Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Mendelian Genetics

A

Gregor Mendel

Laws that describe family patterns of inheritance of single genes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cytogenetics

A

Uses techniques of cytology and microscopy to study chromosomes and their relationships to hereditary traits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Molecular Genetics

A

Studying structure and function of DNA at the molecular level.
How genes control cellular functions, development, and disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Genomic Medicine

A

Application of knowledge of the human genome for prediction, diagnosis, and treatment of genetic diseases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

DNA

A

Each cell:
46 human chromosomes
2m of DNA
3 billion DNA subunits (the bases: A, T, C, G)
20,000-25,000 genes code for proteins that perform all life functions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

DNA Molecular Structure

A

A kind threadlike molecule with a uniform diameter but varied.
2 meters in length.
A polymer that encodes hereditary information; 4 different repeating monomers(nucleotides) make up DNA polymer.
Each nucleotide consists of one sugar(deoxyribose), one phosphate group, one nitrogenous base:either pyrimidine (single carbon-nitrogen ring) or purine (double ring); A, T, C, G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Nitrogen bases

A

Purines:double ring(adenine,guanine)
Pyrimidines:single ring(cytosine,thymine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

DNA Structure

A

Molecular shape is a double helix(staircase)
Each side piece is a backbone composed of phosphate groups alternating with the sugar deoxyribose.
Steplike connections between backbones are pairs of nitrogen bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Complimentary Base Pairing

A

Nitrogenous bases united by hydrogen Bonds. Purine on one backbone always base pairs with a pyrimidine on the other.
A-T two hydrogen bonds
C-G three hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Law of Complimentary Base Pairing

A

One strand determines base sequence of other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DNA Function

A

Genes-genetic instructions for synthesis of proteins.
Gene-segment of DNA that tells how to make a certain protein(codes for protein)
Genome-all the genes of one person
-humans have estimated 25,000 to 35,000 genes.
-2% of total DNA
-Other 98% in noncoding DNA; plays role in chromosomes structure, very important regulation of gene activity, same has no function at all-junk DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Chromatin

A

In the nucleus, DNA is complexed with protein to form threadlike Chromatin:

  • nondividing state and the DNA molecules are highly compacted.
  • coiled around core histone proteins to form nucleosides.
  • zig-zagged, looped and coiled into itself.
  • functions to package DNA into small volumes to fit the cell.
  • chromatin condense to chromosomes during mitosis(higher order DNA Organization)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Flow of Genetic Information

A

Replication(DNA-DNA)
Transcription(DNA-RNA)
-in nucleus DNA is transcribed or copied into a messenger RNA(mRNA) molecule
Translation(RNA-Proteins)
-in the cytoplasm, the mRNA code is translated into amino acids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Production of Amino Acids

A
  1. DNA double helix
  2. seven base triplets from DNA; 3 base pairs in gene code for one amino acid.
  3. the corresponding codons of mRNA transcribed from the DNA triplets
  4. the anticodons of tRNA that bind to the mRNA codons
  5. the amino acids are carried by those 6 tRNA molecules
  6. the amino acids linked into a peptide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Human Genome

A

Humans have 46 chromosomes
-23 from mom and 23 from from dad
Genome-all the DNA in one 23-chromosomes set
An organisms complete set of genetic instructions
-3.1 billion nucleotide pairs in human genome
Every cell in our body has the same DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Gene Regulation

A

What makes one cell type different from another.
Genes are turned on and off from day to day
Their products are needed or not
Many genes are permanently turned off in any given cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gene

A

Body had 20,000 genes.
Not a separate gene for every protein.
A gene is a segment of DNA that tells the cell how to make a certain protein (codes for protein)
Amino acid sequence is determined by the nucleotide sequence in DNA.
A Information containing segment of DNA that codes for the production of a molecule of RNA that plays a role in synthesizing one or more products.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The Human Genome Project(1990-2003)

A

International effort to decipher the blueprint of a human being.
Hundreds of scientists at 20 sequencing centers in China , France, Germany, Great Britain, Japan, and United States collaborated to discover the complete set of human genes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Findings of Human Genome Project

A

Homosapiens have only about 20,000 genes;not the 100,000 formerly believed
Genes generate millions of different proteins; single gene can code for many different proteins
Genes average about 3,000 bases long; range up to 2.4 million bases
All humans are at least 99.9% genetically identical; 0.01% variation that we can differ from one another in more than 3 million base pairs called single nucleotide polymorphisms(SNP);various combinations of these single nucleotide polymorphisms account for all human variation
Some chromosomes are gene rich and some are gene poor
We now know the location of many disease producing mutations; opens the door for a new branch of medical diagnosis and treatment called Genomic Medicine; we previously only knew fewer than 100 locations

