exam 2 sample q's

Question 1

transcription factor

Answer 1

protein that promotes transcription

Question 2

chromatin

Answer 2

mixture of DNA and proteins that form the chromosomes

Question 3

chromosome

Answer 3

long DNA molecule with part of all of the genetic material in an organism. Single stranded form of condensed chromatin

Question 4

sister chromatid

Answer 4

duplictaed copes of a single chromsoome that are attached to each other and are identical

Question 5

independent assortment

Answer 5

alleles of two or more differebt gametes assorted into gametes indednet of one another. this si why offspring siblings will look different from each other. when cells divide during meiosis, homologous chromsoomes are randomly distributed to daughter cells

Question 6

exon

Answer 6

coding sections of RNA transcript or the DNA encoding it, that are translated into a protein.

EXONS ARE PARTS OF A GENE THAT CODE FOR A PROTEIN

Question 7

introns

Answer 7

nucelotide sequences in DNA adn RNA that do not code dreicly fot a protein

Question 8

anabolic pathway

Answer 8

metabolic pathway that consues energy from synthesis of large molecules from smaller ones

Question 9

catabolic pathway

Answer 9

metabolic pathway that releases energy from breaking down larger molecules into smaller ones

Question 10

List and define the metabolic modes observed in prokaryotes?

Answer 10

The modes present in prokaryotes are phoottrophs and chemotrophs. Phototrophs obtain energy from the sun and chemotrophs obtain energy from chemicals.

Question 11

List and define the metabolic modes observed in eukaryotes?

Answer 11

The modes found in euaryotes are photoautotrophs and chemoheterotrophs. Photoautotrophs carbon source is CO2 or related compounds and energy is obtained from the sun. Chemohererotropsh obtain energy from obtain energy from organic molecules and their carbon source is also organic molecules.

Question 12

What is the endosymbiont theory? What evidence supports the endosymbiont theory

Answer 12

The endosymbiont theory is the theory that mitochondria and plastids orginated as prokaryotic cells engulfed by a host cell. The engulfed cell and its host then evolved into single organisms. The evidence that supports it is: 1)mitochondria and chloroplasts have their own DNA, ribosomes and double membranes. 2)mitochondria and chloroplasts replicate by binary fission. 3)DNA similar to prokaryotes that had similar functions

Question 13

interphase

Answer 13

the phase tat is preparing the cell for division (mitosis). During interphase chromsoomes are duplicated. it consist of G1 which is metabplic growth and activity and S phase- it consist of metabolic growth and activity and DNA synthesisi. S phase is the part of interphase when chrosmomes are duplicated. G2 phase is metabolic growth and activity and its fully preparing the cell for dvisiion

Question 14

mitosis

Answer 14

the cell division. It results in diploid daughter cells which means that the two daughter cells are identical to each other and the parent cell

Question 15

subphases of mitosis

Answer 15

-prophase
-prometaphase
-metaphase
-anaphase
-telophase
-cytokinesis

Question 16

prophase

Answer 16

when the chromsomoes condense and the microtubules/spindles attach to each chromosome

Question 17

prometaphase

Answer 17

when the chromsomes further condense

Question 18

metaphase

Answer 18

when the chromsomes line up in the middle of the cell

Question 19

anaphase

Answer 19

when each chromatid is pulled aprt to opposite ends of the cell

Question 20

telophase

Answer 20

when te ncueli form on each side of the cell

Question 21

cytokinesis

Answer 21

final step- division of the cytoplasm

Question 22

What is crossing over? When does it occur? What does it result in

Answer 22

It is the exchange of genetic material between homologous chromosomes during phrophase I of meiosis result in a mix of parental characteristics in offspring.

