Bio Test 3 Flashcards
(109 cards)
1
Q
What’s the structure of DNA?
A
- Phosphate group,
- Sugar (deoxyribose),
- and a nitrogenous base
2
Q
Possible nitrogenous bases for a DNA?
A
- Adenine,
- Thymine,
- Cytosine,
- Guanine
3
Q
What was Griffins discovery?
A
- Killer bacteria transform non leathal bacteria to killers.
4
Q
DNA is responsible for…. not ….
A
- …transformation… protein…
5
Q
What DNA bases ALWAYS bind together?
A
- Adenine always to Thymine
- Cytosine always to Guanine
6
Q
Why do the same DNA bases always bind together?
A
- Chargaffs rule:
- Equal nr of bases A and T equal the nr of bases C and G
7
Q
How are the nitrogenous DNA bases connected?
A
- By hydrogen bonds
8
Q
If there are 2000 bases in a chromosome strand and 300 of those are the base Adenine, how many Guanine bases are in the strand?
A
- 700
- (Reasoning: 300-A/ 300-T/ 1400=C+G→ C-700/G-700)
9
Q
Explain the process of DNA separation: (4 steps)
A
- Double-Stranded DNA molecule being replicated
- Strands unwind and separate
- Each strand is a template that attracts and binds complementary nucleotides, A with T and G with C
- Each double-stranded DNA molecule consists of one parental and one daughter strand, as a result of semi conservative replication
10
Q
Why does DNA split in half? What does it promote?
A
- Diversity
- Efficiency
11
Q
If the NDA sequence on one side is TGGCTAAGC, what is the order of the bases that would be added on in replication?
A
- ACCGATTCD
12
Q
Enzymes in DNA replication?
A
- Multiple enzymes and energy are needed
- Repair, and correct mistakes in the process
13
Q
Where does prokaryotic cell DNA division occur?
A
- In bacteria and Archaea
14
Q
Mutation of cells can be…?
A
- Can be good,
- Can also lead to cell death or cancer
15
Q
To know about Mitochondrial DNA?
A
o Circular DNA
o From a single lineage from your mom
o Makes proteins for the Mitochondrion
o We can map a family tree using the mitochondrial DNA
16
Q
When can cancer form?
A
- Cancer cells can form when genes coding for proteins that control cell replication are damaged and the cell divides uncontrolled forming a tumor
17
Q
Components of a Protein-?
A
- Made up of several 100 amino acids
- Polypeptide strain
- If Amino Acids are ever mixed up from its original order then it will make up a different protein
18
Q
3 types of RNA:
A
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA( rRNA)
19
Q
Messenger RNA (mRNA)
A
- Nucleus, migrates to ribosomes in cytoplasm
- Carries DNA sequence info to ribosomes
20
Q
Transfer RNA (tRNA)
A
- Cytoplasm
- Provides linkage between mRNA and amino acids; transfers amino acids to ribosomes
21
Q
Ribosomal RNA( rRNA)
A
- Cytoplasm
- Structural component of ribosomes
22
Q
What is different between mitochondrial DNA and Nuclear DNA with respect to how it is passed down from parent to child?
A
- Nuclear DNA is inherited from all ancestors
- Mitochondrial DNA is inherited from only the mother
- Mitochondrial DNA is circular.
23
Q
Organelles and other players involved in protein synthesis?
A
- DNA,
- messengerRNA,
- transferRNA,
- ribosomalRNA,
- nucleus,
- rough endoplasmic reticulum,
- golgi apparatus,
- cytoplasm,
- amino acids
24
Q
What are the differences between RNA and DNA?
A
- RNA is not double stranded,
- RNA does not contain genetic info,
- RNA has eurocel instead of thynem.
- Sugar group, DNA: deoxyribose, RNA: ribose
- Nitrogenous bases: DNA: ATCG, RNA: AUCG
25
Messenger RNA
- Functions in nucleus
- Migrates to ribosomes in cytoplasm
- Carries DNA sequence info to ribosomes.
