BIOLOGY TEST 3 REVIEW Flashcards
A chromosome contains?
DNA and proteins
What are sister chromatids?
Sister chromatids are are two strands of genetically identical chromosomes
What are chromosomes?
carries genetic information in the form of genes: made up of nucleic acids and proteins
How many chromosomes do humans have?
46
What is the diploid number? What has it?
The diploid (2n) number includes two sets of chromosomes of each type. The diploid number is found in all the non-sex cells of an organism’s body (with a few exceptions).
What is the haploid number? What has it?
he haploid (n) number contains one of each kind of chromosome. In the life cycle of many animals, only sperm and egg cells have the haploid number
What is binary fission?
Binary fission of prokaryotic cells produces two genetically identical daughter cells.
In binary fission, what happens before cell division?
DNA is replicated—both chromosomes are attached to a special site inside the plasma membrane.
In binary fission, what happens after DNA is replicated and the chromosomes have been attached to a special site inside the plasma membrane?
The two chromosomes separate as a cell lengthens and pulls them apart.
In binary fission, what happens after the two chromosomes separate as a cell lengthens and pulls them apart?
A new plasma membrane and cell wall develop and grow inward to divide the cell. When the cell is approximately twice its original length, the new cell wall and plasma membrane for the two daughter cells are complete.
Describe the chromosomes of bacteria. How are they different than eukaryotic chromosomes? What do they look like?
composed of DNA and associated proteins, but much less protein than eukaryotic chromosomes. The chromosome appears as a nucleoid (an irregular-shaped region that is not enclosed by a membrane) The chromosome is a circular loop attached to the inside of the plasma membrane; it is about 1,000 times the length of the cell
What are stages of the cell cycle?
Interphase (G1, S, G2) Prophase, Pro-metaphase, Metaphase, Anaphase, Telophase, Cytokinesis
What happens in the G1 stage? What is it prior to? What happens to the cell/organelles?
just prior to DNA replication; a cell grows in size, organelles increase in number, and material accumulates for DNA synthesis.
What happens in the S stage? What is synthesized? What happens to chromosomes?
The S stage is the DNA synthesis (replication) period; proteins associated with DNA are also synthesized;
at the end of the S stage, each chromosome has two identical DNA double helix molecules, called sister
chromatids.
What happens in the G2 stage? What is it prior to? What is synthesized
The G2 stage occurs just prior to cell division; the cell synthesizes proteins needed for cell division, such as proteins in microtubules.
What is mitosis?
nuclear division. daughter chromosomes are distributed by the mitotic spindle to two daughter nuclei.
What happens in prophase of mitosis?
a. Nuclear division is about to occur: (blank) condenses and (blank) become visible.
b. The (blank) disappears and the (blank) fragments.
c. Duplicated chromosomes are composed of (blank) sister chromatids held together by a (blank);chromosomes have no particular orientation in the cell at this time.
d. The (blank) begins to assemble as pairs of (blank) migrate away from each other.
e. An array of microtubules called (blank) radiates toward the (blank) from the centrosomes.
a. Nuclear division is about to occur: chromatin condenses and chromosomes become visible.
b. The nucleolus disappears and the nuclear envelope fragments.
c. Duplicated chromosomes are composed of two sister chromatids held together by a centromere;
chromosomes have no particular orientation in the cell at this time.
d. The spindle begins to assemble as pairs of centrosomes migrate away from each other.
e. An array of microtubules called asters radiates toward the plasma membrane from the centrosomes.
What happens in pro-metaphase of mitosis? ‘
a. Specialized protein complexes called (blank) develop on each side of the (blank) for future chromosome orientation.
b. An important event during prometaphase is attachment of the chromosomes to the (blank)
c. The kinetochores attach (blank) to the kinetochore (blank)
a. Specialized protein complexes (kinetochores) develop on each side of the centromere for future
chromosome orientation.
b. An important event during prometaphase is attachment of the chromosomes to the spindle.
c. The kinetochores attach sister chromatids to the kinetochore spindle fibers.