20
Q

Errors and Mutations

A

Error rates of DNA polymerase

  • likely about 60 errors occur with each new generation; you have 60 different DNA bases you did not inherit from either parents
  • Mutations are changes in DNA structure due to replication error of environmental factors
  • some cause no effect; some kill cell; turn it cancerous; or cause genetic defects in future generations
21
Q

Heredity

A

Transmission of genetic characteristics from parent to offspring.
Karyotype-chart of 46 chromosomes laid out in order by size and other physical features
23 pairs of chromosomes,the 2 members of each pair are called homologous chromosomes
-22 pairs called autosomes(look alike and carry the same genes)
-1pair of sex chromosomes (x and y; female have xx and male have xy)
Diploid-any cell with 23 pairs of chromosomes
Haploid-contain half as many chromosomes as somatic cells; only sperm and egg cells are haploid (germ cells)

22
Q

Locus

A

The location of a particular gene on a chromosome

23
Q

Alleles

A

Different forms of same gene on 2 homologous chromosomes

24
Q

Dominant Allele

A

Represented by capitol letter. Corresponding trait is usually detectable in the individual. Masks the effect of any recessive allele that may be present. Produces protein responsible for visible trait.

25
Q

Recessive Allele

A

Expressed only when present on both of the homologous chromosomes (inherited from Mom and Dad) or no dominant alleles at that locus

26
Q

Genotype

A

The alleles that an individual possesses for a particular trait; homozygous alleles are 2 identical alleles for a trait, heterozygous alleles are different alleles for that gene.

27
Q

Phenotype

A

An observable trait of a genotype. An allele is expressed if it shows in the phenotype of an individual.

28
Q

Genetic Counselors

A

Perform genetic testing or refer clients for tests, advise couples on the probability of transmitting genetic diseases, and assist people on coping with genetic disease.

29
Q

Punnett Square

A

Graphical method showing all possible combinations of offspring genotypes. Ex:shows how heterozygous carriers of hereditary diseases such as cystic fibrosis can have an affected offspring

30
Q

Monohybrid crosses

A

Cross that involved one pair of contrasting traits. Solve using Punnett Square. Sample problems:

  • Rr x rr
  • RR x rr
  • Rr x Rr
  • Rr x RR
31
Q

Gene Pool

A

Collective genetic makeup of population.

32
Q

Multiple Alleles

A

More than 2 alleles for a trait.

33
Q

Codominant

A

Both alleles expressed such as AB blood type.

34
Q

Incomplete Dominance

A

Phenotype intermediate between traits for each allele

35
Q

Polygenic Inheritance

A

2 or more loci to a single phenotypic trait(skin and eye color, height, cholesterol levels, and heart disease)

36
Q

Pleitropy

A

One gene produces multiple phenotypic effects. Ex:darkened sclera of eye

37
Q

Sex Linkage

A

Sex-linked traits- carried on the x and Y chromosomes and therefore tend to be inherited by one sex more than the other.
Recessive color blindness allele on x, no gene locus for trait on y, so red green color blindness more common on men( mother is carrier)

38
Q

Penetrance

A

The percentage of a population with a given genotype that actually exhibits the predicted phenotype.

39
Q

Role of Environment

A

Environmental factors play an important role in the expression of all genes; all gene expression depends on nutrition; brown eye color requires phenylalanine from diet to produce melanin pigment; need both the genetic recipe(genotype) and the ingredients (phenotype).

40
Q

Dominant and Recessive Alleles at the Population Level

A
  • common misconception that dominant alleles must be more common in the gene pool than recessive alleles
  • some recessive alleles, blood type O, are the most common
  • some dominant alleles, polydactyl and blood type AB, are rare in the population
41
Q

Cancer

A

Uncontrolled division of cells in a part of the body.
Genetic disease.
Carcinogens environmental cancer-causing agents.
Can trigger new gene
-mutations; carcinogens, radiation, ultraviolet rays, x-rays;
-chemical; cigarette tar, food preservatives, industrial chemicals
-viruses; human papilloma virus, hepatitis C, and type 2 herpes simplex
5-10% of cancers are hereditary

42
Q

Benign Tumors

A

Slow growth, contained in fibrous capsule

Will not metastasize, usually easy to treat

43
Q

Malignant Tumor

A

Fast growing

Metastasize-give off cells that sees the growth of multiple tumors elsewhere

44
Q

Oncology

A

Medical specialty that deals with both benign and malignant tumors.

45
Q

Cancer Names

A

Named for the tissue of origin

  • carcinomas:epithelial tissue
  • lymphomas:lymph nodes
  • melanomas:pigment cells of epidermis (melanocytes)
  • leukemias:blood forming tissues
  • sarcomas:in bone, other connective tissue or muscle
46
Q

Chromosome

A

Threadlike structure found in the nucleic acid of a cell that carries all the genetic information. 46 in humans.

47
Q

Central Dogma

A

DNA to messenger RNA (mRNA) to proteins. Flow of genetic information.