Exam 3 Flashcards
1
Q
What is the genetic blueprint of the cell?
A
Deoxyribonucleic acid (DNA)
2
Q
Where can DNA be found in the cell?
A
Nucleus & Mitochondria
3
Q
A substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together
A
Polymer
4
Q
What kinds of bonds do the bases share?
A
Hydrogen bonds (easy to break & put together)
5
Q
What kind of bonds does the backbone of DNA share?
A
Covalent bonds (strong)
6
Q
What is DNA composed of?
A
Adenine
Guanine
Thymine
Cytosine
7
Q
What are the purines?
A
Adenine & Guanine (two rings)
8
Q
What are the pyrimidines?
A
Thymine & Cytosine (also Uracil)
9
Q
What base pairs bond to which?
A
A-T
C-G
10
Q
DNA strands are complementary, meaning:
A
If you see one strand, you can predict what the other strand looks like
11
Q
What is a gene?
A
A unit of heredity
12
Q
What is a genome?
A
The complete DNA sequence for a particular organism or individual in a cell
13
Q
Approximately how many genes do we posses?
A
20,000 = 100,000 proteins
14
Q
The information encoded in a gene is transcribed and then translated into a protein
A
Gene expression (Cells use 5% of blueprint)
15
Q
What is the link between DNA and protein?
A
Ribonucleic acid (RNA)
16
Q
What is the central dogma of molecular biology?
A
DNA is TRANSCRIBED to RNA which is then TRANSLATED into PROTEINS
17
Q
What is the cell theory?
A
All cells come from other cells
They reproduce by division
18
Q
What is DNA replication?
A
Unzipping the double helix, then using each strand to synthesize complementary strand
19
Q
How is DNA organized in nucleus?
A
It is wrapped around proteins called histones that then form chromatin
20
Q
DNA-histone complex=
A
Chromatin
21
Q
Chromatin is packaged into what?
A
46 chromosomes
22
Q
Chromosomes exist in:
A
Pairs
23
Q
Chromosome pairs contain the same genes
A
Homologous
24
Q
What kind of cells are used in mitosis?
A
Somatic cells
25
What chromosome is the gene blood codes for?
Chromosome 9 (ABO)
26
In a cell that is not dividing (undividing) what is in the nucleus?
Chromatin
27
What is the first step of cell division?
DNA duplication
28
After DNA duplication, what is formed?
1 chromosome = 2 sister chromatids
29
What is the part on a chromosome where two sister chromatids are attached?
Centromere
30
The life cycle of a cell from cell division to cell division is known as:
Cell Cycle
31
DNA duplication occurs in what phase?
S phase
32
What happens in the G2 phase?
Normal cell functions in preparation for mitosis
33
The splitting of sister chromatids of the duplicated DNA & their relocation to different areas of the cell
Mitosis
34
What are the transport "rails" of the cell?
Microtubles
35
Organelles where microtubles are synthesized and organized
Centrosomes
36
The second centrosome is made in what phase?
G2 Phase
37
What happens in prophase of mitosis?
DNA condensed into chromosomes
Nuclear membrane disintegrates
Centrosome copies move to the "poles" & synthesize microtubles
Chromosomes begin to line up along equatorial plane of cell
38
What happens in transisition to metaphase (Prometaphase)?
Spindle forms
| Spindle microtubles become attached to the sister chromatids of each chromosome (kinetochore)
39
What happens in metaphase?
Nuclear membrane has completely disintegrated
Microtubles attach to sister chromatids of each chromosome
Microtubles have formed mitotic spindle (cage like structure)
Chromosomes line up at the spindle midline or equator (metaphase plate)
40
What happens in anaphase?
Sister chromatids are pulled apart by the mitotic spindle (motor proteins & degradative enzymes)
Once separated, each former sister chromatid is referred to as a daughter chromosome
Cell elongates***
41
What happens in telophase?
Chromosomes de-condense
Nuclear membrane reforms
Microtubules begin to disintgrate
Two sets of protein filaments form at equatorial plane
42
What is cytokinesis?
Protein microfilaments form contractive rings
43
What are filaments and microtubules main functions?
Filaments mediate cytokinesis
| Microtubles mediate mitosis
44
How do plant cells differ?
Instead of cytokinesis they do a cell plate formation
45
Mitotic cell division=
Mitosis
46
Sexually reproducing organisms. Chromosomes always come in homologous pairs, one set inherited from their mother, one set from their father
Diploid (2N)
47
Asexually reproducing organisms. Only one set of chromosomes inherited from the parent
Haploid (N)
48
Sperm & egg cells are haploid until...
Formed together to form a zygote (diploid)
49
How many cell divisions are in Meiosis?
2
50
Where does Mitosis and Meiosis show a physical difference?
Metaphase
51
What can take place in Prophase I of Meiosis?
Crossover (increasing genetic diversity)
52
What does the two homologous pairs form when paired right next to each other?
Tetrad
53
The random alignment that takes place on the metaphase plate in Metaphase I during Meiosis is called:
Independent assortment
54
After completion of Meiosis I/cytokinesis, each human cell going through the process contains:
23 chromosomes/46 sister chromatids
55
After completion of s-phase in Meiosis, how many sister chromatids are found in a human germ cell?
