• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/103

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

103 Cards in this Set

  • Front
  • Back
What does genetic make-up influence?
Future health and risk of disease.
What is genetics?
Study of heredity - the passing of physical, biochemical, and physiological traits from biological parents to their children.
How can disorders happen?
Mutations that can occur naturally or transmitted from parent to offspring, resulting in disability or death
Describe DNA
Deoxyribonucleic acid

Sugar-phosphate backbone

Bases in the middle (A, G, T, C)

Found in nucleus and mitochondria
What are chromosomes?
Double stranded DNA located in the cell nucleus.
How many chromosomes do we have? How many autosomes and sex chromosomes?
46 Chromosomes

22 pairs of autosomes

1 pair of sex chromosomes (XX, XY)
Which sex chromosome means male? Female?
Male = XY
Female = XX
What is a gamete? What does it do?
Gametes have only one of the chromosome pair (x or y).

Contains individuals genetic information that is passed to offspring.
How many bases are there in human DNA?
6 billion
What is a gene?
Hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristics in an organism.
Order of the DNA ________________ is important
bases.
The average gene has how many bases?
3,000
How many genes are there in a human?
20,000 - 30,000
What is mRNA?
A copy of dna made through the process of transcription.
What is translation and transcription?
Transcription = DNA --> RNA

Translation = RNA --> Protein
Where does translation take place?
Ribosomes.
Where are proteins synthesized?
Either on a free ribosome in the cytoplasm or a ribosome on the rough endoplasmic reticulum.
If a protein is synthesized on the RER where does it go?
To the surface (cell membrane) or outside the cell via Golgi apparatus.
If a protein is synthesized in the cytoplasm by a free ribosome, where does it go?
Targeted protein ---> Peroxisome/mitochondria

Or

Cytosolic protein, stays in cytoplasm.
What does rRNA do?
Provides a physical place of translation.
What does tRNA do?
Transfer RNA, carries amino acids to build protein.
What are the differences of DNA and RNA?
RNA = single stranded
RNA has ribose versus deoxyribose
RNA has uracil
RNA can leave the nucleus.
What is a sequence of three bases called? What does it do?
3 bases form a codon. Relate to a single amino acid.

The order of amino acids = protein type.
What is the central dogma theory?
You can determine an organism's physical, biochemical, and physiologic traits.
T/F All somatic cells have a copy of the entire genetic code.
True.
T/F all genes are expressed in all cells at all times.
False.
T/F expressed genes (aka proteins) are not active all the time.
True.
What are the two types of replication?
Mitosis and meiosis
What is the result of mitosis?
Results in two identical daughter cells.

Each cell contains 23 pairs of diploid chromosomes.
What is the result of meiosis?
Results in 4 haploid cells.

Each gamete contains 23 single chromosomes (haploid).

Male and female gametes fuse at fertilization to restore diploid number.
What is crossover? Where/when does it happen?
Crossover happens in meiotic division during metaphase I.

Allows for independent assortment to gametes (genetic diversity).
What is genomics?
Study of the human genome.
What is proteomics?
Study of different proteins produced (100,000 in the human body).
What are applications of genomics?
Health field. Pharmacogenomics and nutrigenomics.
What is a genotype?
A collection of genes.
What does phenotype mean?
What proteins are made determine function/structure.

Expression of genotype.
What is homozygous.
Same allele on both chromosomes
What does heterozygous mean?
Different alleles on both chromosomes.
Dominant/recessive.
Dominant = one allele for expression
Recessive = same alleles for expression
Punnet Square.
Know how to do it.
What does carrier mean?
Dd. Carries the gene, but does not express it.
Define mutation.
Any change in nucleotide sequence in a gene or change in chromosome.
How can mutations happen?
Spontaneously (error occurring during normal dna replication)

Or

Environmental, free radical exposure leads to damaged dna.

Or

Inherited, if the mutation is associated with a gamete it will pass down to the kid.
What does a mutation result in?
Changes in protein, since order of DNA bases determines amino acid order.

Results in ----> normal variation in humans or disease/disorder.
What is ap oint mutation?
Change in base in DNA
Where do chromosome defects happen?
During crossover or anaphase.
Can errors in DNA bases be repaired? If so, how?
Yes.

If DNA is damaged by UV light it can be repaired by photolyase (cleaves thymine dimer) or nucleotide excision repair (cuts out the regain containing thymine dimer).
If an error in DNA base is not repaired, what can happen?
Defective cell may recognize it as damaged and undergo apoptosis or be cleared by immune cells.
Why are some DNA errors not repaired?
Overwhelming/prolonged exposure

Poor health/immune/nutrition status.

Not determined to be detrimental to body.
What are the outcomes of mutation?
May not result in a different DNA sequence (silent mutation, because it resulted in the same amino acid).

May result in difference DNA sequence and therefore different protein.
If the outcome of a mutation is a different protein, what can happen?
1) No change to cell function

2) change in cell function, but not deleterious.

3) Change in cell function is deleterious, can cause cell death or local/systemic impact.
What is penetrance?
Percentage of the individuals genotype who expresses the phenotype.
What is expressivity?
Extent to which a given genotype is expressed at the phenotypic level.
What is incomplete dominance?
One allele for specific trait is not completely dominant over the other allele.

Results in combined phenotype.

Example: Curly + straight hair = wavy hair
Sickle cell anemia.
What is co-dominance?
Both alleles of the gene pair in a heterozygote are fully expressed. Neither one being dominant or recessive to the other.

Example: Blood type.
What does sex-linked mean?
Mutation that occurs on the sex chromosomes (X or Y).
In sex-linked mutations, which chromosomes are most linked to?
X
Are sex-linked mutations usually dominant or recessive?
Recessive.
Who is more likely to be affected by sex-linked mutations?
Males.

