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Bio Final Exam (All combined)

Terms in this set (103)

gap 1 checkpoint
makes key decision on whether the cell should divide, delay division, or enter a resting stage
gap 2 checkpoint
assess the success of DNA replication, triggers start of M phase
synthesis
DNA replication
mitosis
cell and nuclear splitting
M checkpoint
accuracy of mitosis is assessed here, occurs during metaphase, triggers the exit from mitosis and cytokinesis and the beginning of G1
G0 phase
"rest stop" where cells go to stop dividing
What crosses over in meiosis
Two homologous chromosomes (lined up next to each other) exchange DNA between adjacent homologous chromatids → is part of what makes each sperm/egg unique
After it has happened, the sister chromatids of one chromosome are no longer identical to one another
Gap 2
additional growth and normal functions
Gap 1
The first part of interphase: the cell grows and functions. Also known as G1
Synthesis Phase
a cell's DNA is copied during this phase. at the end of this phase, each chromosome consists of two chromatids attached at the centromere
Mitosis
cell division in which the nucleus divides into nuclei containing the same number of chromosomes
What is the first phase during the cell cycle
G1
Time interval for gap 1
11 Hours
Time interval for Synthesis
8 hours
Time interval for Gap 2
4 hours
Time interval for Mitosis
1 hours
Total hours of cell cycle
24 hours
What would happen if g1 results in problems
Not enough organelles proteins and enzymes, cant reproduce, no growth
What would happen if Synthesis results in problems
Mutation would double
What would happen if Gap 2 results in problems
Less organelles protiens and enzymes would be made, no mitosis
What would happen if Mitosis results in problems
Cells/ nuclear material (one cel would have 2 nuclei but one would have none) wouldnt divide
What would happen if Gap 0 results in problems
Potential to get cancer/ mutated cells
Apoptosis
process of programmed cell death
what is Gap 0
A stage were cells are unlikely to/never divide
Cytokinesis
Division of the cytoplasm during cell division
Interphase contains
Gap 1, Synthesis, Gap 2
Interphase
Period of cell growth
Prophase
Chromosomes become visable, nuclear envelop dissolves, spindle forms
Metaphase
Chromosomes line up in the middle of the cell
Anaphase
Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell
Telophase
After the chromosome seperates, the cell seals off, Final Phase of Mitosis.
Griffith's experiment
Reported in 1928 by Fredrick Griffith, was the first experiment suggesting that bacteria are capable of transferring genetic information through a process known as transformation
Avery experiment
genes are composed of DNA
Hershey and Chase
concluded that the genetic material of the bacteriophage was DNA, not protein.
Franklin, Watson, and Crick
discovered the structure of DNA
DNA structure
double helix
Who discovered dna is a double helix
Watson and Crick
Griffith's Mice Experiment
Showed evidence of transformation, smooth= dead, rough=live, heat killed smooth=lived, rough and heat killed smooth= dead
What holds the nucleotides together to form each strand?
phosphodiester bonds between sugars + phosphates hold adjacent nucleotides together
What are the names of the bases and which ones form hydrogen bonds with each other?
adenine binds to thymine, cytosine bonds to guanine
→ cytosine can forms a TRIPLE hydrogen bond with guanine, adenine forms a DOUBLE hydrogen bond with thymine
Why do we say that the strands are antiparallel?
strands in opposite directions → 5' corner is opposite to the 5' corner, 3' corner is opposite to the 3' corner (see on diagram on previous slide)
Why do we say that the 2 strands are complementary?
not identical to each other, each nucleotide on the strand has its complement on the other side
cancer
mutation and growth of unwanted cells that aren't apoptated
How might the DNA damage go on to affect the rest of the cell cycle if apoptosis did not occur?
the cell has mutations so it might not go through the cell cycle correctly or two cells may be formed that each contain the mutation
cyclin-dependent kinase
enzyme to which cyclin binds during interphase and mitosis, triggering and controlling activities during the cell cycle
What can happen after several cell cycles to an organism whose damaged cells did not go through apoptosis?
a tumor may develop when cells keep dividing when they are not supposed to
Why might it be beneficial to an organism for damaged cells to enter g0 instead of dividing once they exist?
the cells would not duplicate and pass on their harmful mutation
Spindle checkpoint
ensures that all of the chromosomes are attached to the spindle in preparation for anaphase
How does human activity affect species diversity?
Make ecosystems have less biodiversity (see previous question for more info)
Hybridization (crossbreeding)
- affects species diversity
Habitat destruction/fragmentation
reduces carrying capacity for species of different ecosystems - less biodiversity
Mitotic index
Ratio of dividing cells to the total number of cells
The connection to the cell cycle and how it affects the cell cycle
Makes the cell cycle uncontrolled/not regulated properly → ultimately creates a tumor
Cancer
→ develops when cells lose the ability to regulate their cell cycle
When cell cycle not regulated, the cell continues to divide out of control and all daughter cells will do the same
DNA
Double stranded
Contains thymine not uracil
Deoxyribose sugar
"Main instructions"
RNA
Single stranded
Contains uracil not thymine
A = U
Ribose sugar
"Copy of instructions
Where does Transcription happen
- in the nucleus
Where does Translation happen
- in the cytoplasm
Translation
→ genetic code is translated into the language of proteins
mRNA travels to the ribosome where it is read and translated (changed) into an amino acid sequence
Analogy for translation
Analogy - English to Spanish
Transcription
→ genetic code is copied
DNA base sequence (code) needs to get copied into the mRNA (messenger RNA)
Will become a complementary copy of the gene
Transcription is important since it converts/copies the double-stranded DNA into a single-stranded mRNA that can leave the nucleus
DNA is too large to leave the nucleus
mRNA is going to the ribosome, tRNA reads mRNA at the ribosome and leaves the correct amino acid
mRNA can take the code into the cytoplasm for protein synthesis
Analogy for transcription?
Analogy - English in NYC and English in Texas
Environmental sources for mutation
(e.g. chemicals, UV radiation, X-Ray radiation)
One Gene One Protein Theory
Each base sequence (GENE) codes for one protein
Proteins then make up our traits
Point mutations
→ a change in just one base pair
Substitution - one base is exchanged for another
Insertion or deletion - addition or loss of a nucleotide in the base sequence
What is a mutation?
Mistakes in DNA (base pair sequence)
Can range from a single base pair (A-T or C-G, point mutation) to large chromosomal mutations
How dna replication occurs (very basic)
Bonds between the bases are broken, DNA molecule is "unzipped" → creates two separate strands
Individual bases find their match on each single strand of DNA; each strand is a template (pattern) for the base pairing
Hydrogen bonds between the bases are formed
Where dna replication occurs
nucleus for eukaryotes
cytoplasm for prokaryotes
When dna replciation occurs
During the synthesis phase
Bonds that hold sugars and phosphates together
Phosphodiester bonds
Components that make up DNA
2 strands
Each one is made up of nucleotides
Each nucleotide contains a sugar, a phosphate and 1 base
Watson and Crick
built the first model of DNA, never collected data, found out what it looked like through Franklin's experiments and other studies
Franklin and Wilkins
used x-ray crystallography to look at DNA, got chromosomes to uncoil, so she can bounce x rays off of it, gave us insight on how the shape/structure may be like
Chargaff
Adenine = Thymine
Cytosine ☰ Guanine
Hershey & Chase
- They observed the reaction of bacteriophage with the bacteria E. Coli
→ when bacteriophage with radioactive DNA injected cells, the cells became radioactive
→ when bacteriophage with radioactive protein (no radioactive DNA) infected cells, the cells did not become radioactive
Avery -
injected rough pneumonia bacteria into mice → different conclusion -- added to Griffith's experiment by finding out that it was DNA that was transferred
Griffith
- injected mice with rough (R) and smooth (S) bacteria
→ when injected with rough, they lived (rough is not harmful)
→ when injected with smooth, they died
→ when injected with heated smooth, they lived
→ dead smooth + live rough = mice died - they died because genes from the dead S bacteria went into the live rough - produced live smooth bacteria