What happens in metaphase of mitosis?
a. (blank), attached to kinetochore fibers, are now in alignment at the metaphase (blank), an imaginary plane that indicates the future axis of cell division.
b. Non-attached spindle fibers, called (blank) spindle fibers, can reach beyond the metaphase plate and overlap.
c. A cell checkpoint called the (blank) checkpoint delays the start of anaphase until kinetochores are properly
attached to the spindle fibers, and chromosomes are properly aligned along the metaphase plate.
a. Chromosomes, attached to kinetochore fibers, are now in alignment at the metaphase plate, an imaginary plane that indicates the future axis of cell division.
b. Non-attached spindle fibers, called polar spindle fibers, can reach beyond the metaphase plate and overlap.
c. A cell checkpoint called the M checkpoint delays the start of anaphase until kinetochores are properly
attached to the spindle fibers, and chromosomes are properly aligned along the metaphase plate.
What happens in anaphase of mitosis?
a. The two (blank) of each duplicated chromosome separate at the centromere.
b. (blank) chromosomes, each with a centromere and single chromatid, move toward opposite poles.
i. (blank) spindle fibers lengthen as they slide past each other.
ii. (blank) spindle fibers disassemble at the kinetochores; this pulls daughter chromosomes to
poles.
iii. The motor molecules (blank) and (blank) are involved in this sliding process.
iv. Anaphase is the (blank) stage of mitosis.
a. The two sister chromatids of each duplicated chromosome separate at the centromere.
b. Daughter chromosomes, each with a centromere and single chromatid, move toward opposite poles.
i. Polar spindle fibers lengthen as they slide past each other.
ii. Kinetochore spindle fibers disassemble at the kinetochores; this pulls daughter chromosomes to
poles.
iii. The motor molecules kinesin and dynein are involved in this sliding process.
iv. Anaphase is the shortest stage of mitosis.
What happens in telophase of mitosis?
a. The (blank) disappears in this stage.
b. The (blank) reforms around the daughter chromosomes.
c. The daughter chromosomes diffuse, again forming (blank).
d. The (blank) reappears in each daughter nucleus.
a. The spindle disappears in this stage.
b. The nuclear envelope reforms around the daughter chromosomes.
c. The daughter chromosomes diffuse, again forming chromatin.
d. The nucleolus reappears in each daughter nucleus.
What is cytokinesis?
division of the cytoplasm
What happens in cytokinesis in animals?
a. A (blank) indents the plasma membrane between the two daughter nuclei at a midpoint; this deepens to divide the (blank)during cell division.
b. Cytoplasmic cleavage begins as (blank) draws to a close and organelles are distributed.
c. The (blank) deepens as a band of actin filaments, called the (blank), constricts between the two daughter cells.
d. A narrow bridge exists between daughter cells during (blank) until constriction completely separates the cytoplasm.
a. A cleavage furrow indents the plasma membrane between the two daughter nuclei at a midpoint; this deepens to divide the cytoplasm during cell division.
b. Cytoplasmic cleavage begins as anaphase draws to a close and organelles are distributed.
c. The cleavage furrow deepens as a band of actin filaments, called the contractile ring, constricts
between the two daughter cells.
d. A narrow bridge exists between daughter cells during telophase until constriction completely separates the cytoplasm.
What happens in cytokinesis in plants?
a. The rigid (blank) that surrounds plant cells does not permit cytokinesis by furrowing.
b. The Golgi apparatus produces vesicles, which move along the (blank) to a small flattened disc that has formed.
c. (blank) fuse forming a cell plate; their membranes complete the plasma membranes of the daughter cells.
d. The new membrane also releases (blank) from the new plant cell walls; the cell walls are strengthened by the addition of (blank)
a. The rigid cell wall that surrounds plant cells does not permit cytokinesis by furrowing.
b. The Golgi apparatus produces vesicles, which move along the microtubules to a small flattened disc that has formed.
c. Vesicles fuse forming a cell plate; their membranes complete the plasma membranes of the daughter cells.
d. The new membrane also releases molecules from the new plant cell walls; the cell walls are strengthened by the addition of cellulose fibrils.
What are spindle fibers
Just outside the nucleus is the centrosome. (in animals it contains centrioles)
Centrosome organizes the mitotic spindle. The spindle contains many fibers. Each fiber is composed of a cylindrical bundle of microtubules. Microtubules assemble when tubulin subunits join and when the subunits disassemble they form mitotic spindle fibers
How many chromosomes are in each cell after mitosis and cytokinesis?
