Lecture 1 Genetics Flashcards
Q: What are the four main ABO blood types?
A: A, B, AB, and O.
Why are homologous chromosomes not identical?
They carry different alleles and may have undergone crossing over.
What happens during the G1 phase of the cell cycle?
Cell grows and prepares for DNA replication.
What is a human karyotype used for?
Identifying chromosomal abnormalities, like trisomy 21.
What is the difference between euchromatin and heterochromatin?
Euchromatin is less condensed and transcriptionally active, while heterochromatin is more condensed and generally inactive.
What is the outcome of Meiosis I?
A: Two haploid cells, with each chromosome consisting of two sister chromatids
How is Meiosis II similar to mitosis?
Both involve the separation of sister chromatids.
What is the main difference between meiosis and mitosis in terms of chromosome number?
Meiosis halves the chromosome number (diploid to haploid), while mitosis maintains it.
What is the study of Genetics?
The study of the inheritance of observable traits from one generation to the next and their effect on populations and species.
Do environmental factors influence ABO blood groups?
No, ABO blood groups show no variation due to environmental factors.
Can the expression of a gene be affected by the environment?
Yes, examples include the effect of temperature on fruit fly wing size and rabbit fur color
What is the difference between genotype and phenotype?
A: Genotype refers to an organism’s genetic makeup, while phenotype refers to an organism’s physical and biochemical traits.
At which chromatin structure level does DNA become transcriptionally inactive?
At the level of the 30 nm chromatin fiber and beyond
What is the main purpose of mitosis?
To ensure that an exact copy of the parent cell’s DNA is passed on to the two new daughter cells
What is the purpose of meiosis?
To reduce the diploid complement of chromosomes to a haploid complement, producing sex cells (gametes) for sexual reproduction
DNA is a ? Stranded
Composed of complementary ? Bases
Joined by ? Bonds
And a ? Backbone
Double stranded molecule
Nitrogenous bases
Joined by Hydrogen bonds
And a deoxyribose + phosphate backbone
Homologous Chromsomes describe them.
Same size same shape same structure same length same genes BUT different alleles.
Are Sex chromosomes Homolgous and why ?
X/Y are an exception to the Homologous Chromosomes Rule i.e. dont have same length size shape structure or gene but are still considered homologous.
What is a karyotype ?
A karyotype is a preparation of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, sorted by length, centromere location and other features.
?+?=Chromatin ?
DNA+Histones = Chromatin
Rank
Nucleosomes (beads)
30 nm chromatin fiber
Chromatin loops
Sister chromatids
Metaphase chromsome
Nucleosomes
30Nm chromatin fiber
Chromatin loops
Sister chromatids
Metaphase chromsomes
Is Genetic material already duplicated at the start of mitosis ?
Yes. It is
Does Mitosis include interphase ? What happens during interphase ?
No Mitosis does not include Interphase.
G1- first stage after cell divided.
Cell grows in size and synthesizes mRNA
S- phase -> DNA replication (Chromosomes duplicated , end goal : each chromosome with 2 sister chromatids connected at centromere).
A
G2 -> Check for any damages and prepares for Mitosis and Cytokinesis.
What mitotic stage does chromatin start to become distinct chromosomes ?
Prophase
