Ch. 3 Questions

Discuss two reasons why the therapeutic use of embryonic stem cells can present a problem.

Because of their capacity to divide and differentiate into specialized cells, stem cells offer a potential treatment for diseases such as diabetes and heart disease Cell-based therapy refers to treatment in which stem cells induced to differentiate in a growth dish are injected into a patient to repair damaged or destroyed cells or tissues. Many obstacles must be overcome for the application of cell-based therapy. Although embryonic stem cells have a nearly unlimited range of differentiation potential, they are seen as foreign by the patient's immune system and may trigger rejection. Also, the destruction of embryos to isolate embryonic stem cells raises considerable ethical and legal questions.

Explain in your own words why DNA replication is said to be "semiconservative"?

DNA replication is said to be semiconservative because, after replication is complete, one of the two parent DNA strands makes up half of each new DNA molecule. The other half is a newly synthesized strand. Therefore, half ("semi") of each daughter DNA molecule is from the parent molecule and half is a new molecule.

What structures form during pro-phase? (Mitosis)

During pro-phase, each chromosome becomes visible with its identical partner attached, forming the familiar X-shape of sister chromatids.

What separates the base pair at the start of DNA replication?

Special enzymes, including helicase, untwist and separate the two strands of DNA.

Place the following structures in order form least to most complex organization: chromatin, nucleosome, DNA, chromosome. a. DNA, nucleosome, chromatin, chromosome b. nucleosome, DNA, chromosome, chromatin c. DNA, chromatin, nucleosome, chromosome d. nucleosome, chromatin, DNA, chromosome

a. DNA, nucleosome, chromatin, chromosome

Which of the following is a feature common to all three components of the cytoskeleton? a. They all serve to scaffold the organelles within the cell. b. They are all characterized by roughly the same diameter. c. They are all polymers of protein subunits. d. They all help the cell resist compression and tension.

a. They all serve to scaffold the organelles within the cell.

Transcript and translation take place in the ____________ and ____________, respectively. a. nucleus; cytoplasm b. nucleolus; nucleus c. nucleolus; cytoplasm d. cytoplasms nucleus

a. nucleus; cytoplasm

Which of the following is a function of the rough ER? a. production of proteins b. detoxification of certain substances c. synthesis of steroid hormones d. regulation of intracellular calcium concentration

a. production of proteins

The nucleus and mitochondria share which of the following features? a. protein-lined membrane pores b. a double cell membrane c. the synthesis of ribosomes d. the production of cellular energy

a. protein-lined membrane pores

Which of the following is part of the elongation step of DNA synthesis? a. pulling apart two DNA strands b. attaching complementary nucleotides to template strands c. untwisting the DNA helix d. none of the above

b. attaching complementary nucleotides to template strands

Because they are embedded within the membrane, ion channels are examples of _____________. a. receptor proteins b. integral proteins c. peripheral protein d. glycoproteins

b. integral protein

Choose the answer that best completes the following analogy: Diffusion is to __________ as endocytosis is to ___________. a. filtration; phagocytosis b. osmosis; pinocytosis c. solutes; fluid d. gradient; chemical energy

b. osmosis; pinocytosis

The rough ER has its name due to what associated structures? a. Golgi apparatus b. ribosomes c. lysosomes d. proteins

b. ribosomes

What is a primary function of tumor suppressor genes? a. stop all cells from dividing b. stop certain cells from dividing c. help oncogenes produce oncoproteins d. allow the cell to skip certain phases of the cell cycle

b. stop certain cells from dividing

Ion pumps and phagocytes are both examples of __________. a. endocytosis b. passive transport c. active transport d. facilitated diffusion

c. active transport

What multipoint stem cells from children sometimes banked by parents? a. fetal stem cells b. embryonic stem cells c. cells from the umbilical cord and from baby teeth d. hematopoietic stem cells from red and white blood cells

c. cells from the umbilical cord and from baby teeth

Which type of stem cell gives rise to red and white blood cells? a. endothelial b. epithelial c. hematopoietic d. mesenchymal

c. hematopoietic

Which of the following structures could be found within the nucleolus? a. chromatin b. histones c. ribosomes d. nucleosomes

c. ribosomes

Which of the following phases is characterized by preparation for DNA synthesis? a. G0 b. G1 c. G2 d. S

d. S

A mutation in the gene for a cyclin protein might result in which of the following? a. a cell with additional genetic material than normal b. cancer c. a cell with less genetic material than normal d. any of the above

d. any of the above

The diffusion of substances within a solution tends to move those substances _________ their ___________ gradient. a. up; electrical b. up; electrochemical c. down; pressure d. down; concentration

d. down; concentration

Arrange the following terms in order of increasing specialization: oligopotency, pleuripotency, unipotency, multipotency. a. m, p, o, u b. p, o, m, u c. o, p, u, m d. p, m, o, u

d. pleuripotency, multipotency, oligopotency, unipotency

Which of the following is not made out of RNA? a. the carriers that shuffle amino acids to a growing polypeptide strand b. the ribosome c. the messenger molecule that provides the code for protein synthesis d. the intron

d. the intron

Choose the term that best completes the following analogy: Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to _________________. a. the walls of the pool b. the chlorine c. the flotation toys d. the water

d. the water

What are cyclins and cyclin-dependent kinases, and how do they interact?