46
What is the centromere?
a region of constriction on a chromosome. Holds together sister chromatids of a chromosome
What is meiosis? What does it do to the number of chromosomes? What does it involve?
nuclear division, reducing the chromosome number from the diploid (2n) to the haploid (n)number. Meiosis involves two nuclear divisions and produces four haploid daughter cells. Each daughter cell has half the number of chromosomes found in the diploid parent nucleus.
What happens in Meiosis I? What happens prior to it? How many chromatids? What is formed? What process occurs?
Prior to meiosis I, DNA replication occurs, each chromosome thus has two sister chromatids. b. During meiosis I, homologous chromosomes pair forming a synaptonemal complex; this process is called synapsis. During synapsis, the two sets of paired chromosomes lay alongside each other as a bivalent (sometimes called a tetrad).
What happens in Prophase I?
1. (blank) is about to occur: (blank) disappears; (blank) fragments; (blank) migrate away from each other; and (blank) assemble.
2. (blank) chromosomes undergo (blank) to form bivalents; (blank) may occur at this time in
which case sister chromatids are no longer identical.
3. (blank) condenses and (blank) become microscopically visible.
- Nuclear division is about to occur: nucleolus disappears; nuclear envelope fragments; centrosomes
migrate away from each other; and spindle fibers assemble. - Homologous chromosomes undergo synapsis to form bivalents; crossing-over may occur at this time in
which case sister chromatids are no longer identical. - Chromatin condenses and chromosomes become microscopically visible.
What happens in metaphase I?
1. Bivalents held together by (blank) have moved toward the metaphase plate at the equator of the spindle.
2. In metaphase I, there is a fully formed (blank) and alignment of the (blank) the metaphase plate.
3. Kinetochores, protein complexes just outside the centromeres, attach to spindle fibers called (blank)
spindle fibers.
4. Bivalents independently align themselves at the metaphase (blank) of the spindle.
5. Maternal and paternal (blank) of each bivalent may be oriented toward either pole.
- Bivalents held together by chiasmata have moved toward the metaphase plate at the equator of the
spindle. - In metaphase I, there is a fully formed spindle and alignment of the bivalents at the metaphase plate.
- Kinetochores, protein complexes just outside the centromeres attach to spindle fibers called kinetochore
spindle fibers. - Bivalents independently align themselves at the metaphase plate of the spindle.
- Maternal and paternal homologues of each bivalent may be oriented toward either pole.
What happens in Anaphase I?
- The (blank) of each bivalent separate and move toward opposite poles.
- Each chromosome still has two (blank)
- The homologues of each bivalent separate and move toward opposite poles.
- Each chromosome still has two chromatids.
What happens in Telophase I?
- In (blank), this stage occurs at the end of meiosis I.
- When it occurs, the (blank) reforms and (blank) reappear.
- This phase may or may not be accompanied by (blank)
- In animals, this stage occurs at the end of meiosis I.
- When it occurs, the nuclear envelope reforms and nucleoli reappear.
- This phase may or may not be accompanied by cytokinesis
What is interkinesis?
Interkinesis between meiosis I and II is similar to the interphase between mitotic divisions; however, no DNA replication occurs (the chromosomes are already duplicated).
What happens in Meiosis II?
In meiosis II, the (blank) divide and (blank) (derived as sister chromatids) separate. No replication of (blank) is needed between meiosis I and II because chromosomes are already doubled (DNA replication occurred prior to meiosis I). b. Chromosomes in the four daughter cells have only one (blank). c. Counting the number of centromeres verifies that parent cells were (blank); each daughter cell is (blank). d. In the animal life cycle, daughter cells become (blank) that fuse during fertilization. (blank) restores the diploid number in cells.
In meiosis II, the centromeres divide and daughter chromosomes (derived as sister chromatids) separate. a. No replication of DNA is needed between meiosis I and II because chromosomes are already doubled (DNA replication occurred prior to meiosis I). b. Chromosomes in the four daughter cells have only one chromatid. c. Counting the number of centromeres verifies that parent cells were diploid; each daughter cell is haploid. d. In the animal life cycle, daughter cells become gametes that fuse during fertilization. .Fertilization restores the diploid number in cells.
During metaphase II, the (blank) number of chromosomes align at the metaphase plate.
haploid
During anaphase II, the (blank) separate at the centromeres; the two (blank) move toward the poles.
sister chromatids; daughter chromosomes
In Meiosis II, Due to crossing-over, each (blank) can contain chromosomes with different types of genes.
gamete
At the end of telophase II and cytokinesis, there are four (blank) cells.
