CYTOGEN Flashcards
Observable characteristics; physical features, behaviors, risk of getting disease.
Traits
Transmission of TRAITS and biological information between generations.
Heredity
Study of HOW TRAITS are TRANSMITTED
Genetics
Concerned with how the chromosomes relate to cell behavior, specifically during mitosis and meiosis.
Cytogenetics
Genetic material; the biochemical that forms GENES; made of SUGAR and PHOSPHATE backbone; has 4 NITROGENOUS base pairs.
DNA
The 4 nitrogenous base pairs:
Adenine - Thymine
Guanine - Cytosine
sections of DNA that contain instructions on how to make proteins; passed from parent to offspring.
Genes
Complete set of genetic instructions characteristic of an organism.
Genome
An alternate form of a gene.
Allele
A combination of an organism’s alleles; “What is present?”
Genotype
OBSERVABLE version of a trait; “What is seen?”
Phenotype
Aids in predicting the likelihood of certain offspring GENOTYPES and Phenotypes.
Punnett Square
Meaning of CRISPR
Clustered Regularly Interspaced Short Palindromic Repeats
Tightly and continuously wound molecules of DNA and proteins; level of genetics; found during cell division; formed by two chromatids attached at the center by a centromere.
Chromosome
Level of genetics:
chromosome>DNA>gene>base pair
One of the two halves of a chromosome
Chromatid
Unwound DNA; only seen during INTERPHASE
Chromatin
Made of smaller structures called amino acids; built by cells using instructions found in genes.
Proteins
A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid; e.g., UUU codes for phenylalanine.
Codon
Any change to a DNA’s nucleotide sequence; happens when DNA is copied.
Mutation
Having 2 sets of chromosomes in EACH CELL; chromosomes are arranged in HOMOLOGOUS PAIRS.
Diploid
Having 1 set of chromosomes
Haploid
Having the same alleles
Homozygous
Having different alleles
Heterozygous
Specific location in a gene
Locus/Loci
Pertaining to the egg and sperm cell - sex cells
Gametes
Fusion of gametes from 2 parents
Fertilization
VARIATION. ADAPTATION. SURVIVAL
- “On the Origin of Species by Means of Natural Selection, or the Preservation of Favored races in the Struggle for Life”
- Heredity transfers traits from parents to offspring, maintaining these variation.
Charles Darwin
Why did Gregor Mendel use peas for his experiment?
- Control fertilization
- Shirt life cycle
- Multiple characteristics
According to Gregor Mendel, it is the units of inheritance. It is now known as gene.
Elementen
What theory did Mendel disproved?
Blending Theory of Inheritance
3 Laws established by Mendel
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
He discovered the basic principles in heredity.
Gregor Mendel
According to this law, one trait (dominant) masks the other trait (recessive).
Law of Dominance
According to this law, the traits that get passed to gametes (sperm and egg) get SEPARATED.
Law of Segregation
According to this law, genes for different features segregate INDEPENDENTLY during gamete formation; a pea plant’s height does not affect its color.
Law of Independent Assortment
Discovered “NUCLEIN” (DNA)
- Isolated DNA from the nuclei of white blood cells.
- Found the substance in the pus of surgical bandages.
Friedrich Miescher
Who discovered that chromatin is a stainable substance inside the nucleus?
Described mitosis - observed the movement of chromosomes during cell division.
Walter Flemming
“Chromosomes are the basis of heredity.”
- The reduction of chromosomes in meiosis is directly related to Mendel’s laws of inheritance.
Walter Sutton
He changed Mendel’s “Elementen” into gene.
Wilhelm Johanssen
“Chromosomes carry genes.”
He used fruit fly (Drosophila Melanogaster)
Thomas Morgan Hunt
1940s - Amino Acid Sequence of Insulin
1970s - DNA and Protein Sequencing
Frederick Sanger
Photo 51
X-ray Image DNA Fragments
Rosalind Franklin
Double-Helix of Structure of DNA
James Watson and Francis Crick
First animal cloned via nuclear cell transfer AKA cloning.
Cloned from the udder cell of a ewe.
Dolly the Sheep
First pet to be cloned.
CC the Cat
First person to sequence the bases in each codon.