Example: Color blindness.

Males are XY and therefore only need one gene to express the gene.
What is mitochondrial gene disorder?
Mutation in mitochondria dna that often results in ATP production problems.
Where does mitochondria gene disorder come from?
Matrilineal inheritance, comes from mom.
How much of the DNA does mitochondria DNA make up?
1% of the total DNA.
What is heteroplasy?
Not all dna in the mitochondria are affected, so manifestations of a disorder don't appear until a certain % of the mtDNA is affected.
What is an example of mitochondria gene disorder?
MELAS (mitochondrial encephalopathy, lactic acidosis, stroke.
How does MELAS happen?
Multiple mutations in mtDNA. 8point and 1 deletion mutation.

Substitute A with G in 80% of cases.
What happens in MELAS?
Result is defective cytochrome oxidase. Impaired oxidative metabolism. Must rely on anaerobic respiration. Decreased production of ATP.
About how much of mtDNA needs to be mutated before symptoms appear?
About 50% of the mtDNA.
If you have MELAS, what age does it usually appear?
10 years old.
Symptoms of MELAS?
hearing loss, blindness, migraines, nausea, short stature.

Hemiplegia (paralysis), cardiomyopathy/myopathy, diabetes.
What is the treatment for MELAS?
Symptomatic (cochlear implants).

Pharmacologic
Reduce seizures (anticonvulsants)
Promote mitochondria energy production (coenzyme Q, riboflavin, creatine).

Experimental: Dichloroacetate to convert pyruvate to acetyl-CoA versus LA.
What is the average lifespan of someone with MELAS?
<45.
What is a chromosomal alteration?
A loss, addition, or rearrangement of chromosome parts (affecting many genes).

Often happens to do nondisjunction.
What is nondisjunction?
Alteration of chromosome number due to failure of chromosomes to separate correctly during cell division.

Unequal number of chromosomes between cells.
What are the three forms of nondisjunction? Describe them.
Monosomy: One copy results in a cell (versus two).

Trisomy: Three copies (versus 2).

Mosaicism: Nondisjunction after conception, not all cells are affected.
How does down syndrome happen?
Trisomy 21. Extra chromosome 21.
Which defects are more lethal? Ones in smaller chromosomes or larger ones.
Larger ones (the ones with smaller numbers).
What is translocation?
Large segment from one chromosome breaks and reattaches to different chromosome during meiosis.
What is a karyotype?
Picture of arranged, paired chromosomes placed in order by size and matched by centromere location plus banding pattern.

Used to look for total numbers and whether chromosome pairs appear to be equal size and banding patterns.
What does polygenic mean?
Interaction of several genes at different loci on different chromosomes that determine phenotype.

Hard to predict outcome.

Examples: Height, weight, skin color, cardiovascular disease, type II diabetes.
What is a multifactorial disorder?
Polygenic PLUS environmental influences determines what gene is expressed.
What does genetic predisposition mean?
Environmental influences effect to what extent a gene is expressed.
What are some environmental influences that can effect genetic predisposition?
Chemicals (alcohol, tobacco, drugs, hromones).

Maternal and paternal age.

Nutrition

Viruses.

Altitude.
When do you usually see multifactorial diseases?
Later in life, hard to predict outcome.
What does epigenetic mean?
Above the genome.
What is epigenetic inheritance?
Consists of chemical compounds that reversibly modify the genome. Tells it what to do, where to do it, when to do it.

Does not change base sequence.

It alters gene expression and can be inherited.
Why is it important to manage genetic and developmental disorders?
1) important to determine so you can have a course of action

2) Prenatal screening for babies.
When is prenatal screening usually done?
Before or during pregnancy.

Done if parents are determined to be high risk
Age > 35
Signs (multiple spontaneous abortions
Medical history of disease.
What tests are usually done during prenatal screening? What are the risks of the screening?
Ultrasound (physical deformities).

Fetal Samples:
Amniocentes (fluid around fetus has DNA from baby).
Chorionic Villus (Take piece of placenta itself).

Maternal blood tests (baby enzymes and products in mom's blood.

Risks include accidental abortion or infection.
What do you get from genetic counseling?
Odds of having an affected child.

Implications of defect (what the defect is, what it does)

Prepare family for future

Other options (abortion or not).
Why is postnatal screening a state mandated test?
Early ID and treatment.
What is genetic screening?
Determine patterns in family history by using a pedigree to track disorders/diseases.
What is BRCA1 and BRCA2
Breast cancer/ovarian cancer.

Guys can get it to.
What is SNP testing?
Looking at thousands of bases across DNA which are known to vary.

These spots indicate risks.
What do future therapies using genetics want to do?
Understand molecular basis of genetic disease.

Diagnose genetic disease

Correct genetic disease.
What is recombinant DNA technology?
Genes from two different sources are combined into a single organism to produce new traits.
What is gene therapy?
Technique for correcting defective genes responsible for disease.
How does gene therapy work?
Direct delivery or carrier molecule called a vector used to deliver therapeutic gene to patient's target cells.

Newly inserted gene functions effectively within cell.
What is the most common vector in gene therapy?
A virus that is genetically altered to carry normal human DNA.
Is gene therapy safe?
Don't know, still experimental.
What are the limitations of gene therapy?
Short-lived nature of gene therapy

Problem with viral vectors (targeting correct cells)

Immune response (how to avoid them taking out vectors and new cells)

Multigene disorders (how do we target them?)
What is stem cell research?
Embryonic cells used to create new cells in the body.

Easily avoid organ rejection.
Why not use embryonic stem cells?
Controversy.
Why not use adult stem cells instead of embryonic?
It is limited, doesn't have as much potential as embryonic stem cells.