Exam 4 : Classical Genetics I Flashcards
(32 cards)
What is a genome?
All of the genetic hereditary material in an organism
What is a genome made of?
All cells have genomes made from DNA molecules (chromosomes). Viruses can have DNA or RNA genomes
Describe the bacterial genome
single circular DNA chromosome (DNA molecule)
How do bacteria reproduce?
Binary fission
What is binary fission?
One cell divides into two cells of equal size.
Distinguish between a chromosome and chromatin.
A chromosome is a DNA molecule, a chromatin is the relaxed from of that DNA molecule
Where are chromosome located in eukaryotic cells?
in the nucleus
What is the chromosome made of?
DNA
What is a centromere?
a protein complex attached to a chromosome, often seen as a pinch point. it is a complex that can bind two chromosomes together.
What is the centromere’s role?
can hold sister chromatids together.
what are sister chromatids and how do they arise?
when chromosomes are replicated (in S phase) they form a second DNA molecule that is identical to itself. It’s still a single chromosome, but made up of two sister chromatids.
Distinguish between somatic cells and germ(gamete) cells.
somatic cells are cells of the body and are diploid (two copies of each chromosome). The gametes are sperm and egg, these are haploid cells with only one copy of each chromosome
Describe the cell cycle. What are the different phases?
The cell cycle consists of two main phases: Interphase and M phase. Interphase consists of G1, S, G2 phases. M phase consists of mitosis/meiosis and cytokinesis. The cell cycle is the life cycle of a cell.
What occurs during S phase?
S phases involves synthesis, chromosomes are duplicated. Centrosomes are also duplicated.
What is interphase?
interphase is every part of the cell cycle except for M phase (mitosis/meiosis,cytokinesis). it consists of 2 gap phases and synthesis phase
How is the cell cycle controlled?
Intracellular signals. Build up of a certain protein signal cell to move to another phases.
Describe mitosis.
a type of cellular reproduction where ploidy number stays the same . one diploid cell becomes two diploid cells
What are the phases of mitosis?
prophase, metaphase, anaphase, telophase, cytokinesis
What occurs in prophase?
nuclear envelope disintegrates, chromatin is packages into condensed chromosomes, centrosomes move to opposite poles of the cell, mitotic spindle go between them
What occurs in metaphase?
condensed chromosomes attach to spindle fibers by kinetochore complexes and line up on the imaginary metaphase plate, with a sister chromatid on opposite sides.
What occurs in anaphase?
sister chromatids are pulled apart to opposite poles of the cell
What occurs in telophase?
nuclei reform, spindle disappears, and condensed chromosomes relax back to chromatin
Cytokinesis
cytokinesis is cell division
How does cell division differ in plant vs. animal cells?
animal cells use actin fibers to cut cell in half. plant cells make a cell wall in the middle of the parent cell.
