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Terms in this set (72)
What is DNA?
Deoxyribonucleic acid, hereditary molecule that is passed from parent to offspring
Where is DNA found? In what form?
DNA is found in the nucleus of eukaryotic cells in the form of a chromosome.(23 pairs)One chromosome from each pair is inherited from the biological mother and one from the father
Structure of DNA double helix
sugar-phosphate backbone, nucleotide 'rungs'
Complimentary base pairing (A,T,C,G), Hydrogen bonds
A always pairs with T
C always pairs with G
DNA Replication: Semi-conservative
Process of copying DNA molecules
-Complementary Base Pairing
-Joining (Steps 2 & 3 - enzyme DNA polymerase)
Semi: Produces two copies of original DNA molecule.
•each molecule consists of one of the strands of the original DNA molecule and a new strand.
What is needed for PCR
How does PCR use the mechanism of DNA replication that our bodies naturally have to
amplify the DNA of minute samples (i.e. blood at a crime scene)
•Can make billions of copies from a starting sample of just a few molecules of DNA
-one complete set of genetic instructions encoded in the DNA of an organism
Steps of PCR
2.Amplify mutiple STR regions by PCR
3. Seperate STRs by gel extrophoresis. Which recreates a dna sequence to compare suspects
4.Compare STR banding patterns
Purpose of PCR
What are STRs? Why are they used instead of the entire genome of a person?
STRs are sections of a chromosome in which DNA sequences are repeated.
The exact length of STR varies from person to person
Gel Electrophoresis Purpose? (DNA Profile)
An electric current applied to the gel causes polar DnA to migrate through it. Shorter fragments travel farther; longer fragments remain near the top.
The gel shows the result of three different STR regions (green, red, and blue bands) analyzed from the DNA in crime scene sample and in three suspects.
Combined pattern if STR repeats at multiple sites is unique to a person.
Forensic scientists use STRs to create a DNA profile.
What is a protein?
sequence of amino acids
Number of amino acids
•20 different amino acids
Amino side chains
is responsible for determining charge and polarity of the amino acid.
Linear sequence, 3D folding, polymer assembly
•Bond together to form linear chains
•Chain folds into a 3-D protein based on the sequence of amino acids
•shape of the protein determines its function
Changes in amino acid sequence can result in what?
•changing an amino acid in the sequence changes the 3-D shape of the protein
this changes the function as well.
Where do proteins come from? Process of gene expression.
•Instructions to make proteins are encoded by genes
─a sequence of DNA that contains the instructions to make one or more proteins
•Genes are found on chromosomes
•Each chromosome carries a unique set of genes
•Synthesis of a protein from a gene is called gene expression
What are GMOs/transgenic organisms?
Genetically Modified Organisms
•Through genetic engineering, genes from one species can be inserted into another species, creating a transgenic organism
How do we make them? (recombinant genes)
•To make transgenic silk, scientists fuse spider silk coding sequence with yeast regulatory sequence
•The combination is called recombinant gene
•A vector is a DNA molecule used to deliver a recombinant gene to a host cell
Coding vs. regulatory regions
•Regulatory sequences are on-off switches for genes
•Coding sequences determine the identity of the protein
Know how to make a recombinant gene (which regulatory and which
coding segment to put together)
Yeast and regulatory sequence is combined
Benefits of GMOs
Pesticide prtects food and we can even make antibiotics by doing this
What is artificial selection and how is it similar/different to a GMO?
•Artificial selection: selective breeding where humans choose desired traits
•Genes are not moved between organisms.
•Frequency of alleles in population is changed over generations.
What is a gene? What does it mean for a gene to be expressed?
a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
You show that gene in physical form
Two main steps- what happens in each step? Where do these steps happen?
Transcription:•occurs in the nucleus of eukaryotic cells and cytoplasm of prokaryotic cells
Translation: occurs on ribosomes in cytoplasm
molecules of messenger RNA (mRNA) are synthesized from the instructions encoded in genes
uses mRNA sequence to assemble the appropriate amino acid sequence of proteins.
Main players in gene expression
DNA -> mRNA -> protein
What enzymes are involved? What do they do?
What is a codon and how is it used to assemble a protein?
•A codon specifies a particular amino acid
Some codons specify where to start translation (start codons) and where to end (stop codons).
What is meant by redundant and universal when describing the genetic code?
