and divides into two.
Why is meiosis important for sexually reproducing organisms?
It ensures gametes have half the chromosome number, allowing for genetic diversity when gametes combine during fertilization.
How many chromosomes do human somatic cells contain?
23 pairs of chromosomes, for a total of 46.
Where do the chromosomes in a somatic cell come from?
One member of each pair is inherited from each parent.
What are homologous chromosomes?
Chromosomes that make up each pair, containing similar genes arranged in the same or almost the same order.
Which types of human cells undergo somatic cell division?
Cells in the brain, stomach, kidneys, and other parts of the body, excluding germ cells.
What is the exception to homologous chromosome pairs in somatic cells?
he sex chromosomes (X and Y).
What are the sex chromosomes in females?
What are the sex chromosomes in males?
Two large X chromosomes (XX).
One large X chromosome and a much smaller Y chromosome (XY).
Why are somatic cells called diploid cells?
They contain two sets of chromosomes, symbolized as 2n.
What are the two major periods of the cell cycle?
Interphase: When the cell is not
dividing.
Mitotic (M) Phase: When the cell is
dividing.
What happens during interphase in the cell cycle?
The cell grows and prepares for division.
Describe the stages of cell cycle
Interphase :
G1: Growth
S: Growth and DNA synthesis
G2: Growth and Final preparations for division
Mitotic phase:
Mitosis : Prophase,Metaphase, Anaphase,Telophase
Cytokinesis
