Lecture 1.1 (Intro) Flashcards
Define diploid and haploid
Diploid = two copies
Haploid = one copy
1) Define aneuploid. When is this term usually used?
2) Define polyploid
1) Wrong number of copies; in relation to one chromosome in an individual
2) Too many copies of everything
1) What does soma mean?
2) Are somatic cells diploid, haploid, or both?
3) How many chromosomes do they have?
1) “Body” (thanks Greek)
2) All diploid (so two copies)
3) 46 chromosomes (2n)
1) What are gametes?
2) Are they haploid, diploid, or both?
3) How many chromosomes?
1) Eggs and sperm
2) These are haploid
3) 23 chromosomes (just n)
1) Define autosomes
2) Define sex chromosomes
1) Non-sex chromosomes
2) X and Y
1) Define karyotype
2) Define cytogenetics
1) A lab-made image of a complete set of chromosomes arranged in numerical order
2) Study of chromosomes
1) Define chromatin
2) What are histones?
1) Complex of DNA and histones that makes up a chromosome
2) DNA binding proteins that chromatin wraps around
1) What is “loosely wrapped” around histones? What is its unique characteristic?
2) What is “tightly wrapped” around histones? What is it inaccessible for?
1) Euchromatin; open in some places
2) Heterochromatin; inaccessible for transcription
1) _________________ is when DNA is code is written into RNA
2) Define Scribe
1) Transcription
2) Write (again, Greek)
1) _____________ is when the code is actually turned into protein
2) What does translation literally mean?
1) Translation (Like its changing languages all together!)
2) “carry across”
1) What is a codon?
2) How many amino acids are there?
3) How many possibilities do the number of amino acids result in?
1) The 3-nucleotide code for an amino acid
2) 20 amino acids
3) 4^3 possibilities
mRNA structure:
1) Of the 64 codons, _____ code for AA’s, 1 codes for “________” and _____ code for “stop”.
2) The _________ nucleotide in the sequence often has little bearing on which amino acid is coded
1) 60; start; 3
2) Third
DNA structure:
1) RNA polymerase binds at the _________________ and initiates transcription
2) Define exon
1) promoter region
2) DNA sequences that are transcribed into mRNA and translated into an amino acid sequence of a protein
DNA structure:
1) Define intron
2) Define terminator region
1) DNA sequences that are transcribed, but are spliced out of the pre-mRNA (¬ included in the mRNA)
2) DNA sequence that signals the end of transcription
DNA/mRNA structure:
1) Define cap. What is it attached to and when?
2) Define splicing
1) A modified base (guanine nucleotide) attached to the 5’ end of eukaryotic mRNA molecules during RNA processing
2) Introns are spliced out to produce mature mRNA
DNA/ mRNA structure:
1) Define Poly-A tail
2) What is it added to and when?
1) A string of 30-100 adenine (A) nucleotides
2) 3’end of mRNA molecules during RNA processing
1) What happens to mRNA after processing and splicing?
2) What occurs at the cytoplasm?
1) Transported from the nucleus to the cytoplasm
2) The encoded information is translated into the amino acid sequence of a protein
1) Translation requires the interaction of what 6 things?
2) What are ribosomes? What occurs here?
3) What are tRNA molecules?
1) mRNA, ribosomes (rRNA), tRNA molecules, amino acids, enzymes, & energy sources
2) Ribosomes are the tanks that roll over mRNA on which protein synthesis occurs (composed of two subunits of rRNA combined with proteins)
3) Adapters that recognize amino acids in the nucleotide sequence in mRNA, the gene transcript
1) Define amino group
2) Define carboxyl group
3) Define R group
4) Are R groups positively charged, negatively charged, or neutral?
1) A chemical group (NH2) found in all amino acids and at one end of a polypeptide chain
2) A chemical group (COOH) found in all amino acids and at one end of a polypeptide chain
3) A side chain unique to each amino acid [each AA has one]
4) Can be positively charged, negatively charged, or neutral
slide 20
Do this enough times and you have a polypeptide, or protein
After polypeptides leave the ribosome, they are __________-ed, _____________-ed, and _______________-ed
folded, modified, and transported
1) Polypeptides fold into a ___________-dimensional shape, often assisted by other proteins, called _______________.
2) True or false: polypeptides can be chemically modified in many different ways, producing functionally different proteins from one polypeptide
3) When can a polypeptide be called a protein?
1) three; chaperones
2) True
3) After it has been folded, modified, and becomes functional
1) True or false: Genes are concentrated in one part of the chromosomes
2) Are some regions gene rich or poor, or is it always consistent?
3) There are __________________ base pairs in the human genome
1) False; genes are scattered all over the chromosomes
2) Some regions (even whole chromosomes) are gene rich or gene poor
3) 3 billion
1) What percent of the genome actually codes for genes?
2) Is the rest “just noise”?
1) 5%
2) A lot of this material isn’t just noise; it’s partially responsible for gene regulation
True or false: About half of the material in our DNA only happens once.
Explain your answer
True; “Single-Copy DNA sequence”
-Genes are here
1) The half of the material in our DNA that happens more than once has distinct classes of what?
2) What are these called?
1) “repetitive DNA sequences”
2) Alu family and LINE segments
1) Define Epi (in epigenetics)
2) Why is it called this?
3) What do epigenetics have an effect on?
1) On top or above
2) “above” the code – DOES NOT CHANGE DNA CODE
3) Which genes are transcribed and when
What are the 3 main routes of epigenetics?
1) DNA methylation
2) Histone modifications
3) Histone variants
1) Define genetic imprinting
2) Give an example of this
3) What does this process do in addition to “turning off” or “silencing” a gene?
1) The parental “tagging” of alleles that prevent transcription
2) Methylation
3) Caries info abt which parent imprinted the gene
A replicated chromosome contains what?
