Lecture 1.1 (Intro)

Question 1

Define diploid and haploid

Answer 1

Diploid = two copies
Haploid = one copy

Question 2

1) Define aneuploid. When is this term usually used?
2) Define polyploid

Answer 2

1) Wrong number of copies; in relation to one chromosome in an individual
2) Too many copies of everything

Question 3

1) What does soma mean?
2) Are somatic cells diploid, haploid, or both?
3) How many chromosomes do they have?

Answer 3

1) “Body” (thanks Greek)
2) All diploid (so two copies)
3) 46 chromosomes (2n)

Question 4

1) What are gametes?
2) Are they haploid, diploid, or both?
3) How many chromosomes?

Answer 4

1) Eggs and sperm
2) These are haploid
3) 23 chromosomes (just n)

Question 5

1) Define autosomes
2) Define sex chromosomes

Answer 5

1) Non-sex chromosomes
2) X and Y

Question 6

1) Define karyotype
2) Define cytogenetics

Answer 6

1) A lab-made image of a complete set of chromosomes arranged in numerical order
2) Study of chromosomes

Question 7

1) Define chromatin
2) What are histones?

Answer 7

1) Complex of DNA and histones that makes up a chromosome
2) DNA binding proteins that chromatin wraps around

Question 8

1) What is “loosely wrapped” around histones? What is its unique characteristic?
2) What is “tightly wrapped” around histones? What is it inaccessible for?

Answer 8

1) Euchromatin; open in some places
2) Heterochromatin; inaccessible for transcription

Question 9

1) _________________ is when DNA is code is written into RNA
2) Define Scribe

Answer 9

1) Transcription
2) Write (again, Greek)

Question 10

1) _____________ is when the code is actually turned into protein
2) What does translation literally mean?

Answer 10

1) Translation (Like its changing languages all together!)
2) “carry across”

Question 11

1) What is a codon?
2) How many amino acids are there?
3) How many possibilities do the number of amino acids result in?

Answer 11

1) The 3-nucleotide code for an amino acid
2) 20 amino acids
3) 4^3 possibilities

Question 12

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

Answer 12

1) 60; start; 3
2) Third

Question 13

DNA structure:
1) RNA polymerase binds at the _________________ and initiates transcription
2) Define exon

Answer 13

1) promoter region
2) DNA sequences that are transcribed into mRNA and translated into an amino acid sequence of a protein

Question 14

DNA structure:
1) Define intron
2) Define terminator region

Answer 14

1) DNA sequences that are transcribed, but are spliced out of the pre-mRNA (&not included in the mRNA)
2) DNA sequence that signals the end of transcription

Question 15

DNA/mRNA structure:
1) Define cap. What is it attached to and when?
2) Define splicing

Answer 15

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

Question 16

DNA/ mRNA structure:
1) Define Poly-A tail
2) What is it added to and when?

Answer 16

1) A string of 30-100 adenine (A) nucleotides
2) 3’end of mRNA molecules during RNA processing

Question 17

1) What happens to mRNA after processing and splicing?
2) What occurs at the cytoplasm?

Answer 17

1) Transported from the nucleus to the cytoplasm
2) The encoded information is translated into the amino acid sequence of a protein

Question 18

1) Translation requires the interaction of what 6 things?
2) What are ribosomes? What occurs here?
3) What are tRNA molecules?

Answer 18

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

Question 19

1) Define amino group
2) Define carboxyl group
3) Define R group
4) Are R groups positively charged, negatively charged, or neutral?

Answer 19

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

Question 20

slide 20

Answer 20

Do this enough times and you have a polypeptide, or protein

Question 21

After polypeptides leave the ribosome, they are __________-ed, _____________-ed, and _______________-ed

Answer 21

folded, modified, and transported

Question 22

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?

Answer 22

1) three; chaperones
2) True
3) After it has been folded, modified, and becomes functional

Question 23

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

Answer 23

1) False; genes are scattered all over the chromosomes
2) Some regions (even whole chromosomes) are gene rich or gene poor
3) 3 billion

Question 24

1) What percent of the genome actually codes for genes?
2) Is the rest “just noise”?

Answer 24

1) 5%
2) A lot of this material isn’t just noise; it’s partially responsible for gene regulation

Question 25

True or false: About half of the material in our DNA only happens once.
Explain your answer

Answer 25

True; “Single-Copy DNA sequence”
-Genes are here

Question 26

1) The half of the material in our DNA that happens more than once has distinct classes of what?
2) What are these called?

Answer 26

1) “repetitive DNA sequences”
2) Alu family and LINE segments

Question 27

1) Define Epi (in epigenetics)
2) Why is it called this?
3) What do epigenetics have an effect on?

Answer 27

1) On top or above
2) “above” the code – DOES NOT CHANGE DNA CODE
3) Which genes are transcribed and when

Question 28

What are the 3 main routes of epigenetics?

