Class Notes (806,874)
United States (312,244)
BIOSC 0160 (63)
All (16)

The Cell Cyclye Notes

7 Pages
Unlock Document

University of Pittsburgh
Biological Sciences
BIOSC 0160

1/7 Chapter 11: The Mitotic Cell Cycle Cell Division • All new cells come from preexisting cells • One cell divides into two daughter cells that are genetically identical o Genome of the original cell is copied and distributed to both daughter cells o Cytoplasm is divided, including mitochondria, plastids, etc.  One exception is localized mRNA • Functions: o Reproduction (only in certain species)  Eukaryotic unicellular organisms (paramecium, yeast)  Asexual multicellular organisms (hydra) o Development  Cell division of zygote o Growth  Increases the size of structures o Tissue Maintenance/Repair  Functions in wound healing (adult stem cells are activated to replace the tissue that is lost) • Eukaryotes undergo mitosis and cytokinesis o Nuclear division occurs in mitosis, followed by cytoplasmic division • Prokaryotes undergo binary fission o Don’t contain nuclei, so no nuclear division Chromosomes and Chromatin • The Eukaryotic Chromosome o Linear (unlike bacteria, which have circular chromosomes) 1/7 o Complex of DNA and protein called chromatin o Bears genes o Found inside the nucleus  Genes are present in euchromatin (eu=true)  Undergoes condensation and relaxation o Also bears non-genic DNA (heterochromatin) o Chromosome number varies between species (humans have 46) • Chromatin o DNA-protein complex that makes up chromosomes o Functions:  DNA packing and chromosome condensation  Regulation of gene expression o Packing Hierarchy:  Sets up well for gene regulation  Most Basic Level • DNA wrapped around nucleosome like beads on a string • Nucleosomes have four histomes (H2A, H2B, H3, H4) • H1 attaches DNA  Next Level • H1 binds to next nucleosome, can cause 30 nm fiber to form • No linker DNA  Next Level 1/7 • Fiber becomes part of a large looped domain on a protein scaffold (super packed)  Next Level • Fully condensed, protein scaffold folds up • Karyotypes o Array of chromosomes that a person’s cells bear o OR a picture of that array  When fully condensed  Labeled from largest to smallest autosomes with sex chromosomes at the end The Cell Cycle • Interphase: cells grow and copy chromosomes • Mitotic (M) Phase: cells undergo mitosis/ cytokinesis • Interphase o G 1 Gap 1  Growth and production of cytoplasmic  organelles  Preparation for duplication (ready with  histones) o S: Synthesis  Replication of chromosomes  Centrosome (microtubule organizing  center) replication  Continues growth • Interphase cont. o G 2 Gap 2 1/7  Continued growth and preparation for mitosis  Two centrosomes with centrioles  Synthesizes tubulin • Mitosis o Prophase  Mitotic spindle (spindle apparatus) begins to form  Chromosomes condense o Prometaphase  Nuclear envelope fragments  Kinetochores form at centromeres  Microtubules attach to centromeres  Polar microtubules extend towards m
More Less

Related notes for BIOSC 0160

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.