Question 23

What is the composition (protein, mRNA, DNA) of the following components? Repressor, Transcription Factor, Operator, Promoter, Transcript, RNA polymerase, Ribosome, control elements

Answer 23

A repressor is a protein that inhibits transcription. A transcription factor is a protein that regulates the transcription of genes. Operator is DNA. Rrepressor molecule can bind to the operon and block RNA polymerase. Transcript is mRNA. RNA polyermase is a protein that aids in transcription. Ribosome is DNA, it synthesizes proteins. Control elements is DNA.It is elements of non coding DNA that serves as binding sites for transcription factors.

Question 24

Why is gene regulation important in prokaryotes? Unicellular eukaryotes? Multicellular eukaryotes?

Answer 24

Gene regulation is actually important in unicellular eukaryotes because to help with the response to cellular and environmental cues. Gene regulation is important in multi-cellular eukaryotes in compartmentalization. Compartmentalization in cells is the separation of the cell interior in distinct sections with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes. In multicellular eukaryotes, gene regulation also helps with the response to environmental cues as well.

Question 25

If bacteria are grown in medium without tryptophan present, what is the condition of the trp operon? If these bacteria are transferred to medium with tryptophan, what is the response of the trp operon?

Answer 25

If tryptophan is not present in the environment the bacterium needs tryptophan for synthesis of proetins. Then, if trp becomes present in the envornments the bacterium does not need tryptophan for protein sytnethsis. Representing trp operson saves energy required to synthesize the enzymes of the pathway to make trp.

Question 26

Explain why an anabolic pathway in prokaryotes is likely to be regulated by a repressible operon, but a catabolic pathway is regulated by an inducible operon.

Answer 26

Repressible operon represses transcription and an inducer blcoks the repressor and promotes transcription. With anabolic pathway, repressing the gene involved in biosynthesis when the end of the product is plentiful saves energy. With catabolic pathways inducing the genes involved in breaking down particular molecule only when that molecule is present saves energy.

Question 27

what is the difference between a repressible operon and inducible operon

Answer 27

repressible operon represses trancription and an inducible operon bloclks the repressor and promotes trancription

Question 28

Describe mRNA processing in a eukaryote. How is mRNA different in prokaryotes?

Answer 28

In eukaryotes transcription produces pre-mRNA molecule that can be processed into mature mRNA by the addition of a 5’ cap and a 3’ tail. mRNA in prokaryotes posses exons but does not have introns, while eukaryotic mRNA do have introns and exons.

Question 29

Compare these different forms of cell division- binary fission, mitosis, meiosis. Identify common features, major differences, and which cells perform each type of cell division.

Answer 29

Binary fission is when a single cell called the parent cell splits into two cells called daughter cells. Mitosis Is when two daughter cells are made from division that are identical to each other and the parent cell. It is diploid, two identical sets to each other and they are somatic. Meiosis is haploid. It is a process where a single cell divides twice to produce four cells containi g half the original amount of genetic information.

Question 30

What is the difference between euchromatin and heterochromatin? What process converts chromatin from one form to the other and how are these forms related to regulation of gene expression?

Answer 30

euchromaitn is loosely packed chromsoomes. heterochromatin is tightly packed chromsomes and the genes are ot usually expressed. the process that converts them from one form to another is chromatin modification -remember DNA methylation

Question 31

Distinguish between determination and differentiation during embryonic development.

Answer 31

Differntiation no precedes determination. Differentation is the process by which cells become specialized in structure and function. Determination is the process by which cells become specialized I structure and function. Determination also irreversibiky commits a cell to becoming a particular cell type.

Question 32

what is the function of homeotic genes?

Answer 32

they are the regulator gene that directs the development of particular body segments or structures

Question 33

Describe the role of cytoplasmic determinants in the induction of embryonic cells to undergo differentiation.

Answer 33

Cytoplasmic determinants come from the mother. They are maternal substances such as protein or mRNA, that when placed into an egg influences the course of early development by regulating expression of genes that affect developmental fate of cells. Induction is cells from one area of the embryo influence another via signals that affect gene expression.