In animals, the haploid cells mature and develop into (blank)
In plants, the daughter cells become (blank) and divide to produce a haploid generation; these haploid
cells fuse to become a (blank) that develops into a diploid generation.
haploid
gametes
spores
zygote
What is the alternation of generations?
The type of life cycle of alternating haploid and diploid generations
What is crossing-over? What does it introduce?
an exchange of genetic material between non-sister chromatids of a bivalent; this introduces variation.
At synapsis, homologous chromosomes are held in position by a nucleoprotein lattice called (blank) The lattice holds the (blank) together so that the DNA of the duplicated chromosomes of each homologue pair is aligned, then (blank) may occur.
As the lattice of the synaptonemal complex breaks down, homologues are temporarily held together by (blank) regions where the (blank) chromatids are attached due to DNA strand exchange and crossing-over
The (blank) separate and are distributed to daughter cells.
Due to this genetic (blank), daughter chromosomes derived from sister chromatids are no longer identical.
(the synaptonemal complex). bivalents; crossing-over
chiasmata, non-sister, homologues, recombination
In males, meiosis is part of (blank) (the production of sperm), and occurs in the (blank)
spermatogenesis; testes
In females, meiosis is part of (blank) (the production of eggs), and occurs in the (blank)
oogenesis; ovaries
- Spermatogenesis
a. In the testes of males, primary (blank) with (blank) chromosomes undergo meiosis I to form two secondary (blank) , each with (blank) duplicated chromosomes.
b. Secondary (blank) divide (meiosis II) to produce four (blank), also with (blank) daughter
chromosomes.
c. Spermatids then differentiate into (blank) (spermatozoa).
d. Meiotic cell division in males always results in (blank) cells that become sperm.
Immature sperm is? Mature sperm is?
a. spermatocytes; 46; spermatocytes; 23
b. spermatocytes; spermatids; 23
c. sperm
d. four
spermatocyte; spermatid
- Oogenesis
a. In the ovaries of human females, primary (blank) with (blank) chromosomes undergo meiosis I to form
two cells, each with (blank) duplicated chromosomes.
b. One of the cells, a secondary (blank) receives almost all the cytoplasm; the other cell, (blank), disintegrates or divides again.
c. The secondary (blank) begins meiosis II and then stops at metaphase II.
d. At (blank), the secondary (blank) leaves the ovary and enters an (blank) where it may meet a
sper
e. If a (blank) enters the secondary (blank), it is activated to continue meiosis II to completion;
the result is a (blank) and another (blank), each with (blank) daughter chromosomes.
f. Meiosis produces one (blank) and three (blank); (blank) serve to discard unnecessary chromosomes and retain most of the cytoplasm in the egg.
g. The cytoplasm serves as a source of nutrients for the developing (blank)
a. oocytes; 46; 23
b. oocyte; a polar body
c. oocyte;
d. ovulation; oocyte; oviduct
e. sperm; oocyte; mature egg; polar body; 23
f. egg; polar bodies; polar bodies
g. embryo
In plants, there are two adult stages: one is diploid (called the (blank)) and one is haploid (called the (blank)).
sporophyte; gametophyte
What did Gregor Mendel do?
he was an Australian monk who formulated two fundamental laws of heredity in the early 1860s. Mendel’s particulate theory is based on the existence of minute particles—now called genes.
What did Gregor Mendel do with garden peas? Why did he choose them?
b. From many varieties, Mendel chose 22 (blank) varieties for his experiments.
c. (blank) varieties had all offspring like the parents and like each other.
d. Mendel studied simple (blank) e.g., seed shape and color, flower color, etc.).
2. He used his understanding of (blank) to interpret his results.
He chose the garden pea, Pisum sativum, because peas were easy to cultivate, had a short generation time, and could be cross-pollinated by hand.
b. From many varieties, Mendel chose 22 true-breeding varieties for his experiments.
c. True-breeding varieties had all offspring like the parents and like each other.
d. Mendel studied simple traits (e.g., seed shape and color, flower color, etc.).
2. He used his understanding of mathematical principles of probability to interpret his results.
How did Gregor Mendel cross-pollinate?
He performed reciprocal crosses, i.e., pollen of tall plant to stigma of short plant and vice versa. cross-pollinated by hand. Pollen was transferred from the male (anther) of one plant to the female (stigma) parts of another plant. Cut away anthers and brushed on pollen from another plant.