26
Transfer RNA
- Functions is cytoplasm
- Provides linkage between messenger RNA and amino acids: transfers amino acids to ribosomes
27
Ribosomal RNA
- Functions in cytoplasm
- Structual component of ribosomes
28
In the nucleus:
- DNA unzips (weak hydrogen bonds between the nucleotide bases)
- RNA nucleotides bind with their complimentary DNA bases
- RNA strand releases from DNA (DNA zips back up)
- RNA is fine tuned by removing the introns (unnecessary nucleotides for the protein): the final RNA strand is now called mRNA and it leaves the nucleus
29
In the cytoplasm:
1. mRNA enters rRNA (ribosome)
2. tRNA hooks up with amino acids (one tRNA for one amino acid)
3. rRNA is found associated with rough endoplasmic reticulum
4. tRNA transfers an amino acid to mRNA based on the 3 letter codon (3 nucleotides)
- - a. T-RNA is important as it picks up a specific amino acid.
- - b. There are multiple codons for most amino acids
5. completed peptide strand enters rough e.r. then it is sent to the golgi apparatus to
become a completed protein and to find out its final destination.
30
If the DNA sequence is TACCCTTCAGCA, what would be the mRNA sequence?
• AUGGGAAGUCGU (its mRNA not DNA – so use the U’s)
31
Why is gene regulation necessary?
* ATP
* Don’t let RNA transcribe DNA
* Most energy saving is stopping transcription at the top
* Regulating protein synthesis
32
Prokaryotes Vs. Eukaryotes
o Prokaryotes:
* No nucleus
* Bacteria
* Why do we need RNA to code for the amino acids? → the codons for the the amino acids are in the RNA not DNA → there are no U’s but T’s
* No mRNA editing
* Single celled
o Eukaryotes:
• Multicellular
33
Red blood cells make what?
- hemoglobin
34
4 different ways to modify protein
* Transcription factors-chromatin and DNA modifications
* Alternative splicing
* mRNA export from nucleus mRNA stability
* protein modifications protein localization
35
Porto-Oncogene?
- Regulates how fast cell cycle occurs,
- If mutated it is called cancer gene.
36
Stem cells?
- can be cloned to any cell
eg. Muscle cell, skin cell, etc
37
Potential uses and problems with gene therapy? (4)
1. Insert RNA version of normal allele into retrovirus
2. Let retrovirus infect bone marrow cells that have been removed from the patient and cultured
3. Viral DNA carrying the normal allele inserts into chromosomes
4. Inject engineered cells into patients
38
• Transgenic Organism:
o Inserting genes from one organism into another organism:
- Gee inserted into plasmid
- Plasmid put into bacterial cell
39
• Making recombinant DNA:
o Restriction enzme cuts sugar-phosphate backbones
o DNA fragment added from another molecule cut by same enzyme base pairing occurs
o DNA ligase
40
• Uses of transgenic organisms:
o Plant makes the pesticide so you don’t have to spray with pesticide. When the insect eats the corn it dies due to the toxins within the corn DNA
o vitamin-a deficiency for countries that eat a lot of rice
41
Therapeutic cloning vs. Reproductive cloning
- Therapeutic cloning: Clone eg skin cells and put it on other places where you need it.
- Reproductive cloning: Taking the nucleus from a reproductive cell and stick it into an egg and tease in.
42
Knock out a gene?
- stops transcription DNA -\> mRNA.
- Usually during the single-cell stage of life just after the sperm and egg fuse = zygote.
- Gene out forever.
43
Knockdown
- stops translation of mRNA -\> protein.
- Makes "Antisense RNA" a complimentary strand to part of mRNA.
44
Antisense RNA
- A complimentary strand to part of mRNA.
- double stranded mRNA can not go through the ribosome because it need to bind with the mRNA
45
Why is cell death important for the health of an organism? And what is this process called?
- Called Apoptosis
- Removing cells
- Mistakes are made in the DNA,
- Cells no longer function like they used
- White blood cells digest bad cells.