concluded that dead cells DNA/bacteria can transfer to live cells DNA/bacteria and transform them (knew there was a transfer didn't know it was DNA yet)
Mendel's monohybrid cross and what he learned from it
learned through the monohybrid cross that one factor (dominant factor) can mask the effects of a recessive factor
Homozygous → Two alleles that code for the same thing
E.g. A person who is homozygous got the same allele from both parents (tt or TT)
Recessive → The allele that is masked by the dominant allele
not expressed in the phenotype when matched with the dominant allele
Alleles → A small section of a chromosome that codes for a specific gene
Heterozygous → Two alleles that code for different things (Tt)
Genotype → The alleles that code for the trait
Example genotypic ratio -- 1TT: 2 Tt : 1tt
Phenotype → Physical traits that the genotype codes for
Example phenotypic ratio -- 3 tall: 1 short
Sex cells/gametes
= 23 chromosomes
Somatic cells (human body cells)
= 46 chromosomes
Alleles
→ A small section of a chromosome that codes for a specific gene
Genes
→ segment of DNA, code for a particular protein that then codes for a trait
Chromosomes
→ made of DNA wrapped around proteins, all of the genetic
Allele
→ variant form of a given gene
Gene
→ a segment of DNA that codes for a particular protein which in turn codes for a trait
Chromosome
→ double-stranded piece of DNA containing genes
The final products of meiosis
FEMALES:
1 egg + 3 polar bodies (4 daughter cells)
genetically unique
Haploid gametes (23 chromosomes)
MALES:
4 daughter cells (sperm)
Genetically unique
Haploid gametes (23 chromosomes)
What is meiosis?
Process that results in the formation of sperm and egg cells
Preceded by interphase - DNA replicates and each chromosome becomes doubled, consisting of 2 identical strands of DNA
Involves 2 divisions
Meiosis I → halves the number of chromosomes
Meiosis II → sister chromatids are split
End result = 4 haploid cells
Like mitosis, but prophase/metaphase/anaphase/telophase TWICE
What is crossing over?
Two homologous chromosomes (lined up next to each other) exchange DNA between adjacent homologous chromatids → is part of what makes each sperm/egg unique
After it has happened, the sister chromatids of one chromosome are no longer identical to one another
null hypothesis
a statement or idea that can be falsified, or proved wrong
independent variable
The experimental factor that is manipulated; the variable whose effect is being studied.
dependent variable
The outcome factor; the variable that may change in response to manipulations of the independent variable.
When do you reject the null
P<0.05
monohybrid cross
A cross between individuals that involves one pair of contrasting traits
What is the probability of a yellow pea plant and heterozygous pea plant providing a yellow offspring?

G=Green
.g=yellow
50% chance yellow
Picture of prophase
Picture of metaphase
Picture of anaphase
Picture of telophase
Bonds that hold Sugars and phosphates together
Phosphodiseter bonds
bonds that hold nulceotides and strands together
hydrogen
insertion mutation
an extra base is added
the shape of dna before its supercoiled
double helix
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