1.1 The study of life Read Online
Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.
Question: in order to be successful, chemotherapy drugs have to stop cell division. The most likely method for this would be to:
Choices:
denature all the enzymes in the cell so division can't occur
stop cellular respiration so the cancerous cells don't have energy
interfere with the function of the spindle fibers so the chromosomes can't seperate
speed up the cell cycle in the canceerous
Question: A DNA sample from an organism reveals that it is composed of 30% thymine. What percentage of guanine does this organism have?
Choices:
30%
40%
20%
60%
Question: what is the definition of biotechnology?
Choices:
the production of genetically identical organisms, cells or DNA molecules
the study of living things
the study of interactions between organisms and their enviroment
the modification of organisms, cells and their molecules for practical benefits
Question: Typical causes of mutations include:
Choices:
radiations
spontaneous change
chemical toxins
all of these
Question: a point mutation will always cause:
Choices:
nucleotides to be removed from the DNA
one nucleotide to be changed in the DNA
a change to the amino acid
extra nucleotides to be added to the DNA
Question: all of the following are needed in a reproductive cloning procedure except:
Choices:
a sperm cell
a donor diploid cell
an empty egg cell
a surrogate mother
all of the above
Question: Blood cells and muscle cells make different proteins because:
Choices:
blood cells contain only the genes for making blood cell proteins and muscle cells only contain mucsle protein genes
they are not yet differentiated
all cells of an organism have the same genes, and express all of them
even though both have the same genes, they express different genes
Question: What is a clone?
Choices:
an exact genetic copy of an organism
a cell that can take up plasmids
an offspring produced by test-tube fertilization
a segment of DNA of specific length
Question: Embryonic stem cells (ESC's) from research can come from any of the following sources except
Choices:
therapeutic cloning (SCNT)
in vitro fertilization (TVF)
terminated pregnancies
ESC's can come from any of these sources
Question: Which statement best describes the difference between therapeutic and reproductive cloning?
Choices:
therapeutic cloning is used to produce stem cells for individuals which a medical condition while reproductive cloning is used to produce organisms identical to what they were cloned from
therapeutic cloning involves producing medications while reproductive cloning is used for in vitro fertilization procedures
there really aren't any differences between therapeutic and reproductive cloning
therapeutic cloning procedures cells that are not genetically identical to what they were taken from while reproductive cloning produces cells that are genetically identical to what they were taken from
Question: Which of the following is not a step of translation?
Choices:
transcribe
elongate
terminate
recognize