46
What are the stages and result of Cell Division?
- Interphase
- Mitosis
- Cytokinesis
- The Result: a cell produces 2 daughter cells identical to one another; the number of chromosomes in the cell is maintained.
47
Interphase:
- Chromatin (chromosomes that were stretched out thin) is condensed by coiling, now called chromatid.
## Footnote
- Chromatids (hick chromosomes) are replicated (2 copies of the DNA) and the two copies are held together at a centromere (sister chromatids).
48
Mitosis
- Duplicated chromosomes are pulled apart in the cell by the centrosomes.
49
Cytokinesis:
The cell divides.
1. Cell wall: cell plate forms and cell divides, each with a single nucleus
2. No cell wall: cleavage furrow forms and cell divides, each with a single nucleus
50
Mitosis: why do you need this process?
o Replace dead cells
o Growth
51
• What is the order of the mitosis phases?
o Prophase, Metaphase, Anaphase, Telophase
## Footnote
52
• Meiosis
o Parent cell (spermatocyte & oocyte) → divide homologous chromosomes → 2 daughter cells with ½ the number of chromosomes → divide replicated chromosomes → 4 cells genetically unique
53
Prophase is pretty much combined with what?
-Prometaphase.
54
2 Different Types of Tumors
- Benign Tumor – not bad
- Malignant Tumor - bad
55
Prophase (mitosis)
- First stage in Mitosis
- Spindle fibers begin to form, from centrioles
- Sister Chromatids become visible
56
Metaphase (mitosis)
- Second stage of Mitosis
- Chromosomes line up along metaphase
57
Anaphase (mitosis)
- Third stage of Mitosis
- Centromere of each chromosome are pulled apart by the spindle fibers
- Sister chromatids separates
- Daughter chromosomes are created.
58
Telophase (mitosis)
- Fourth and last stage of Mitosis
- New nuclei form around new chromosome
- Spindle fibers disappear
- Cytokensis begins
59
Genetically Identical Population:
-Asexual Reproduction
60
Genetically Diverse Population:
-Sexual Reproduction
61
Cell Division with Meiosis:
Interphase, Meiosis 1, Cytokinesis, Meiosis 2,
-Result: a diploid cell produces 4 haploid daughter cells, each is genetically unique
62
Chromosomes
- Made of two sister chromatids
- Held together by centremene
63
Interphase (Meiosis)
- Chromatin (chromosomes stretched out thin) is condensed by coiling, now called chromatid.
- Thick chromosomes are replicated (2 copies of the DNA) and the two copies are held together at a centromere (sister chromatids).
- Homologous chromosomes come together (sometimes the homologous chromosomes exchange genetic information in a process known as genetic recombination)
64
Meiosis I:
- First Division
- Homologous chromosomes are pulled apart
- Each chromosome still has its duplicated copy attached: sister chromotids
65
Cytokinesis (first cell division) (Meiosis):
-The cell divides
66
Meiosis II:
- Second division
- Duplicated chromosomes are pulled apart (similar to mitosis)
67
Cytokinesis (Meiosis) (second cell division):
- Cell divides second time.
68
Result of Meiosis:
- A diploid cell produces 4 haploid daughter cells, each is genetically unique
69
Meiosis produces?
-egg and sperm
70
Why have sex?
- Genetic diversity
- Survive – different “talents”
71
What happens with the chromosomes in meiosis only?
- They pair up (Homologous chromosomes paired together)
72
Chromosome pairs 1-22 are called?
- Autosomal chromosomes
73
Chromosome pair 23 is called?
- The sex chromosome.
74
What is a X-linked disorder? Examples?
- When the gene is carried on the X chromosome and not the Y chromosome,
- ex: hemophilia. Baldness, red/green color blindness etc.
75
What cell goes through Meiosis?
-Only germ cells (found in ovaries and testes)
76
What is ovary?
- when eggs are produced, before birth
77
When does the down syndrome mistake happen?
- Meiosis 1
78
LIST THE CHARACTERISTICS OF MITOSIS AND MEIOSIS!!!