Mendel confirmed that his tall plants always had tall offspring, i.e., were true-breeding, before what
before crossing two different strains that differed in only one trait
Mendel tracked each trait through two generations.
a. P generation is the (blank) generation in a breeding experiment.
b. F 1 generation is the (blank) offspring in a breeding experiment.
c. F 2 generation is the (blank) offspring in a breeding experiment
parental
first generation
second generation
Characteristics of other parents reappeared in about 1/4 of F 2 plants; 3/4 of offspring resembled the F 1 plants.
Mendel saw that these 3:1 results were possible if:
factors separated when gametes were formed; a gamete carried one copy of each factor and random fusion of all possible gametes occurred upon fertilization.
What does homozygous mean?
two identical alleles for a trait. Homozygous dominant genotypes possess two dominant alleles for a trait. Homozygous recessive genotypes possess two recessive alleles for a trait.
What does heterozygous mean?
possess one of each allele for a particular trait.
What is a phenotype?
Phenotype refers to the physical appearance of the individual (tall, short, etc.).
What is a genotype?
Genotype refers to the alleles an individual receives at fertilization (dominant, recessive).
What is a monohybrid cross?
A monohybrid cross is between two parent organisms true-breeding for two distinct forms of one trait.
What is a dihybrid cross?
A dihybrid cross is between two parent organisms that are true-breeding for different forms of two traits; it produces offspring heterozygous for both traits.
What is the law of segregation?
a. Each organism contains (blank) factors for each (blank)
b. (blank) segregate during the formation of (blank)
c. Each (blank) contains one (blank) for each trait.
d. (blank) gives each new individual two (blank) for each trait.
a. Each organism contains two factors for each trait.
b. Factors segregate during the formation of gametes.
c. Each gamete contains one factor for each trait.
d. Fertilization gives each new individual two factors for each trait.
What is DNA? What is it made up of?
Deoxyribonucleic acid. DNA is a double helix. DNA is made up of sugar-phosphate backbones with nucleotides that contain a nitrogenous base, a (sugar) phosphate, and a pentose
What are the functions of DNA?
stores genetic information
stable and able to be replicated accurately during cell division and transmitted from generation to generation
able to undergo mutations to provide genetic variability
What are DNA’s nucleotides?
adenine, thymine, guanine, cytosine
Nucleotides (blank) and (blank) are purine
Nucleotides (blank) and (blank) are pyrimidine
adenine (A) and guanine (G)
thymine (T) and cytosine (C)
What is a purine?
a type of nitrogen-containing base having a double-ring structure.
What is a pyrimidine?
a type of nitrogen- containing base having a single-ring structure.
What did Watson and Crick do?
double helix!!! Using information generated by Chargaff and Franklin, Watson and Crick constructed a model of DNA as a double helix with sugar-phosphate groups on the outside, and paired bases on the inside
What did Rosalind Franklin do? What did it show?
produced X-ray diffraction photographs Franklin’s work provided evidence that DNA had the following features:
a. DNA is a helix.
b. Some portion of the helix is repeated
What are Chargaff’s rules?
a. The amount of A, T, G, and C in DNA varies from species to species.
b. In each species, the amount of A = T and the amount of G = C.
:Information stored in DNA must be read in the (blank) direction so DNA is replicated in a (blank) direction.
5’ to 3’; 5’ to 3’
In DNA replication, each strand of the original double helix in a (blank) molecule serves as a template for a new strand in a (blank) molecule
parent; daughter
What happens in DNA replication?
Unwinding, Complementary base pairing, and joining
What happens in unwinding?
old strands of the (blank) DNA molecule are unwound as weak (blank) bonds between the paired bases are “unzipped” and broken by the enzyme (blank)
old strands of the parent DNA molecule are unwound as weak hydrogen bonds between the paired bases are “unzipped” and broken by the enzyme helicase.
What happens in complementary base pairing?
free (blank) present in the nucleus bind with (blank) on unzipped portions of the two strands of DNA; this process is catalyzed by (blank)
free nucleotides present in the nucleus bind with complementary bases on unzipped portions of the two strands of DNA; this process is catalyzed by DNA polymerase.