Answer 28

1) DNA methylation
2) Histone modifications
3) Histone variants

Question 29

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?

Answer 29

1) The parental “tagging” of alleles that prevent transcription
2) Methylation
3) Caries info abt which parent imprinted the gene

Question 30

A replicated chromosome contains what?

Answer 30

Two sister chromatids connected by a centromere

Question 31

List the 3 phases of interphase and 4 phases of mitosis

Answer 31

1) Interphase: G1, S, G2
2) Mitosis: Prophase, metaphase, anaphase, telophase

Question 32

List each phase of interphase, and describe the middle phase

Answer 32

1) G1
2) S(ynthesis): DNA is replicated, and chromosomes form sister chromatids
3) G2

Question 33

List each phase of mitosis and describe the two middle phases

Answer 33

1) Prophase
2) Metaphase: chromosomes line up on midline of cell
3) Anaphase: chromosomes begin to separate
4) Telophase

Question 34

Describe cytokinesis

Answer 34

Cleavage furrow forms and deepens, cytoplasm divides

Question 35

List 4 types of chromosomes

Answer 35

1) Metacentric
2) Submetacentric
3) Acrocentric
4) Telocentric

Question 36

In Cytokinesis in mitosis and meiosis, are the two cells separating are genetically identical?

Answer 36

In mitosis, the two cells separating are genetically identical. In meiosis they are not.

Question 37

What separate during anaphase?

Answer 37

Paired homologous chromosomes

Question 38

List the 4 types of protein structures

Answer 38

1) Primary (strand)
2) Secondary (alpha helix)
3) Tertiary (bundle)
4) Quaternary (a bunch of bundles)

Question 39

Where are most of the genes located?

Answer 39

The single-copy DNA sequence half of the genome

Question 40

Meiosis results in two kinds of haploid, sexual gametes; what are they?

Answer 40

1) Males produce spermatids by the process of spermatogenesis
2) Females produce oocytes by the process of oogenesis

Question 41

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?

Answer 41

1) One spermatogonium and one primary spermatocyte
2) One primary spermatocyte (2n) divides by meiosis I to form to two secondary spermatocytes (n)

Question 42

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)?

Answer 42

1) secondary spermatocytes; spermatids
2) Functional spermatozoa (sperm)
3) Four functional gametes: spermatozoa

Question 43

1) What is the first cell of oogenesis and what does it divide into?
2) When is development arrested?

Answer 43

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

Question 44

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?

Answer 44

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

Question 45

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?

Answer 45

One functional gamete (ovum or egg) & 2 Polar bodies

Question 46

Oogenesis:
1) The primary oocyte undergoes ______________ and then waits until puberty
2) Where are homologues condensed and separated?

Answer 46

1) prophase I
2) Prophase I

Question 47

1) Describe the mitochondrial chromosome’s size and shape.
2) The mitochondrial chromosome is only ___________ nucleotides in length and encodes just ______ genes.

Answer 47

1) A small circular molecule
2) 16,569; 37

Question 48

1) Human cells have how many mitochondria? What does each contain?
2) Are mitochondrial genes are inherited exclusively maternally, paternally, or from both?

Answer 48

1) Hundreds to thousands of mitochondria; many copies of the mitochondrial chromosome
2) Exclusively maternally

Question 49

1) Define allele
2) What can it describe the variance of? What does this suggest?

Answer 49

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

Question 50

Define polymorphism

Answer 50

An occurrence of mutation at least as common as 1%

Question 51

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

Answer 51

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

Question 52

1) What causes single-gene disorders?
2) Where may this be located? (3 places)

Answer 52

1) Mutations in individual genes
2) Mutant gene may be on an autosome, a sex chromosome, or in the mitochondrial genome

Question 53

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.

Answer 53

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

Question 54

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 _____-_____%

Answer 54

1) 2%
2) 0.36%; 6-8%

Question 55

1) What is responsible for the majority of diseases?
2) What kinds of disorders does this include?

Answer 55

1) Multifactorial inheritance
2) Prenatal developmental disorders, as well as many common disorders in adult life

Question 56

1) How does multifactorial inheritance cause disease?
2) Incidence of multifactorial diseases is about ____% in the pediatric population and about ____% in the entire population

Answer 56

1) Multiple different genes act together, often in concert with environmental factors
2) 5%; 60%

Question 57

1) When does spermatogenesis begin?
2) What about oogenesis?

Answer 57

1) Puberty
2) Embryogenesis

Question 58

List 6 clinical indications for chromosome and genome analysis

Answer 58

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)

Question 59

What are the 4 reasons for genetic consultation?

Answer 59

1) Diagnoses or rules out a genetic condition
2) Arranges medical management
3) Communicates risks
4) Arranges psychosocial support