Two sister chromatids connected by a centromere
List the 3 phases of interphase and 4 phases of mitosis
1) Interphase: G1, S, G2
2) Mitosis: Prophase, metaphase, anaphase, telophase
List each phase of interphase, and describe the middle phase
1) G1
2) S(ynthesis): DNA is replicated, and chromosomes form sister chromatids
3) G2
List each phase of mitosis and describe the two middle phases
1) Prophase
2) Metaphase: chromosomes line up on midline of cell
3) Anaphase: chromosomes begin to separate
4) Telophase
Describe cytokinesis
Cleavage furrow forms and deepens, cytoplasm divides
List 4 types of chromosomes
1) Metacentric
2) Submetacentric
3) Acrocentric
4) Telocentric
In Cytokinesis in mitosis and meiosis, are the two cells separating are genetically identical?
In mitosis, the two cells separating are genetically identical. In meiosis they are not.
What separate during anaphase?
Paired homologous chromosomes
List the 4 types of protein structures
1) Primary (strand)
2) Secondary (alpha helix)
3) Tertiary (bundle)
4) Quaternary (a bunch of bundles)
Where are most of the genes located?
The single-copy DNA sequence half of the genome
Meiosis results in two kinds of haploid, sexual gametes; what are they?
1) Males produce spermatids by the process of spermatogenesis
2) Females produce oocytes by the process of oogenesis
In spermatogenesis:
1) One spermatogonium (2n) in the testis divides by mitosis to produce what two things?
2) What does one of those then divide into?
1) One spermatogonium and one primary spermatocyte
2) One primary spermatocyte (2n) divides by meiosis I to form to two secondary spermatocytes (n)
Spermatogenesis:
1) Two _____________________ (n) divide by meiosis II to form four _________________(n).
2) These four things undergo structural changes to become what?
3) What are the end products of spermatogenesis (meiosis I and II)?
1) secondary spermatocytes; spermatids
2) Functional spermatozoa (sperm)
3) Four functional gametes: spermatozoa
1) What is the first cell of oogenesis and what does it divide into?
2) When is development arrested?
1) One oogonium (2n) in the ovary divides by mitosis to produce one oogonium and one primary oocyte
2) The primary oocyte undergoes prophase I and then waits until puberty
Oogenesis:
1) When menses begins, what finishes dividing? What does it form?
2) What is the last step of oogenesis? What are the end products?
1) One primary oocyte (2n) in the ovary finishes dividing by meiosis I to form one secondary oocyte (n) and one polar body
2) One secondary oocyte (n) divides by meiosis II to form one ovum (n) and one more polar body
In oogenesis, the division of the cytoplasm in meiosis I and II is unequal, so in the end we have how many gametes and polar bodies?
One functional gamete (ovum or egg) & 2 Polar bodies
Oogenesis:
1) The primary oocyte undergoes ______________ and then waits until puberty
2) Where are homologues condensed and separated?
1) prophase I
2) Prophase I
1) Describe the mitochondrial chromosome’s size and shape.
2) The mitochondrial chromosome is only ___________ nucleotides in length and encodes just ______ genes.
1) A small circular molecule
2) 16,569; 37
1) Human cells have how many mitochondria? What does each contain?
2) Are mitochondrial genes are inherited exclusively maternally, paternally, or from both?
1) Hundreds to thousands of mitochondria; many copies of the mitochondrial chromosome
2) Exclusively maternally
1) Define allele
2) What can it describe the variance of? What does this suggest?
1) One of the alternative versions of a gene or DNA sequence at a given locus
2) The variance that exists in a single gene; points to the extant variation in an individual
Define polymorphism
An occurrence of mutation at least as common as 1%
1) What causes chromosome disorders/ defects?
2) True or false: chromosome disorders are uncommon
3) Chromosome disorders occur in about ________ out of every 1000 liveborn infants
4) Chromosome disorders are responsible for about _______ of all spontaneous 1st trimester abortions
1) An excess or a deficiency of the genes contained in whole chromosomes or chromosome segments
2) False; they’re common
3) 7
4) 1/2
1) What causes single-gene disorders?
2) Where may this be located? (3 places)
1) Mutations in individual genes
2) Mutant gene may be on an autosome, a sex chromosome, or in the mitochondrial genome
1) Are single-gene disorders common? What is the frequency out of 1000?
2) Do they account for a significant proportion of disease and death? Explain.
1) They are rare: ~1 in 1000 is the highest but the freq. is usually much lower
2) Yes, although individually rare, they account for a significant proportion of disease and death
1) Single-gene disorders affect what percent of the population sometime during their life?
2) Incidence of serious [single-gene] disorders in the pediatric population is about ________%; among hospitalized children about _____-_____%
1) 2%
2) 0.36%; 6-8%
1) What is responsible for the majority of diseases?
2) What kinds of disorders does this include?
1) Multifactorial inheritance
2) Prenatal developmental disorders, as well as many common disorders in adult life
1) How does multifactorial inheritance cause disease?
2) Incidence of multifactorial diseases is about ____% in the pediatric population and about ____% in the entire population
1) Multiple different genes act together, often in concert with environmental factors
2) 5%; 60%
1) When does spermatogenesis begin?
2) What about oogenesis?
1) Puberty
2) Embryogenesis
List 6 clinical indications for chromosome and genome analysis
1) Problems of early growth and development
-Malformations, short stature, ambiguous genitalia, intellectual disability
2) Still birth and neonatal death
3) Fertility problems
4) Family history
5) Neoplasia
6) Pregnancy (over 35)
What are the 4 reasons for genetic consultation?
1) Diagnoses or rules out a genetic condition
2) Arranges medical management
3) Communicates risks
4) Arranges psychosocial support