Marshall Nirenberg
CRISPR-CAS9
Jennifer Doudna and Emmanuelle Charpentier
“genetics”
William Bateson
Pneumococcus experiments
Avery Mcleod, McCarthy
Bacteriophage labelling experiments
Hershey and Chase
Acc. to Wilson and Crick each DNA strand serves as template for the daughter or replicated DNA; conducted an experiment to determine which strand is the parent DNA and which is the daughter DNA.
Meselson and Stahl
Talked about sequencing the human genome.
Sinsheimer
2003-2006; made use of Sanger Sequencing.
Human genome project
An analysis of chromosomes during METAPHASE.
Karyotyping
Karyotyping is banded using:
Trypsin
Karyotyping is followed by stains such as:
Giemsa, Leishman, or both
Complete set of chromosomes of an individual.
Karyotype
Visual profile of stained (usually Giemsa).
Karyogram
- Useful in making karyogram - a graphical depiction of a karyotype.
- Giemsa binds to PO4 groups in DNA where there is high Adenine-Thymine bonding.
- Identifies: chromosomal aberrations such as trnaslocations and rearrangements.
G-banding (Giemsa)
- Stains heterochromatin near centromere.
- Treat with ACID, then alkali.
- Uses Giemsa stain.
C (Centromere) banding
- Quinacrine stain creates FLUORESCENT bands.
- Needs UV fluorescent microscope to view bands.
Q (Quinacrine) banding
- Highlights satellites and stalks of acrocentric chromosomes (having off-center centromere)
- Uses SILVER stain.
NOR (Nuclear Organizing Region) stain
- Blood Collection
- Cell culture
- Stopping cell division @ METAPHASE
- HYPOTONIC treatment of blood cells.
- Fixation
- Slide preparation
- Slide dehydration
- Enzyme treatment
- Staining
Steps in Karyotyping
For: detecting and locating a specific DNA sequence.
How it works: full set of chromosomes from an individual is affixed to a glass slide and then exposed to a “probe” (small piece of purified DNA tagged with a fluorescent dye)
Probe finds and then binds to its matching sequence within the set of chromosomes.
A microscope is used to view the location of the probe.
Application: for understanding chromosomal abnormalities and other genetic mutations.
FISH (Fluorescent In-Situ Hybridization)
In a nutshell: used to determine whether genes are on or off.
Determines whether DNA from an individual has a mutation or not.
Steps:
1. DNA in the sample is denatured, DNA separates into 2 strands.
2. DNA is cut into smaller pieces.
3. Smaller pieces of DNA are labeled with a fluorescent dye; RED for control/normal; GREEN for pt DNA.
4. Pt DNA and ctrl are inserted into the chip and allowed to hybridize or BIND to synthetic DNA on the chip.
5. Results:
NO mutation: red and green samples bind to the chip sequence without mutation.
WITH mutation: green sample will not properly bind to the normal sequence on the chip; instead, it will bind to the sequence with mutation.
DNA Microarray Analysis
Organized structures containing DNA associated with structural proteins called histones.
Chromosomes
Having multiple sets of chromosomes. Can occur due to: Meiotic and mitotic failures and Fusion of unreduced gametes.
Polyploidy
- Supercoiled DNA structure
- 0.2-20 um in length
- Found in the nucleus of eukaryotes
- May be unduplicated which appear as lines.
- May be duplicated; having 2 sister chromatids attached at the middle by centromere.
- In its DIFFUSED STATES, termed as chromatin
Linear Chromosome
No nucleus, genetic material floating around.
Prokaryotes
- Found usually in prokaryotes.
- Except in Borrelia burgdorferi (CA of Lyme disease), which has a single LINEAR CHROMOSOMES.
- Found in the nucleoid region.
Circular Chromosome
Nucleated + Organelles
Eukaryotes
4 Cellular Components
Carbs
Proteins
Lipids
Nucleic Acids
Contains genetic material (DNA); separates DNA WITHIN the cell.
Nucleus
Factory for ribosomes
Nucleolus
Site of protein synthesis
Rough Endoplasmic Reticulum
Ribosome
Site of lipid synthesis
Smooth Endoplasmic Reticulum
Temporarily stores or transports substances
Vesicles
Where sugars are made, linked into starches or joined LIPIDS AND PROTEINS where proteins finish folding; packages secretions into VESICLES that exit via plasma membrane.
Golgi Apparatus
Degrades debris; deals with waste by RECYCLING cell contents.
