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Exam 3 Chapters 12-17
Biological principles 101
31
Biology
Undergraduate 1
05/08/2012

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Term
What are Histones?
Definition
Protiens used to package DNA in eukarayotes.
Term
What are Nucleosomes?
Definition
They consist of DNA wound around histone molecules.
Term
Sister Chromatids
Definition

before a cell divides, it duplicates all of its chromosomes, resulting in two copies.

 

* They are not one of the 23 pairs. 1 of the 23 pairs would be 2 sets of chromotids.

Term
Centromere
Definition
it's a narrow waist that sister chromotides are joined together by.
Term
What are the 2 distinct phases in the cell cycle?
Definition

90%- Interphase (not spliting the cell in half)

 

10%- Mitotic Phase ( spilting the cell in half)

Term
During Interphase a cell....
Definition

- Performs its normal functions

 

- Doubles everything in its cytoplasm

 

- Grows in size

Term
In the Mitotic phase what 2 overlapping processes occur?
Definition

1. Mitosis, in which the nucleus and it's contents divide evenly into daughter nuclei.

 

2. Cytokinesis, in which the cytoplasm is divided in two.

Term
In Mitosis what are the 4 distinct Phases?
Definition

1. Prophase- Chromosomes Condense

2. Metaphase- Chromosomes Align

3. Anaphase- Chromosomes Seperate

4. Telophase- Chromosomes Relax

 

Remember -PMAT (self reminder Pacey's PMAT)

Term
In the cycle what phases does Interphase and the Mitotic phase have?
Definition

Interphase- G1, S & G2

 

Mitotic Phase- M Phase

Term
Cytokinsis
Definition

- Occurs during Telephase

- Divides the cytoplasm

- Is different in plant and animal cells 

Term
Cell Checkpoints
Definition
the cell cycle stops until a go-ahead signal is received ( think of traffic lights)
Term
What are the 3 cell checkpoints?
Definition

1. G2 checkpoint

 

2. M checkpoint

 

3. G1- which is very important, its the hardest checkpoint to get past.

 

Term
What is the cell cycle controlled by?
Definition

Cyclins and Cyclin-dependent kinases, which fluctuate with the cell phase.

 

MPH (maturation-promoting factor) is a cyclin/CDK complex that triggers the M phase.

 

It goes CDK, CDK, Cyclin MPH

Term
Growth Factors
Definition
Insulin ( which makes you fat) and hGH growth hormone
Term
What is Cancer?
Definition

* Cancer causes the loss of control of cell replication.

 

* DNA damage causes loss of messenger protiens that contro the cell cycle.

Term
What is a Tumor?
Definition
A Mutated cell.
Term
What happens when a Tumor Metastasises?
Definition
Cancer cells spread through lymph and blood vessels to other parts of the body.
Term
Meiosis
Definition

* Happens in the Ovary's and Testes

 

* Sexual reproduction that combines the genes of 2 organisms

 

When the sperm meets the egg it has 23 chromosomes -Sperm cell 23 Chromosomes - one chromosome from each pair = Fertilized egg 46 Chromosomes!

Term
Mitosis
Definition
Asexual reproduction (star fish) as well as the splitting of cells for growth and maintenance produces copies of the same gene.
Term
Karyotype
Definition

is an image that reveals an ordery arrangement of chromosomes.

 

EX- Human and horses have different Karyotypes ( theres no such thing as half man half horse)

Term
Whats the process of Meiosis?
Definition

1. Interphase- "the cross over"

 

2. Meiosis 1- 2 daughter nuclel ( sister chromids stay together)

 

3. Meiosis 2- 4 daughter nuclel

Term
Nondisjunction
Definition
members of a chromosome pair fail to separate during anaphase, producing gamets with an incorrect number of chromosomes.. it can occur in Meiosis1 or 2.
Term
Hybrids
Definition

 are the offspring of 2 different true-breeding varieties.

 

- Parental plants are- P generation

- hybrib offspring- F1 generation

- cross of F1 plants form F2 generation.

Term
Homozygous
Definition
both alleles are identical
Term
Heterozygous
Definition
alleles are different
Term
What is the Phenotype determined by?
Definition

The DOMINANT allele.

 

If a White and Purple flower have the same 2 genes they will produce purple flowers.

Term
Ressesive Disorder
Definition

* most human genetic disorders are ressesive

 

* individuals who have the ressesive allele but appear normal are carriers of the disorder.

Term
Transcription
Definition
is the synthesis of RNA using information in DNA
Term
Translation
Definition

is the synthesis of a polypeptide using information in the mRNA.

 

* ribosomes are the sites of translation.

Term
Genetic Code
Definition

* there r 20 amino acids but there are only 4 nucleotide bases in DNA.

 

* 3 nucleotides correspond to an amino acid codon.

 

64 possible combo's from 3 can be made up from ACGT.

 

A GOES WITH T

G GOES WITH C.

A GOES WITH U

 

Term
3 STAGES OF TRANSCRIPTION
Definition

*  Initiation

*Elongation

* Termination

 

(I E T)

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