Foundations of Biology Exam 3: The Cell Cycle

the third rule of cell theory

all cells arise from pre-existing cells

binary fission

cell division that creates an entirely new organism; done by prokaryotes and single cell eukaryotes

development

a reason multicellular organisms undergo mitotic cell division, from a single cell into a multicellular organism

cell replacement

a reason multicellular organisms undergo mitotic cell division, many cells have short lifespans and need to be replaced

repair

a reason multicellular organisms undergo mitotic cell division, injury triggers cell division to replace damaged cells

interphase

long period of the cell cycle when the cells are not dividing

mitotic phase

short period of the cell cycle when the cell physically separates; chromosomes condense and separate

G1 phase

cells do their normal functions including protein production; first growth phase of the cell cycle

S phase

phase in the cell cycle where DNA is replicated

G0 phase/exit

phase where differentiated cells exit the cell cycle and do specific functions in the tissue they reside

G2 phase

more normal activities, duplication of organelles, getting ready for M phase; the second growth phase

identical

mitosis produces two daughter cells genetically ________ to the parent cell

gene

coding regions of DNA; code for mRNA that is made into proteins

proteins

DNA holds the recipes for making _________, and each cell gets a full copy of the recipes even if not all of them are made

building blocks of nucleotide monomers

1. phosphate group

2. 5-carbon sugar

3. nitrogenous base

nitrogenous base

the ___________ _______ varies between nucleotide monomers

cytosine

guanine pairs with ________ in a DNA double helix

adenine

thymine pairs with _________ in a DNA double helix

phosphodiester bonds

the bonds that hold the backbone of DNA structure together; covalent; hard to break; between the 5-carbon sugars

hydrogen bonds

the bonds that hold two DNA strands together; between nitrogenous bases; easier to break

phosphate

there is a _______ group on the 5th carbon of the 5-carbon sugar in a nucleotide

hydroxyl

there is a _________ group on the 3rd carbon of the 5-carbon sugar in a nucleotide

pyrimidines

the classification of cytosine and thymine

purines

the classification of guanine and adenine

anti-parallel

the two DNA strands in a double helix run _________ to each other

3'

DNA is built by the _____ end; this is due to the polarity of a DNA molecule

origin of replication (ori)

location where proteins in the replication complex bind to a DNA sequence and begin to separate DNA strands

circular

prokaryotes tend to have _______ chromosomes

one

prokaryotes tend to only have _____ ori per chromosome

linear

eukaryotes tend to have _______ chromosomes

multiple

eukaryotes tend to have _______ ori per chromosome

DNA helicase

separates the strands of the DNA double helix; breaks hydrogen bonds

ssBinding proteins

stabilizes single strands of DNA to prevent unwanted hydrogen bonds between basepairs; prevents complimentary nucleotides from rebinding

topoismerase

relieves strain caused by unwinding a twisty molecule

primase

lays down RNA primer; leaves a double strand with the 3'-OH group necessary for DNA polymerase to bind to and add nucleotides

initiation

phase in DNA synthesis where proteins assemble at the ori, DNA is unwound, and RNA primers are laid down

3'; 5'

DNA is read in the ___ to ___ direction by DNA polymerase

DNA polymerase III

a protein that adds DNA bases complementary to the template strand in order for form a new strand of DNA

5'; 3'

DNA polymerase only builds DNA in the ____ to ___ direction

elongation

phase in DNA synthesis where DNA polymerase binds and adds complementary DNA bases

leading strand

one of the two newly synthesized DNA strands at the replication fork during DNA replication; synthesized by DNA polymerase continuously in the 5' to 3' direction toward the replication fork

lagging strand

one of the two newly synthesized DNA strands at the replication fork during DNA replication; synthesized discontinuously away from the replication fork; requires multiple RNA primers and creates Okazaki fragments

the 3 additional steps the lagging strand needs to synthesize

1. RNA primers between Okazaki fragments

2. DNA polymerase I comes and fills in the nucleotides that were once RNA

3. DNA ligase creates covalent bonds in the backbone between Okazaki fragments

DNA polymerase I

a protein that removes RNA primers and replaces them with DNA nucleotides during DNA replication

DNA ligase

a protein that catalyzes the formation of phosphodiester bonds between Okazaki fragments to create one continuous strand of DNA

semi-conservative replication

the type of DNA replication done in human cells; new strands of DNA contain one strand from the parent cell and one new

template

Each single strand of unwound DNA can be used as a _______ for a new strand to be built

chromosome

a discrete, continuous molecule of DNA wrapped around protein; Eukaryotes contain multiple in linear form

sister chromatids

one or two identical attached copies that make up a replicated chromosome

centromere

a small part of chromosomes that attaches sister chromatids to each other

sister chromatids

by the end of S phase DNA is replicated and _______ ______ are formed attached by a centromere

histones

proteins that organize and compact DNA in the nucleus; condense chromosomes during mitosis

prophase

phase of mitosis where chromosomes condense and spindle fibers begin to form

prometaphase

phase of mitosis where the nuclear envelope breaks down; microtubules contact chromosomes at kinetochores

metaphase

phase of mitosis where chromosomes complete migration to the middle of the cell

cytoskeleton

mediates the movement of chromosomes during mitosis; uses the help of motor proteins

kinetochore

protein location on a chromosome centromere where microtubles (spindle fibers) attach; attached and breaks apart microtubles to allow for chromosome movement during mitosis

anaphase

phase in mitosis where sister chromatids separate into daughter chromosomes and are pulled to opposite poles of the spindle apparatus

telophase

phase in mitosis where the nuclear envelope reforms and chromosomes decondense

cytokinesis

phase where the cytoplasm divides ending in the complete formation of two identical daughter cells

microtubules

during cytokinesis in plants; _______ direct vesicles to the center of the spindle where they fuse to divide the cell in two

actin-myosin

during cytokinesis in animal cells; ____________ interactions pull plasma membrane inward to divide the cell in two

mitosis

bacterial cells do not undergo _________, instead they do binary fission