A cyclin is a class of cell cycle control molecules. It works together with a group of molecules known as cyclin dependent kinase (CDK) which determines the progression of cell through checkpoints.

Explain how a transcription factor ultimately determines whether or not a protein will be present in a given cell?

A transcription factor is one of a class of proteins that bind to specific genes on the DNA molecule and either promote or inhibit their transcription. Transcription Factors Regulate Gene Expression. While each body cell contains the organism's entire genome, different cells regulate gene expression with the use of various transcription factors. Transcription factors are proteins that affect the binding of RNA polymerase to a particular gene on the DNA molecule.

How does temperature affect diffusion rate, and why?

Diffusion occurs more quickly in hot temperatures as opposed to cold.

Explain why the structure of the ER, mitochondria, and Golgi apparatus assist their respective functions.

For the rough ER, the ribosomes play a role in protein synthesis. Mitochondria is the power house of the cell. The bean-shape allows it room to have nuclei and create ATP. The Golgi apparatus's shape is the "post office" for the cell, and it's winding shape makes it perfect fro it's function of packaging and shipping material.

What happens to the small and large ribosomal sub-units at the end of translation?

In translation, the tRNA brings the necessary amino acids into the sequence, allowing the mRNA to make a codon. The tRNA then provides an anti-codon and the cycle continues until there is a "stop" signaled. This is then translated into a new protein product.

Compare and contrast lysosomes with peroxisomes: name at least two similarities and one difference.

Lysosomes and peroxisomes both contain enzymes and can break down materials. They differ because peroxisomes "neutralize" while lysosomes "destroy".

What materials can easily diffuse through the lipid bilayer, and why?

Small, non polar materials, such as oxygen and carbon dioxide gases are able to pass through the lipid bilayer because the tails are non polar.

Why is it so important that DNA replication takes place before cell division? What would happen if cell division of a body cell took place without DNA replication, or when DNA replication was incomplete?

So, it is important that the replication takes place before cell division. In case of cell division without the replication of DNA, the daughter cells will not receive any template DNA form the parent. ... Such cells, without of genetic material will die due to the lack of genome.

What is the primary role of the endomembrane system?

The primary role of the endomembrane system is to divide cells into different compartments, protein synthesis, protein transport, lipid movement and metabolism, and detoxification of poisons.

Briefly explain the similarities between transcription and DNA replication.

Transcription and DNA replication both involve making copies of the DNA in a cell. Transcription copies the DNA into RNA, while replication makes another copy of DNA. ... Although DNA and RNA have some chemical similarities, each molecule performs different functions in living organisms.Mar 13, 2018

Contrast transcription and translation. Name at least three differences between the two processes.

Transcription is the synthesis of RNA from a DNA template where the code in the DNA is converted into a complementary RNA code. Translation is the synthesis of a protein from an mRNA template where the code in the mRNA is converted into an amino acid sequence in a protein. Transcription: 1.

Why is receptor-mediated endometriosis said to be more selective than phagocytosis or pinocytosis?

While phagocytosis and pinocytosis are typically not highly selective, receptor-mediated endocytosis is very selective. When external receptors bind a specific ligand, the cell responds by endocytosing the ligand.

Which of the following organelles produces large quantities of ATP when both glucose and oxygen are available to the cell? a. mitochondria b. peroxisomes c. lysosomes d. ER

a. mitochondria

How many "letters" of an RNA molecule, in sequence, does it take to provide the code for a single amino acid? a. 1 b. 2 c. 3 d. 4

c. 3

Which of the following sequences on a DNA molecule would be complementary to GCTTATAT? a. TAGGCGCG b. ATCCGCGC c. CGAATATA d. TGCCTCTC

c. CGAATATA

Which of the following is not a difference between DNA and RNA? a. DNA contains thymine whereas RNA contains uracil b. DNA contains deoxyribose and RNA contains ribose c. DNA contains alternating sugar-phosphate molecules whereas RNA does not contain sugars d. RNA is single stranded and DNA is double stranded

c. DNA contains alternating sugar-phosphate molecules whereas RNA doe snot contain sugars

What would happen if anaphase proceeded even though the sister chromatids were not properly attached to the respective microtubules and lined up at the metaphase plate?

One or both of the new daughter cells would accidently receive duplicate chromosomes and/or would be missing certain chromosomes.

What do osmosis, diffusion, filtration, and the movement of ions away from like charge all have in common? In what way do they differ?

Osmosis, diffusion, filtration, and the movement of ions away from like charges all follow a concentration gradient, either from high to low or low to high. They differ by their processes.