There is redundancy in the genetic code, as 64 possible codons code for only 20 different amino acids. Since the genetic code is universal, the same gene will be transcribed and translated into the same protein in virtually all cells and organisms.
How can making our own organs benefit society?
No wait, less rejection percentage,
What is a tissue?
•Tissue: an organized group of different cell types that work together to carry out a particular function
What is cell division?
•Cell division: the process by which a cell reproduces itself
Why do cells normally divide?
•Growth and development
Cell Cycle What is it?
•Ordered sequence of stages
•Preparatory and division phases
•One cell to two identical cells
Stages and what happens in each stage
Stages of the cell cycle
include interphase, mitosis, and cytokinesis.
Each chromosome replicates in S phase, resulting in two sister chromatids connected at the centernomere
•chromosomes are evenly divided
•sister chromatids are separated
•enlarged cell splits into two cells
•each has full complement of DNA
•one parent cell, into two daughter cells
What are the preparatory phases?
•copy cellular contents
•duplicate organelles, DNA, and cytoplasm
•each new cell has the same amount as original cell
•G1, S, G2
What are the division phases?
mitosis and cytokinesis
What are the stages of interphase?
•cell grows, makes extra cytoplasm
•DNA replication occurs, chromosomes
•identical sister chromatids
•cell prepares for division
What are the stages of mitosis?
prophase, metaphase, anaphase, telophase
What are sister chromatids?
2 identical copies of DNA held together by a centromere
Why are the held together?
Sister chromatids are held together by proteins at a region of the chromosome called the centromere.
What structure holds sister chromatids together?
When are they pulled apart?
What results from mitosis?
The cell divides into two
What are daughter cells? How do daughter cells compare to the parent cell
Either of the two cells formed when a cell undergoes cell division by mitosis. Daughter cells are genetically identical to the parent cell because they contain the same number and type of chromosomes.
What are the phases of mitosis?
prophase, metaphase, anaphase, telophase
cromosomes coil up
Chromosomes line up in the middle of the cell
sister chromatids separate
1: Chromosomes lengthen and become indistinct chromatin
2: Nuclear envelope forms and nucleolus appears
3: spindle fibers disappear
4: 2 daughter nuclei present
5: Cytokinesis occurs (division of cytoplasm)
What are stem cells?
immature cells that divide and differentiate into specialized cell types
What do they do in our bodies
Role in development
What can we use them for?
•Organs can be regenerated with the help of stem cells and cadaver organs
What is the process of cellular differentiation?
•The process in which a stem cell develops into a more specialized cell type
What are the 4 different strategies for using stem cells to cure disease?
organs are made
inject into damaged tissue
clean donated organs before transported
Cell cycle check points What do they do?
Cell cycle checkpoint is the mechanism that ensures that each stage of the cell cycle is completed accurately
Where are they in the cell cycle?
G1, Mitosis, s
What happens when they go wrong in relation to cancer?
They dont correct the mistakes and can lead to cancer
How do mutations contribute to cancer? (BRCA example)
They can lead to non stop cell division
What are tumor suppressors? How are they different from proto-oncogenes?
Proteins that stop the cell cycle & check for errors
proto-oncogenes say to go through the cell cycle instead of stopping it.
What is apoptosis?
programmed cell death
Defining characteristics of cancerous cells
Continue to divide piling on top of one another
Stages: Benign -> Malignant -> Metastasis (which stages are cancerous?)
noncacerous, cancerous, cancerous
Treatments: Surgery, chemotherapy, radiation, targeted therapy, immunotherapy.
What does each method of treatment do?
Chemotherapy: treatment by toxic chemicals
Drugs target all dividing cells**
Radiation therapy: using ionizing radiation
Targeted therapy: specific for cancer cells and not harmful for normal cells
Immunotherapy: using the immune system to recognize cancer cells
What is a mutation? What is an allele and how are they related to mutations?
Change in DNA sequence.
-different versions of the same gene produced through mutations are called alleles
How do mutations arise? How does the cell protect against mutations? (proofreading,
cell cycle check points)
proofreading, cell checkpoints.
What is the difference between germ-line and somatic mutations? Which one is
•Occurs in gametes and is passed on to offspring.
•In every cell of the body
Somatic (sporadic) mutation
•Occurs in a body (nongamete) cell and is not passed on to offspring
•Passed only to daughter cells of mutated cell
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