Exam 1: Introduction to the Study of Cell and Molecular Biology

The field of biological research in which biologists are attempting to create a living cell in the laboratory,essentially from scratch is known as __________.More modestly,this branch of biology also has a goal of developing novel life forms,beginning with existing organisms,that have a unique value in medicine,industry or in cleaning up the environment.

Wilhelm Roux performed an experiment in which he allowed a frog embryo to divide into two cells.He then killed one of the cells with a hot needle,but did not separate the cell he had killed from the remaining cell.The embryo developed abnormally,leading Roux to conclude that the cells in a developing embryo have their developmental potential restricted at each division,even the first.Driesch and others demonstrated that separation of cells in a number of embryos resulted in the development of two smaller,but normal,embryos.Which of these investigators is most likely to have made a procedural error in his experimental design and what was it?

You are studying an infectious agent,the effects of which resemble a virus.You isolate the agent and treat it with an enzyme that degrades proteins and it is unaffected.However,if treated with RNase,it loses its infectivity.What kind of pathogen is it most likely to be?

Why is it hoped that transplantation of stem cells may help humans who have heart disease?

What characteristics distinguish prokaryotic and eukaryotic cells?

Why are viruses not considered by most biologists to be living organisms?

You are conducting an experiment by trying to reproduce the work performed in 1891 by Hans Driesch,a German embryologist.You are working with a fertilized sea urchin egg and allow it to complete the first cell division after fertilization.You then carefully separate the two cells of the embryo and allow their development to continue.Based on Driesch's experiment,which result below would you expect to happen?

Why are adult stem cells an ideal system for cell replacement therapies?

A virus infects a cell that has been placed in culture.The cell grows into a clone of cells with no apparent infection.Three months later,the cells are exposed to ultraviolet light.Shortly thereafter,most of the cells lyse and shed large amounts of virus.What kind of infection is this? What kind of infection results in a loss of growth control at some time after infection?

You are studying a virus.It has an icosahedral protein capsid and is surrounded by a lipid-containing envelope.What kind of organism does the virus infect?

Despite being correct about the first two tenets of the Cell Theory,Schleiden and Schwann made an error about another central feature of cells.What was their error?

Virtually all chemical changes that take place in cells require ________,molecules that greatly increase the rate at which a chemical reaction occurs.

The collection of bacteria that live on and within the human body are being isolated,identified and characterized;they are referred to as the human ______.It has been demonstrated that these organisms differ based upon the age,diet,geography and state of health of the human from which they were obtained.

Bacteria often live in complex,multi-species communities,like the layer of plaque that grows on your teeth;such a community is called a(n)_________.

The apical ends of intestinal cells face the intestinal channel and have long processes that facilitate the absorption of nutrients.What is the name of these processes and what cytoskeletal element forms their internal skeleton?

A high powered microscope that allows investigators to examine the detailed surfaces of cells is called a ___________.

What cells are likely to be the first used in human trials using ES cells for cell replacement therapy and what do these cells do? What have researchers had to do to get these cells to differentiate in culture? What happened when these human cells were transplanted into rats with paralyzing spinal cord injuries?

Bacteria will often pass a piece of DNA from a donor bacterial cell to a recipient bacterial cell presumably through a structure called a pilus.What is this process called?

Which of the following characteristics is(are)a basic property of cells?

The genetic material of a prokaryotic cell is present in a _________,a poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm.