Exam 3 (Ch 9-13)

Question 1

what happens in G1 phase of interphase?

Answer 1

• Cell recovery from previous split
• doubles organelles
• grows in size

Question 2

what happens in S phase of interphase

Answer 2

• DNA synthesis and replication
• chromosomes leave S phase with 2 identical sister chromatids

Question 3

phases of Mitosis

Answer 3

Prophase, Metaphase, Anaphase, and Telophase

Question 4

what are the specialized microtubules that connect sister chromatids

Answer 4

Kinetochores

Question 5

what is cytokinesis

Answer 5

division of the cytoplasm

Question 6

cytokinesis in animal cells

Answer 6

a cleavage furrow forms between the daughter nuclei in telophase
- “pulling on a drawstring”

Question 7

cytokinesis in plant cells

Answer 7

a cell plate forms

Question 8

what is a compound (normally a protein) that influences the activities of a cell?
- internal and external

Answer 8

Signal

Question 9

An example of an external signal

Answer 9

growth factors received at the cells plasma membrane

Question 10

example of an internal signal

Answer 10

regulatory proteins, called cyclins, increase and decrease as the cell cycle continues

Question 11

what is the positive regulator that promotes the cell cycle by making regulatory proteins that tell the cell to start S phase?

Answer 11

Proto-oncogenes

Question 12

what is the negative regulator that codes for regulatory proteins that inhibit the cell cycle

Answer 12

Tumor-suppressor genes

Question 13

what is programmed cell death, caused by an enzyme caspases

Answer 13

Apoptosis

Question 14

chromatin is made of what

Answer 14

DNA wound around histones (proteins)

Question 15

DNA wound around the core of 8 histones is called what

Answer 15

Nucleosome

Question 16

6 characteristics of cancer cells

Answer 16

1. Lack differentiation
2. Abnormal nuclei
3. Do not undergo apoptosis
4. Form tumors
5. Undergo metastasis (tumor easily fragments to appear in other organs)
6. Undergo angiogenesis (form new blood vessels)

Question 17

prokaryotic cell division

Answer 17

Binary Fission
- produces two daughter cells identical to the parent cell (like mitosis)

Question 18

type of cell division used for sexual reproduction and its phases

Answer 18

Meiosis
- Two cycles: Meiosis I and Meiosis II (each contains Prophase, Metaphase, Anaphase, and Telophase)
- produces 4 genetically different daughter cells

Question 19

what is the “phase” between Meiosis I and Meiosis II?
- similar to interphase in Mitosis

Answer 19

Interkinesis

Question 20

what are the two ways meiosis brings about genetic diversity

Answer 20

Crossing-over and Independent assortment

Question 21

what is the haploid individual called in the life cycle

Answer 21

the gametophyte

Question 22

what is the diploid individual called in the life cycle

Answer 22

the sporophyte

Question 23

the production of sperm (spermatogenesis) produces how many?

Answer 23

produces 4 sperm cells

Question 24

the production of eggs (oogenesis) produces how many?

Answer 24

1 of the nuclei gets the majority of the cytoplasm and the 2-3 others wither away as polar bodies

Question 25

what is an individual's complete set of chromosomes called?

Answer 25

Karyotype

Question 26

what is a change in the chromosome number called? and what is it caused by?

Answer 26

It is called Aneuploidy and it is caused by nondisjunction

Question 27

what is trisomy and what is the most common type?

Answer 27

trisomy is when an individual has three of a particular type of chromosome - Trisomy 21 or Down Syndrome is the most common

Question 28

what is the syndrome where a female only has one X chromosome? (XO)

Answer 28

Turner Syndrome

Question 29

what is the syndrome where a male has an extra X chromosome? (XXY)

Answer 29

Klinefelter Syndrome

Question 30

what was Mendel's law that showed a pair of factors for one trait segregate independently of the factors for other traits - being green didn't make you tall and being yellow didn't make you short

Answer 30

the Law of Independent Assortment

Question 31

what can determine the genotype of an individual having the dominant phenotype

Answer 31

a Testcross

Question 32

what is an example of codominance

Answer 32

ABO blood type

Question 33

what is an example of incomplete dominance (heterozygote has a phenotype intermediate between that of either homozygote)

Answer 33

Familial Hypercholesterolemia (FH)

Question 34

what is an example of Pleiotropy (when a single mutant gene affects two or more distinct and seemingly unrelated traits

Answer 34

Marfan syndrome

Question 35

what are examples of Polygenic inheritance (when a trait is governed by two or more sets of alleles)

Answer 35

Skin color, height, and eye color

Question 36

two nucleotides with purine bases

Answer 36

Adenine (A) and Guanine (G)

Question 37

two nucleotides with pyrimidine bases

Answer 37

Thymine (T) and Cytosine (C)

Question 38

what stage of gene expression results in the formation of an mRNA molecule that carries the instructions for the specific protein

Answer 38

Transcription

Question 39

what stage of gene expression is the reading of the mRNA to make proteins, after mRNA is made from DNA

Answer 39

Translation

Question 40

what are the three stages of Transcription

Answer 40

1. Initiation - begins when RNA polymerase attaches to a region of DNA called the promoter 2. Elongation - RNA polymerase reads down the strand in the 3' to 5' direction and attaches the complementary RNA bases 3. Termination - RNA polymerase comes to a DNA stop sequence

Question 41

what does the cap on the 5' end do in transcription?

Answer 41

it is a modified guanine nucleotide that helps a ribosome determine where to attach when translation begins

Question 42

what does the Poly-A tail in transcription do?

Answer 42

it is 150-200 Adenines on the 3' end that facilitates the transport of mRNA out of the nucleus

Question 43

what stage of gene expression is the mRNA codon sequence turned into a protein (amino acid) sequence

Answer 43

Translation

Question 44

what are the three stages of translation - that occurs at ribosomes

Answer 44

1. Initiation - a small ribosomal subunit attaches to the mRNA transcript (always UAC anticodon and AUG start codon) 2. Elongation - the growth in length of the polypeptide 3. Termination - when tRNA moves to the E site and exits (same stages as transcription)

Question 45

what are the three binding sites that ribosomes have to facilitate pairing between tRNA and mRNA

Answer 45

E (for exit), P (for peptide) and A (for amino acid) site

Question 46

when has a gene been expressed?

Answer 46

when its product (a protein or RNA) is made and is operating in the cell

Question 47

Transcription is controlled by proteins called... - regulate by assisting the binding of RNA polymerase to the promoter

Answer 47

Transcription factors

Question 48

what does Posttranscriptional control of gene expression do

Answer 48

includes alternative mRNA splicing and controls the speed with which mRNA leaves the nucleus

Question 49

what does Translational control of gene expression do

Answer 49

determines to what degree mRNA is translated into a protein product once it reaches the cytoplasm

Question 50

what does Posttranslational control of gene expression do

Answer 50

affects the activity of a protein product (regulates activation and degradation rate) - last chance a cell has for influencing gene expression

Question 51

what is the microtubule-organizing center in animal cells

Answer 51

the Centrosome