What happens in joining?
complementary (blank) bond to each other to form new strands; each (blank) DNA molecule contains an old strand and a new strand; this process is also catalyzed by (blank)
complementary nucleotides bond to each other to form new strands; each daughter DNA molecule contains an old strand and a new strand; this process is also catalyzed by DNA polymerase.
What are RNA’s nucleotides? What is replaced from DNA?
uracil (U), adenine (A), cytosine (C), and guanine (G).
Uracil (U) replaces thymine (T) of DNA.
How many codons are there?
64
How many amino acids are there?
20
What is transcription?
the first step in gene expression; it is the process whereby a DNA strand serves as a template for the formation of mRNA.
What is translation?
an mRNA transcript directs the sequence of amino acids in a polypeptide.
In Transcription, A segment of the DNA helix…
unwinds and unzips.
Transcription begins when (blank) attaches to a (blank) on DNA
RNA polymerase; promoter
What is a promoter? It defines what?
a region of DNA which defines the start of the gene, the direction of transcription, and the strand to be transcribed.
What is RNA polymerase?
an enzyme that speeds formation of RNA from a DNA template
Transcription: As (bank) moves along the
template strand of the DNA, complementary RNA (blank) are paired with DNA (blank) of the (blank) strand. The strand of DNA not being transcribed is called the (blank) strand.
RNA polymerase; nucleotides; nucleotides; coding; noncoding
Transcription: RNA polymerase adds (blank) to the (blank) end of the polymer under construction. Thus, RNA synthesis is in the (blank) direction.
nucleotides; 3’ ; 5’-to-3’
Transcription: The RNA/DNA association is not as stable as the DNA double helix; therefore, only the newest portion of the (blank) molecule associated with (blank) is bound to DNA; the rest dangles off to the side.
RNA; RNA polymerase
Transcription: Elongation of (blank) continues until (blank) comes to a stop sequence.
mRNA; RNA polymerase
Transcription: The stop sequence causes RNA polymerase to stop transcribing (blank) and to release the (blank) transcript.
DNA; mRNA
Transcription: Many RNA polymerase molecules work to produce (blank) from the same (blank) region at the same time.
mRNA; DNA
Transcription: Cells produce thousands of copies of the same (blank) molecule and many copies of the same (blank) in a shorter period of time than if a single copy of (blank) were used to direct protein synthesis.
mRNA; protein; RNA
Transcription: mRNA production: newly formed pre-mRNA transcript is processed before leaving the (blank)
nucleus
Transcription: Pre-mRNA transcript is the immediate product of (blank); it contains (blank) and (blank)
transcription; exons and introns.
Transcription: The ends of the (blank) molecule are altered: a (Blank) is put on the 5’; end and a (blank) is put on the 3’ end.
mRNA; cap; poly-A tail
Transcription: The (blank) is a modified (blank) where a ribosome attaches to begin translation
cap; guanine (G)
Transcription: The (blank) consists of a 150–200 (blank)nucleotide chain that facilitates transport of mRNA out of the nucleus and inhibits enzymatic degradation of mRNA.
poly-A tail; adenine (A)
Transcription: An (blank) is a protein-coding region of the DNA code in the pre-mRNA transcript eventually expressed in the final polypeptide product.
exon
Transcription: An (blank) is a non-protein coding region of DNA removed by “self-splicing” or spliceosomes before the mRNA leaves the nucleus.
intron
Transcription: (blank) are enzymes made of RNA with the function of removing introns from.
Ribozymes
Transcription: RNA could have served as both (blank) and as the first (blank) in early life forms.
genetic material; enzymes
Transcription: (blank) contain smaller nuclear RNAs (blank). (blank) cut the pre-mRNA transcript and then rejoin adjacent exons. (blank) are capable of identifying the introns to be removed.
Spliceosomes; snRNAs
Transcription: (blank) give a cell the ability to decide which exons will go in a particular mRNA.
Introns
Transcription: mRNA do not have all of the possible (blank) available from a DNA sequence. What is an (blank) in one mRNA could be an (blank) in another mRNA. This process is termed (blank)
exons; exon; intron; alternative mRNA splicing.
Some introns give rise to (blank) which regulate mRNA translation by bonding with mRNA through (blank) and preventing (blank) from occurring.
microRNAs (miRNA); complementary base pairing; translation
(blank) shuffling occurs when introns encourage crossing over during (blank)
Exon; meiosis
(blank) takes place in the cytoplasm of eukaryotic cells. It is the second step by which gene expression leads to protein synthesis.
