Exam 1

Question 1

What is regulating gene expression and why is it important?

Answer 1

Regulating gene expression controls when and how specific genes are expressed. This allows for proper development of cells, organs, and systems, and adaptation to changes in the environment. It also prevents diseases and disorders such as cancer.

Question 2

What is a transcription factor and how does it regulate gene expression?

Answer 2

A transcription factor is a protein that binds to specific DNA sequences and controls the rate of transcription of genes into RNA. This controls the amount of protein produced from a gene, affecting the phenotype of the cell or organism.

Question 3

What are iPSCs?

Answer 3

Induced pluripotent stem cells, adult cells that have been genetically reprogrammed to an embryonic stem cell-like state with the ability to differentiate into any type of cell in the body.

Question 4

What are the potential uses of iPSCs?

Answer 4

Treating human genetic conditions by creating patient-specific cells, and understanding genetic conditions in a more personalized manner.

Question 5

What is the role of transcription factors in making iPSCs?

Answer 5

Transcription factors are responsible for reprogramming adult cells back to a pluripotent state by introducing specific transcription factors like Oct4, Sox2, Klf4, and c-Myc.

Question 6

How are iPSCs made?

Answer 6

iPSCs are made by introducing specific transcription factors into adult cells, such as skin cells, via viral vectors or other methods, causing the cell’s genome to change, allowing it to become pluripotent.

Question 7

What is the basic unit of life?

Answer 7

Cells

Question 8

What are the components of a cell?

Answer 8

Cell membrane, cytoskeleton, cytoplasm, nucleus, mitochondria, endoplasmic reticulum (ER) and Golgi apparatus, ribosomes, lysosomes

Question 9

What are the general functions of major cellular organelles?

Answer 9

Cell membrane: selectively permeable barrier that surrounds the cell and controls the movement of materials in and out of the cell. Cytoskeleton: network of protein fibers that provide structural support and shape to the cell. Cytoplasm: gel-like substance that fills the cell and contains all the cell’s organelles. Nucleus: contains the cell’s genetic material and controls the cell’s growth and reproduction. Mitochondria: site of cellular respiration, which generates energy for the cell. Endoplasmic reticulum (ER) and Golgi apparatus: organelles responsible for protein synthesis and processing. Ribosomes: site of protein synthesis. Lysosomes: cell organelles that contain enzymes for breaking down and recycling cellular waste products.

Question 10

What is the cellular basis of disease?

Answer 10

Alteration of the normal functioning of cells, caused by genetic mutations, environmental factors, or infectious agents.

Question 11

What are the differences between somatic cells and germ cells?

Answer 11

Somatic cells are any cells of the body other than the reproductive cells (germ cells). Germ cells are the reproductive cells, such as eggs and sperm, that give rise to the next generation.

Question 12

What is the genetic information of an organism organized into?

Answer 12

The genetic information of an organism is organized into DNA molecules, which are made up of nucleotides. The DNA is organized into chromosomes, which are long, linear structures made up of DNA and proteins. The chromosomes are found in the nucleus of a cell and the complete set of chromosomes in a cell is called the genome.

Question 13

What is ploidy?

Answer 13

Ploidy refers to the number of sets of chromosomes in a cell. Haploid cells have one set of chromosomes (n), diploid cells have two sets of chromosomes (2n), and so on. This relates to the number of homologs of each chromosome because each chromosome has a homologous partner, and the number of homologous pairs present in a cell is determined by the ploidy level.

Question 14

What is the correct ploidy for human somatic cells?

Answer 14

The correct ploidy for human somatic cells is diploid (2n).

Question 15

What is the correct ploidy for human germ cells?

Answer 15

The correct ploidy for human germ cells is haploid (n).

Question 16

What is the relationship between phenotype and genotype?

Answer 16

The relationship between phenotype and genotype is that the phenotype is the observable characteristics of an organism and the genotype is the genetic makeup of an organism. Phenotype is determined by the genotype and the environment.

Question 17

What is a gene?

Answer 17

A gene is a segment of DNA that codes for a specific trait or characteristic, such as eye color or blood type.

Question 18

What is an allele?

Answer 18

An allele is a variant of a gene. Recessive alleles are not expressed when a dominant allele is present. Dominant alleles are always expressed, even when a recessive allele is present.

Question 19

What are chromosomes?

Answer 19

Chromosomes are the structures in the nucleus of a cell that carry genetic information. Replicated chromosomes are identical copies of a single chromosome. Sister chromatids are the identical copies of a chromosome that are joined at a centromere. Homologous chromosomes are pairs of chromosomes that carry the same genes in the same order, but may have different versions of those genes (alleles).

Question 20

What is the cell cycle?

Answer 20

The cell cycle is the series of events that occur in a cell leading to its division and duplication (replication). The major phases of the somatic cell cycle are: interphase (G1, S, G2) and the mitotic phase (M).

Question 21

What is mitosis?

Answer 21

Mitosis is the process by which a single cell divides to produce two identical daughter cells. It is a continuous process that can be divided into four main stages: prophase, metaphase, anaphase, and telophase. In prophase, the chromatin condenses into visible chromosomes. In metaphase, the chromosomes line up at the center of the cell. In anaphase, the sister chromatids separate and are pulled to opposite poles of the cell. In telophase, the chromosomes reach the opposite poles of the cell and decondense back into chromatin. Mitosis is important for a number of biological processes, including cell growth and repair, tissue regeneration, and the maintenance of chromosome number during cell division.

Question 22

What is the “central dogma” of genetic information transfer?