Mitosis: Meiosis:
- Body cells……………....………… Gametes
- 1 cell division
………...….……….. 2 cell divisions
- 2 daughter cells……….….……… 4 daughter cells
-
46 chromosomes
……...…………. 23 chromosomes
- Genetically identical to parent…. Genetically unique
79
How many polar bodies has 1 functional egg?
- Three!
80
About asexual reproduction?
- takes 1 individual for asexual reproduction.
- offspring are exactly the same as the parent.
- Mostly plants.
81
Embryonic stem cells
- can be formed to any cell
82
Allele Possibilities:
* Dominant Allele
* Recessive Allele
* Genotype: allele combination of a gene (two versions of a gene)
• Possible combination for a genotype (each gene is made of 2 alleles):
o GG: Homozygous Dominant
o Gg: Heterozygous (hetero-different)
o gg: Homozygous Recessive
83
How many alleles is a gene made of?
- Two
84
What’s the difference between Genotype and Phenotype?
- Genotypeis the allele combination of a gene
- Phenotype is the outcome, outward ezpression of a gene
85
Dominant and recessive genes:
- Homozygous dominant (TT),
- Heterozygous (Tt),
- Homozygous recessive (tt)
86
Complete Dominance:
- dominant allele “hides” recessive allele in the phenotype
87
Incomplete Dominance:
- Dominant allele cannot “hide” recessive allele in the phenotype
- The heterozygous genotype results in a blended phenotype. Eg. Pink roses are mix of red and white.
88
Codominance:
- Both alleles are equally expressed in the phenotype,
- Genotype is heterozygous
- Both allele are dominant
- Both alleles are expressed,
eg. Rd and white stripes on flowers.
89
What are the 3 possible alleles for human blood type?
- 2 dominant alleles IA, and IB,
- and a recessive allele i,
- plus a 4th allele: the rh‐factor gene, allele D
90
Tay-Sachs Disease
- the 4-5 year old child breaks down and die
91
Pleiotropy:
- A single gene affects more than one trait
-
Ex. Marian's syndrome,
Potential affects like being very tall, elongated fingers...
92
Sickle-cell anemia:
- Transmission of a recessive disorder
- Sickle-celled and malaria are found at same places.
-heterozygous for sickle-cell -----\> resistant to malaria, but there are still many carriers.
93
MULTIPLE ALLELES
- More than two alleles exist for a gene.
- Most known is the human blood type
94
The human blood type?
- IA= type A receptor on a red blood cell (RBC) surface (Dominant)
- IB = type B receptor on RBC surface (Dominant)
- i = Neither type on RBC surface. (Recessive)
95
What are the possible blood types for a person with B+?
- IB IB D D,
- IB i D D,
- IB IB D d.
- IB i D d,
96
What’s the Rh if genotype of blood is positive/neg?
- Positive = DD or Dd
- Negative = dd
97
Where are receptors found on Rh positive?
- on the red blood cells
98
Where are receptors found on Rh negative?
- No receptors, But they make antibodies that recognize the receptor.
99
What blood type can O+ receive blood from?
O+ and O-
| (Remember to include your own)
100
If a woman is blood type B and child is type O. What are the father’s possibilities?
-A, B, O
101
If a woman is blood type AB and child is type A. What are the father’s possibilities?
- Any!
102
What is polygenic trait?
- When one gene makes one effect
- Eg. Hair flow, skin color, height…
103
When do the homologous chromosomes separate?
- During Meiosis I
104
When do the sister chromatids split apart?
- During meiosis II
105
What is the difference of Spermatogenesis and Oogenesis?
* Spermatogenesis- 4 functional sperm
* Oogenesis- 1 funtional egg and 3 polar bodies’
106
Blood type A
A receptors
B antibodies
107
Blood type B
B receptors
A antibodies
108
Blood type AB
A and B receptors
No antibodies
(Universal receiver)
109
Blood Type O
No receptors
A and B antibodies
(Universal donor)