92 sister chromatids
56
With identical twins, 1 egg is fertilized with:
1 sperm, zygote divides into more than 1 embryo
57
With fraternal twins, 2 eggs are fertilized with:
1 sperm, two unique zygotes
58
Semi-identical twins:
1 egg, two sperm
| Identical on mother's side, but share only half of father's DNA
59
Monosomic & trisomic can occur from:
Nondisjunction
60
Monosomic:
n-1
61
Trisomic:
n+1
62
Hermaphroditic reproduction is considered:
Sexual reproduction
63
The difference between genotype and phenotype is:
Genotype is the genetic make-up of the organism while phenotype can be a physiological feature of the organism
64
Organis A has the allelic make up "AA" while B is "aa". The progeny of these two organisms are Aa. Based on this information I can say the following:
Organisms A & B are homozygous while the progeny are heterzygous
65
Blended theory vs. Particulate theory.
Blended- determinants lose individuality, can't be separated
| Particulate- determinants remain intact, can be separated
66
What is Mendel's Law of Segregation?
Two copies of a gene segregate such that each gamete receives only 1 copy of the gene
67
What is Mendel's Law of independent assortment?
Copies of different genes assort independently of one another
68
Who composed a coupling between alleles?
Bateson
69
Two genes are closely associated on the same chromosome and do NOT assort independently.
Genetic linkage (Thomas Hunt Morgan)
70
Snapdragon example where neither the red or white alleles are dominant is an example of:
Incomplete dominance
| NOT an example of "trait blending"
71
Blood type shows what type of dominance (A&B Type)
Codominance
72
Single gene, multiple phenotypic effects:
Pleiotropy (white cat, blue eyes= deaf/ pigment is linked to hearing)
73
Gene interactions affect phenotype:
Epistasis (Multiple different looking horse siblings)
74
Genotype proportion that shows phenotype:
Penetrance (Breast cancer)
75
Continuous variation, blending characters:
Multifactorial traits
76
When does nondisjunction happen in Meiosis?
Anaphase I or II
77
A transfer RNA (tRNA) contains a(n):
Anticodon
78
One way to generate different versions of mRNA is by:
Alternative splicing
79
An individual having 44 autosomes and one X-chromosome would be classified as:
Aneuplidy & have turner syndrome
80
Why can transfer RNA (tRNA) be referred to as a “bridging” molecule?
It binds to both amino acids and mRNA
81
Individual that carry a non-functional allele or potentially harmful allele without suffering consequences are:
Carriers
82
He injected mice with serial killer bacteria and nice bacteria
Frederick Griffith
83
He dissected the serial killer bacteria
James Lionel Alloway
84
This experiment demonstrated that DNA is where genetic information is stored.
Avery-Macleod-McCarty Experiment
85
What found out that DNA was a polymer of nucleotides?
Chargaff's Experiment
86
Who discovered the double helix?
```
Francis CRICK
James WATSON
Maurice WILKINS
Rosalind FRANKLIN
1953
```
87
What is a telomere?
Located at the ends of eukaryotic chromosomes
Maintains the integrity of chromosome
Have a special nucleotide sequences: TTAGGG and is repeated 100-1,000 times
88
Change in sequence without changing in length.
Point mutation
89
Large scale mutations are referred to as, and what do they consist of?
```
Chromosomal mutations
Insertion
Deletion
Inversion
Translocation
```
90
What is the difference between a translocation mutation and chromosomal crossover?
Crossover happens with homologous chromosomes
91
The removal of introns and connecting exons is called:
Splicing
92
What carries out the unwinding of the DNA and synthesis of messenger RNA (mRNA)?
RNA polymerase
93
What are polypeptide chains synthesized by?
Ribosomes
94
How many different amino acids are there?
20
95
Multiple ribosomes on a single mRNA
Polysome
96
What is tRNA made up of?
RNA
97
How many nucleotides does it take to code for an amino acid?
3 nucleotides= 1 amino acid
98
Each nucleotide triplet in mRNA is known as a:
Codon
99
This is the complete set of codon-amino acid mappings
The genetic code (20 amino acids=64 possible codons)
100
What is usually the start codon?
AUG=met
101
What are the stop condons?
UGA, UAA, UAG
102
The information encoded in mRNA is used to synthesize proteins
Translation
103
What are the translators of the genetic code?
tRNA
104
What are ribsomes made up of?
Proteins & ribosomal RNA
105
Where are ribosomes synthesized?
Nucleolis
106
What consists in the regulatory sequences of transcriptional regulation?
Non-coding DNA segments
- Promoters
- Enhancer
- Silencer
107
What consists in the transcription factors of transcriptional regulation?
Proteins
| Activators & repressors
108
Facilitate the binding of the RNA polymerase enzyme to the start position of the gene
Promoter
109
RNA polymerase needs to be activeated by a transcription factor called, some bind to the regulatory region of DNA near promoter, some bind to enhancer region
Activator
110
Inhibits the activation of transcription , prevent activators from binding to DNA, some interfere with molecular interaction with activator and RNA polymerase
Repressor
111
Region of DNA upstream of the gene itself, before the "START" codon
Operator
112
Region of DNA that increases the rate of RNA transcription
Enhancer
113
Region of DNA tha slows down RNA transcription
Silencer
114
Through the way a gene is spliced it can:
Make up multiple proteins
115
Able to turn of genes off by inactivating mRNAs (attack dog)
MicroRNA