Answer 22

The “central dogma” is a fundamental concept in molecular biology that describes the flow of genetic information in living organisms. It states that DNA is transcribed into RNA, which is then translated into proteins, and the flow is unidirectional, meaning that information cannot flow from protein to RNA to DNA.

Question 23

What is transcription?

Answer 23

Transcription is the process by which the genetic information stored in DNA is used to make a complementary RNA molecule. It occurs in the nucleus of a cell and involves the enzymes RNA polymerase and several other transcription factors.

Question 24

What is the role of RNA processing after transcription?

Answer 24

After transcription, the RNA transcript goes through processing steps, including capping and polyadenylation, that modify the ends of the transcript and protect it from degradation. Also, non-coding sequences called introns are removed and the coding sequences called exons are spliced together to form a mature mRNA.

Question 25

How does the generation of a protein from DNA relate to the phenotype of an organism?

Answer 25

The generation of a protein from DNA is a crucial step in the relationship between genotype (the genetic makeup of an organism) and phenotype (the observable characteristics of an organism). The genetic information stored in DNA is used to make proteins, which perform most of the functions in cells, and ultimately determine the characteristics of an organism.

Question 26

What is the difference between the DNA sequence and the final mRNA sequence?

Answer 26

The DNA sequence is the genetic code that contains all the instructions for the production of an organism. The final mRNA sequence is a copy of a portion of the DNA code, containing the instructions for the synthesis of a specific protein. The DNA sequence is transcribed into an RNA sequence, which is then translated into a protein. The final mRNA sequence will have thymine replaced with uracil and will not contain introns.

Question 27

What is the process of translation?

Answer 27

Translation is the process by which the genetic information encoded in RNA is used to synthesize a protein. It occurs in the ribosomes, which are located in the cytoplasm of a cell. The process of translation involves three main steps: initiation, elongation, and termination.

Question 28

What is the genetic code?

Answer 28

The genetic code is the set of rules by which the sequence of nucleotides in DNA and RNA molecules is translated into the sequence of amino acids in proteins. The code is composed of codons, which are sequences of three nucleotides that specify a single amino acid.

Question 29

How can specific changes in the DNA or RNA sequence affect the resulting protein?

Answer 29

Specific changes in the DNA or RNA sequence, such as point mutations, can affect the resulting protein in a number of ways. For example, a point mutation that changes a codon that specifies a specific amino acid to a codon that specifies a different amino acid will change the amino acid in the resulting protein. This can result in a protein that is non-functional or has reduced activity.

Question 30

What is gene expression and why is it important?

Answer 30

Gene expression is the process by which the genetic information in DNA is converted into functional molecules, such as proteins, that carry out specific cellular functions. This process involves the transcription of DNA into RNA, which is then translated into a protein. Gene expression is important for development and cellular diversity within a single organism because it allows cells to differentiate and take on specific roles.

Question 31

What is chromatin and what role does it play in regulating gene expression?

Answer 31

Chromatin is the complex of DNA and proteins that make up the chromosomes in eukaryotic cells. It is composed of DNA wrapped around histone proteins, which helps to package the DNA into a compact structure. Chromatin structure plays an important role in regulating gene expression by inhibiting the access of the transcription machinery to the DNA.

Question 32

What are transcription factors and how do they regulate gene expression?

Answer 32

Transcription factors are proteins that bind to specific sequences on the DNA and promote or inhibit the transcription of a gene. They are important for regulating the expression of genes at the right time and place in the cell and organism.

Question 33

What are induced pluripotent stem cells (iPSCs)?

Answer 33

Induced pluripotent stem cells (iPSCs) are adult cells that have been reprogrammed to an embryonic stem cell-like state by the forced expression of specific transcription factors such as Oct4, Sox2, Klf4 and c-Myc. This process of reprogramming cells by regulating transcription is important for producing iPSCs, which have potential applications in regenerative medicine and disease modeling.

Question 34

What is the blastocyst and what are the different cell types that make it up?

Answer 34

The blastocyst is an early stage of embryonic development in mammals, including humans. It is a ball of cells that forms in the first week after fertilization of an egg. The blastocyst has three distinct cell types: the inner cell mass, the trophectoderm, and the fluid-filled cavity called the blastocoel.

Question 35

What are totipotent cells and where are they found in the body?

Answer 35

Totipotent cells are cells that have the ability to differentiate into any cell type in the body. They are found in the inner cell mass of the blastocyst stage of embryonic development in mammals.

Question 36

What signals the initiation of transcription?

Answer 36

The promoter in the DNA signals the initiation of transcription.

Question 37

Where does transcription occur?

Answer 37

Transcription occurs within the nucleus.

Question 38

What is the role of the promoter in DNA?

Answer 38

The promoter is a specific sequence of DNA that signals to the RNA polymerase enzyme where to start transcribing the DNA into RNA.

Question 39

What is the purpose of the 5' cap and 3' poly-A tail added to mRNA?

Answer 39

The 5' cap and 3' poly-A tail help protect the mRNA from degradation and aid in the efficient translation of the mRNA into a protein.

Question 40

What is the role of introns and exons in post-transcriptional modification?

Answer 40

Introns are removed and exons are spliced together during post-transcriptional modification.

Question 41

What is the process of gene expression also known as?

Answer 41

The process of gene expression is also known as the "central dogma" of molecular biology.

Question 42

What are the three main steps in the process of gene expression?

Answer 42

The three main steps in the process of gene expression are transcription, translation, and post-transcriptional modification.

Question 43

What is the difference between the coding strand and template strand of DNA?

Answer 43

The coding strand is the strand of DNA that contains the information needed to code for a specific protein, while the template strand serves as a template for the synthesis of a complementary RNA molecule during transcription. The coding strand is read during translation, while the template strand is read during transcription.