Cell Biology Answers

The Cambrian explosion was
a sudden increase in new species that challenges the fundamental correctness of evolution.
the asteroid impact near the Yucatan Peninsula that likely caused a mass extinction of dinosaurs and other species.
the sudden diversification of animal life from simple organisms to all the basic body types known today
the sudden appearance of dinosaurs in the fossil record during the Cambrian period.

Which of the following describes how neurons use neurotransmitters to communicate with one another?
At synapses, dendrites release neurotransmitters that are recognized by proteins on axons.
At synapses, axons release neurotransmitters that are recognized by proteins on dendrites.
Axons fuse with dendrites to produce a continuous cellular body that allows neurotransmitters to flow from one neuron to another.
The axons of one neuron connect to the axons of another neuron to relay information through neurotransmitter release.

The study of biology can be understood through the organizational hierarchy of life. Each level of life builds upon the next level, and this increasing complexity is what leads from molecules up to an entire ecosystem. How is the tissue level different from the other levels of life?
A tissue is an individual living thing, such as a bacterium, fungus, protist, plant, or animal.
A tissue is a group of similar cells that work together to perform a function.
A tissue is a group of multiple organs that work together to perform vital functions for the organism.
A tissue is a collection of molecules and reactions that form the basic unit of all living things.

What is the function of Hox genes during development?
maintain pluripotency in embryonic stem cells
promote cleavage in the early embryo
encode enzymes that provide cellular energy for the developing embryo
direct the formation of the appropriate structure at a given location in the embryo

After an mRNA strand has been transcribed from DNA, it must be processed before translation can take place. Which of the following statements are true about the RNA editing process?
Additional amino acids are added before translation occurs,
noncoding segments are removed and exons are joined together,
a cap is added to one end of the mRNA,
editing occurs in the cytosol as the new mRNA strand leaves the nucleus. (more than one answer)


Which statement describes an operon?
Heritable changes in gene expression that occur without altering the DNA sequence,
mRNA modifications, such as the addition of a 5\'-cap and 3\' poly-A tail and the removal of introns,
a gene cluster controlled by a single promoter that transcribes to a single mRNA strand,
the processing of exons in mRNA that results in a single gene coding for multiple proteins,
protein modifications, such as the addition of a functional group, or alternate folding of the protein

Intracellular receptors are located in either the cytoplasm or the nucleus. Which type of ligands binds to intracellular receptors? small hydrophobic molecules, large water soluble molecules, small water soluble molecules, or large polar molecules.

Select the description of an exon - noncoding portion of a DNA sequence that is removed from pre mRNA, altered guanine nucleotide added to the front of pre-mRNA, portion of a DNA sequence that is not removed from pre-mRNA and is expressed in the protein, or sequence of adenine nucleotides added onto the end of pre-mRNA.

What are respirasomes? What is their function?

9+2 structure in fibres is common in certain?
a.cilia b.flagella c. eukaryotes d.bacteria e. all

What is isotonic and isometric contraction?

) Arrangement of steps of DNa replication in order wise. is this correct


1.- Helicase unwinds the DNA double helix

2.- single stranded DNA binding proteins bind to each template strand.

3.- RNA primers are added.

4.- DNA polymerase synthesizes DNA.

5.- RNA primers are removed.

6.- DNA ligase joins DNA fragments together.

What strategies do cells use to ensure that newly replicated DNA does not contain errors? (more than one answer)

DNA polymerase replaces the newly replicated DNA on any chromosomes on which there are mistakes.

Enzymes proofread the DNA after the DNA has been replicated and replace any mismatched nucleotides.

Enzymes repair mistakes in the new DNA double helix after the new double helix separates from the original double helix.

As DNA polymerase synthesizes new DNA, the DNA polymerase finds and corrects misplaced nucleotides

Enzymes remove and resynthesize any misshapen sequences in the DNA prior to replication.

I believe the answer would be these choices - I they correct would their be any others

As DNA polymerase synthesizes new DNA, the DNA polymerase finds and corrects misplaced nucleotide.

Enzymes proofread the DNA after the DNA has been replicated and replace any mismatched nucleotide.

How does the structure of DNA encode genetic information?
the sequence of amino acids
the sequence of bases
the structure of the bases
the length of the DNA molecule

What is the key feature of DNA that allows it to be copied?
the arrangement of chromosomes
the sugar phosphate backbone
complementary base pairing
Okazaki fragments