Lysosome
Cell’s way of disposing its own trash.
Autophagy
Vesicle that forms from plasma membrane carries LDL to lysosomes.
Endosome
Vesicle that transports molecules between cells.
Exosome
Breaks down and DETOXIFIES various molecules; abundant in kidneys and liver.
Peroxisome
Releases energy from nutrients.
Mitochondria
Phospholipid BILAYER studded with proteins that controls which substances enter and exit the cell (signal transduction) and how the cell interacts with other cells (cellular adhesion).
Plasma membrane
Cell’s skeleton
Provides framework/scaffolding
Cytoskeleton
Cytoskeleton is made up of:
Microtubules
Microfilaments
Intermediate Filaments
From tubulin; makescup cilia
Microtubules
From actin (remember actin and myosin in muscle cells which allows muscle contraction) which allows cells to withstand stretching an compression.
Microfilaments
Abundant in nerve and skin cells
Intermediate filaments
In a nutshell, during the …, cells are preparing themselves for the upcoming cell division; they’re preparing themselves for something big that’s about to happen.
Cell cycle
Phases under cell cycle
G0
Interphase (Gap 1, Synthesis phase, Gap 2)
M phase (Karyokinesis, Cytokinesis)
It is divided into 2 gap phases (G1 and G2) and 1 synthesis phase (S phase)
Interphase
Cells increase in size, makes proteins, lipids and carbohydrates as well as organelles.
G1
Time out. Resting stage. No cell division occurs. When the cell decides what to do next.
G0
DNA synthesis; cells go to do not disturb mode. DNA in chromosomes are REPLICATED.
Synthesis (S) Phase
More proteins and organelles are synthesized and the cell prepares itself for mitosis. Synth of chemicals needed for microtubule production.
G2
Cell nucleus divides
Karyokinesis
Cell itself divides into daughter cells
Cytokinesis
It regulates the cell cycle.
Proteins
Too little mitosis
Injury goes unrepaired
Too much mitosis
Abnormal growth or cancer
Cell Cycle Checkpoint:
- @G1/S transition AKA DNA damage checkpoint; cell decides whether it will divide or not.
Checks for: Cell size, Nutrients, GFs, DNA damage
Note: Is a cell does not get a go signal to continue, it enters the G0 phase, but if conditions improve, the cells will resume with division.
G1 Checkpoint
Cell Cycle Checkpoint:
- @G2/M transition AKA APOPTOSIS checkpoint: cell makes sure that cell division goes smoothly.
Checks for: DNA damage, DNA replication completeness
Note: Damage detected - pause at G2 for repair, Damage IRREPARABLE - cell undergoes APOPTOSIS; helps prevent cancer.
G2 Checkpoint
Cell Cycle Checkpoint:
- AKA Spindle checkpoint
Checks for: Chromosome attachment to spindle at metaphase plate.
M checkpoint
2 types of cells involved in cell division:
- Somatic (body cells)
- Germ/reproductive/sex cells/gametes
Do not directly participate in sexual reproduction.
Somatic or Body Cells
Mitosis occurs only in…and produces 2 daughter cells.
Eukaryotes
of chromosomes in daughter cells are theme as parent cell
Diploid
Sperm and egg
Germ/reproductive/sex cells/gametes
Meiosis; “double division”’ 4 daughter cells with HALF (…) # of chromosomes, necessary for reproduction in Eukaryotes.
haploid
Sperm (23) + egg (23) =
46 or 23 PAIRS of chromosomes.
Haploid + Haploid =
Diploid
When sperm cell and egg cell both having HAPLOID number of chromosomes unite, they COMBINE their chromosomes and RE-ESTABLISH the DIPLOID number of chromosomes. It is necessary for sexual reproduction among EUKARYOTES.
Meiosis
90% of its time is spent on this phase.
Prophase 1
Chromosomes look for their homologous pair (chromosomes with same length and centromere position)
Homology search
What paris are called after homology search?
Bivalents or tetrads
Intimate pairing
Synapsis
Exchange of genetic material between NON-SISTER CHROMATIDS of homologous pairs; guarantees GENETIC VARIATION among offspring
Crossing over
Site of genetic exchange
Chiasmata
Substages of Prophase 1
Leptotene
Zygotene
Pachytene
Diplotene
Diakinesis
Substages of Prophase 1:
Chromosomes condense; VISIBLE STRANDS in nucleus
Leptotene
Substages of Prophase 1:
Homologous chromosomes PAIR UP during synapsis/intimate pairing
Zygotene
Substages of Prophase 1:
Crossing over occurs
Pachytene
Substages of Prophase 1:
SLIGHT separation of chromosomes
Diplotene
Substages of Prophase 1:
Nucleolus disappears.