Translation
In Translation, One language (blank) is translated into another language (blank).
nucleic acids; protein
What happens in the three steps of translation?
- During translation, (blank) codons base-pair with (blank) anticodons carrying specific amino acids.
- Codon order determines the order of tRNA molecules and the sequence of (blank) in polypeptides.
- Protein synthesis involves (blank), (blank), and (blank)
- (blank) are required for all three steps; (blank) is needed for the first two steps.
- During translation, mRNA codons base-pair with tRNA anticodons carrying specific amino acids.
- Codon order determines the order of tRNA molecules and the sequence of amino acids in
polypeptides. - Protein synthesis involves initiation, elongation, and termination.
- Enzymes are required for all three steps; energy (ATP) is needed for the first two steps.
What happens in the initiation of translation?
a. A small ribosomal subunit attaches to (blank) in the vicinity of the start codon (blank).
b. The first or initiator (blank) pairs with this codon; then the large ribosomal subunit joins to the small subunit.
c. Each ribosome contains three binding sites: the P (blank) site, the A (blank) site, and the E (blank) site.
d. The initiator (blank) binds to the (blank) site although it carries one amino acid, methionine.
e. The (blank) site is for the next tRNA carrying the next amino acid.
f. The (blank) site is to discharge (blank) from the ribosome.
g. Initiation factor (blank) are required to bring together the necessary translation components: (4 blanks)
a. A small ribosomal subunit attaches to mRNA in the vicinity of the start codon (AUG).
b. The first or initiator tRNA pairs with this codon; then the large ribosomal subunit joins to the
small subunit.
c. Each ribosome contains three binding sites: the P (for peptide) site, the A (for amino acid) site, and the E (for exit) site.
d. The initiator tRNA binds to the P site although it carries one amino acid, methionine.
e. The A site is for the next tRNA carrying the next amino acid.
f. The E site is to discharge tRNAs from the ribosome.
g. Initiation factor proteins are required to bring together the necessary translation components: the small ribosomal subunit, mRNA, initiator tRNA, and the large ribosomal subunit.
What happens in the elongation part of translation?
a. The tRNA with attached polypeptide is at the P site; a (blank) complex arrives at the A site.
b. Proteins called (blank) factors facilitate complementary base pairing between the tRNA anticodon and the mRNA codon.
c. The polypeptide is transferred and attached by a (blank) bond to the newly arrived amino acid in the A site.
d. This reaction is catalyzed by a (blank) which is part of the larger subunit.
e. The (blank) molecule in the P site is now empty.
f. (blank) occurs with mRNA, along with peptide-bearing tRNA, moving to the P site and the spent tRNA moves from the P site to the E site and exits the ribosome.
g. As the ribosome moves forward three nucleotides, there is a new(blank)now located at the empty A site.
h. The complete cycle is rapidly repeated, about 15 times per second in Escherichia coli.
i. The ribosomes will reach a stop codon, termination will occur, and the (blank) will be released.
a. The tRNA with attached polypeptide is at the P site; a tRNA-amino acid complex arrives at the A site.
b. Proteins called elongation factors facilitate complementary base pairing between the tRNA
anticodon and the mRNA codon.
c. The polypeptide is transferred and attached by a peptide bond to the newly arrived amino acid in
the A site.
d. This reaction is catalyzed by a ribozyme, which is part of the larger subunit.
e. The tRNA molecule in the P site is now empty.
f. Translocation occurs with mRNA, along with peptide-bearing tRNA, moving to the P site and the
spent tRNA moves from the P site to the E site and exits the ribosome.
g. As the ribosome moves forward three nucleotides, there is a new codon now located at the empty A site.
h. The complete cycle is rapidly repeated, about 15 times per second in Escherichia coli.
i. The ribosomes will reach a stop codon, termination will occur, and the peptide will be released.
What happens in the termination part of translation?
a. Termination of (blank) synthesis occurs at a stop codon that does not code for an (blank)
b. The polypeptide is enzymatically (blank) from the last (blank) by a release factor.
c. The (blank) and (blank) leave the ribosome, which dissociates into its two subunits.
a. Termination of polypeptide synthesis occurs at a stop codon that does not code for an amino acid.
b. The polypeptide is enzymatically cleaved from the last tRNA by a release factor.
c. The tRNA and polypeptide leave the ribosome, which dissociates into its two subunits.
