Chapter 10 - PowerPoint Flashcards
What are the two types of nuclear division?
mitosis and meiosis
In mitosis are the daughter cells exact genetic copies of the parent cells?
yes
What are ploidy human cells?
diploid
What does diploid mean?
2 copies of each chromosomes, 2n
In meiosis how many divisions are there?
2
How many daughter cells are produced in meiosis?
4
What are the daughter cells of meiosis called?
gametes
What is haploid mean?
one copy, n
What is the master program of molecular checks and balences?
In mitosis, DNA is replicated and split evenly
What is the mitotic cytoskeleton do?
separates replicated DNA molecules precisely into the daughter cells
What are chromosomes made of?
DNA and proteins
What do proteins do in DNA?
stabilize, assist in packaging DNA during cell division, and influence the expression of individual genes
What shape are chromosomes in eukaryotes?
linear
What does histone proteins do?
compact DNA
What is chromatin?
DNA and all of its associated protiens
What is a nucleosome?
8-protein nucleosome core particle forms when DNA winds around the histones H2A, H2B, H3, and H4
What connects nucleosomes?
shorter liner segment of DNA
What are the histone proteins?
H2A, H2B, H3, and H4
How many of each histone proteins are in a nucleosome?
2
What is the first step of compaction
formation of nucleosomes
What charges does DNA have? why?
negative bc of phosphate groups
How wide is a nucleosomes?
10nm
How are nucleosomes further compacted? how big is it?
nucleosome and linker are bound by the fifth histone protein H1
30 nm
What is the difference between chromosomes and chromatin?
chromosomes are final form, everything else before this with proteins is chromatin
What does the solenoid model predict?
nucleosomes spiral helically
with about six nucleosomes per turn
Which chromatin is packed loosley?
euchromatin
Which chromatin is packed densly?
heterochromatin
Is euchromatin or heterochromatin regions more highly expressed?
euchromatin
What are Sister Chromatids
2 copies of the chromosome within the replicated chromosome
What are the sister chromatids held together by? where?
sister chromatid cohesion, at the center
What is cohesion
protein complex
Are homologous chromosomes identical?
nope
Are sister chromatids identical?
yes
What is ploidy?
The number of chromosome sets in a cell or species
What is a Karyotype?
Individual’s particular array of chromosomes.
How to prepare cells for a karyotypes?
- Add sample to culture medium that has stimulator for growth and division of cells (white blood cells in the case of blood). Incubate at 37oC.
- Stain the cells so that the chromosomes are distinguished.
- View the stained cells under a microscope equipped with a digital imaging
system and take a digital photograph.
What are the steps included in eukaryotic cell cycle?
G1, S, G2, M, C
What is the longest phase?
G1
What steps are in interphase?
G1, S, G2
What is G1?
Gap 1 Phase, where primary growth takes places, is the longest phase
Which is phase varies in length?
G1
What is a cell that stays in the G0 phase?
neuron
How long does it take for a cell to divide?
24 hrs
how long does the G1 phase take?
10 hrs
How long does the S phase take?
9 hrs
How long does the G2 phase take?
4 hrs
How long does the M phase take?
1 hr
What happens in the S (synthesis) phase?
replication of DNA
What happens in the G2 phase?
organelles replicate, microtubules organize
What are the 5 phases of mitosis?
prophase, prometaphase, metaphase, anaphase, telophase
What happens in cytokinesis?
separation of 2 new cells
Are human sex cells haploid or diploid?
haploid
What happens to the centrioles during mitosis?
they duplicate and divide
What is the main microtubule organizing center (MTOC)?
centrosome
Where do microtubules extend from?
centrosomes
What are asters?
starlike arrays formed from microtubules extending from the centersome
What happens to the nuclear envelope during interphase?
breaks down
In mitosis, at what stage do chromosomes first become visible with a light microscope?
prophase
Do asters exist in both plants and animal?
no, just animals