Nuclear envelope disintegrates.
Spindle fibers forms.
Diakinesis
Mitosis
Disintegration of nuclear membrane.
Disappearance of nucleoli.
DNA begins to supercoil and appear as chromosomes.
Prophase
Mitosis
Chromosomes appear as sister chromatids attached at the center by the centromere containing the kinetochore.
Centrioles appear on both poles of the cell.
Spindle fibers appear and attach to kinetochore.
Chromosomes align in the MIDDLE of the cell.
Metaphase
Mitosis
Sister chromatids are pulled APART towards opposite poles.
Anaphase
Mitosis
Nuclear membrane reappears.
Cleavage furrow begins to appear.
DNA begins to diffuse into the nucleus.
Nucleoli appear.
Telophase
Production of 2 new daughter cells after mitosis.
Cytokinesis
In (year) - accepted that there are 46 chromosomes.
1956
Cytogenetics relies heavily on basic techniques:
Karyotyping
FISH
DNA Microarray Analysis
When did Mendel published his findings?
1866
When did Mendel got credited as the Father of Genetics?
1901
Offspring that inherit a different gene variant (allele) form each parent.
Hybrid
A cross of two individuals who heterozygous for a single trait.
Monohybrid Cross
Law of Inheritance:
One trait (Dominant) masks another trait (recessive).
Law of Dominance
Law of Inheritance:
When gametes (egg and sperm cells) are formed, each of those cells DO NOT get both copies of the allele;each of then will get 1 COPY of the allele.
Law of Segregation
Law of Inheritance:
For 2 genes on different chromosomes, the inheritance of 1 gene does NOT influence the chance of inheriting the other gene.
Genes “independently assort” because they are packaged into gametes at random.
Law of Independent Assortment
Year when Wilhelm Johanssen renamed Mendel’s “elementen” into gene.
1909
A hormone which elongates the stem.
Gibberellin
The encoded protein of this gene connects sugars into branching polysaccharide molecules.
R gene
An individual with two different recessive alleles for the same gene.
Compound heterozygote
Most common expression of a particular allele combination in a population. Can be recessive or dominat.
Wild type phenotype
Variant of a gene’s expression that arises when the gene undergoes a change, or mutation. Permanent damage
Mutant phenotype
Represents how genes in gametes join if they are on different chromosomes. A diagram used to follow parental gene contributions to offspring.
Punnett Square
Crossing an individual of unknown genotype with a homozygous recessive individual; homozygous recessive is a “known” that can reveal the unknown genotype of another individual to which it is crossed.
Test cross
Single gene on chromosome 15.
Gives eye color by controlling melanin synthesis.
OCA2
If OCA2 is missing…
Albinism
Recessive allele in OCA2
blue eyes
Dominant allele in OCA2
brown eyes
Gene on chromosome 15 near OCA2
Controls expression of OCA2 gene
Recessive allele of HERC2 removes control over OCA2.
HERC2
2 recessive alleles in HERC2
blue eyes
Dominant allele is NOT completely expressed in the presence of a recessive allele.
Incomplete/Partial Dominance
Different alleles that are both expressed in a heterozygote are codominant.
Codominance
Loci (specific location) are literally in the sex chromosomes e.g. recessive trait and X-linked (like color blindness)
Sex-linked traits
genes are found on autosomes but resulting phenotypes are expressed only in EITHER gender.
Sex-limited traits
Manifested in both genders but at different degrees of expression.
Sex-influenced traits
He devised a graphical way of depicting or predicting all possible gene combinations in a cross of parents whose genes are known.
Reginald C. Punnett
Scientific name for peas
Pisum Sativum
Chromosomes 1-22
Autosomes
23rd pari of chromosomes; determine a person’s biological sex.
Sex Chromosomes
Gene masks another gene
Epistasis
Allele masks another allele of the same gene
Dominance
Pairing of homologous chromosomes
Synapsis
Single gene influences multiple traits
Pleiotropy