Transfer RNA (tRNA) molecules transfer (blank) to the (blank)
amino acids; ribosomes
The tRNA is a single-stranded ribonucleic acid that doubles back on itself to create regions where
(blank) are (blank)-bonded to one another.
complementary bases; hydrogen
Translation (tRNA): The (blank) binds to the 3’ end; the opposite end of the molecule contains a(n) (blank) that binds to the (blank) codon in a complementary fashion.
amino acid; anticodon; mRNA
Translation (tRNA): There is at least one (blank) molecule for each of the 20 amino acids found in proteins.
tRNA
Translation (tRNA): There are fewer (blank) than codons because some (blank) pair with more than one codon; if an anticodon contains a (blank) in the third position, it will pair with either an A or G—this is called the (blank)
tRNAs; U; wobble hypothesis
Translation (tRNA): (blank) are amino acid-charging enzymes that recognize which amino acid should join which tRNA molecule, and covalently joins them. This requires ATP.
Aminoacyl-tRNA synthetases
Translation (tRNA): An (blank) forms, which then travels to a ribosome to “transfer” its amino acid during protein synthesis.
amino acid–tRNA complex
Translation (rRNA): Ribosomal RNA (rRNA) is produced from a (blank) template in the (blank) of the nucleus
Ribosomal RNA (rRNA); nucleolus
Translation (rRNA): The rRNA is packaged with a variety of (blank) into (blank) subunits, one larger than the other.
protein; ribosomal subunits
Translation (rRNA): Subunits move separately through (blank) pores into the cytoplasm where they combine when (blank) begins.
nuclear envelope; translation
Translation (rRNA): Ribosomes can remain in the (blank) or attach to the (blank)
cytoplasm; endoplasmic reticulum
What cell contains more ribosomes? prokaryotic or eukaryotic
eukaryotic
Ribosomes have a binding site for (blank) and binding sites for two (blank) molecules.
mRNA; tRNA
Ribosomes facilitate complementary base pairing between (blank) anticodons and (blank) codons; (blank) acts as an enzyme (blank)) that joins amino acids together by means of a (blank) bond.
tRNA; mRNA; rRNA; ribozyme; peptide
in translation, A ribosome moves down the (BLANK) molecule, new (blank) arrive, the (blank) join, and a (blank) forms.
mRNA; tRNA; amino acids; polypeptide
Translation terminates once the (blank) is formed; the (blank) then dissociates into its two subunits.
polypeptide; ribosome
(blank) are clusters of several ribosomes synthesizing the same protein.
Polyribosomes
To get from a polypeptide to a functioning protein requires correct bending and twisting; (blank) molecules assure that the final protein develops the correct shape.
chaperone
How many chromosomes do sperm and egg cells have? Are they haploid or diploid?
23; HAPLOID!!!!!!
G1 Checkpoint?
checks for DNA damage
G2 Checkpoint?
checks if DNA replicated properly
M Checkpoint?
Checks if chromosomes are aligned during metaphase
Cells that do not divide are in what phase?
G0 phase
Apoptosis?
programmed cell death; Apoptosis is caused by enzymes called caspases.
What is p53?
stops cell cycle at G1 if cell’s DNA is damaged
Abnormal growth of cells is called a
tumor
(blank) tumors are not cancerous. Encapsulated. Do not invade neighboring tissue or spread
Benign tumors are not cancerous.
Encapsulated
Do not invade neighboring tissue or spread
(blank) tumors are cancerous. Not encapsulated. Readily invade neighboring tissues. May also detach and lodge in distant places (metastasis) Results from mutation of genes regulating the cell cycle
Malignant
Characteristics of Cancer Cells?
Lack differentiation, Have abnormal nuclei, Do not undergo apoptosis, Undergo metastasis, Form tumors
Undergo angiogenesis
They form new blood vessels.
Mutations in telomerase gene:
Cause telomeres to continue to lengthen, which
Allows cancer cells to continually divide
law of independent assortment?
Pair of factors for one trait segregate independently of the factors for other traits
(blank) in genes specify information, but information is not structure and function.
Genetic information is expressed into structure and function through (blank) .
DNA; protein synthesis
DNA in a gene determines the sequence of (blank) in an (blank) molecule.
RNA controls the primary structure of a (BLANK)
nucleotides; RNA; protein
