Chapter 8 DNA REP & Cell Div Flashcards
Cell division has a role in ________, ________, & __________.
Reproduction, growth, and development.
Cell division produces a ______ supply of ________ cells.
Continuous
Replacement
What are the 4 types of cell division?
Asexual reproduction, sexual reproduction, mitosis and meiosis.
Explain a sexual reproduction.
Replicating genetic material and splitting the contents of one cell into two. Generate identical offspring. Binary fission. (One parent)
Explain sexual reproduction.
Production of a spring from two different parents, offspring genetically different.
What are gametes? And how are those produce?
Sex cells. (sperm and egg cells)
Meiosis
At what point do sex cells (gametes) combine?
At fertilization
What is meiosis?
Division of genetic material that halves the chromosome number and yields genetically variable (different) gametes.
What is mitosis, and when does it begin?
Division of genetic material that yields two genetically identical daughter cells. Begins after fertilization.
Mitotic cell division allow organisms to…
Grow, repair damaged tissue, regenerate body parts (some species), reproduce a sexually (protist).
What is a apoptosis?
Cell death that is a normal part of development. aka: “programmed cell death”
What is the genome?
All genetic material in the cell
What must occur before cell division?
DNA replication, it must duplicate its entire genome
What is a chromosome?
Single molecule of DNA and associated proteins
How many chromosomes does bacteria have? Human?
1 circular and 46
What are the steps to DNA replication?
Enzyme Helicase unwinds and holds DNA apart. hydrogen bonds are broken and DNA polymerase adds new nucleotides complementary to the bases on exposed strand. Hydrogen bonds form between bases (complementary).Ligases form covalent bonds between adjacent DNA segments. The process inns with two identical double-stranded DNA molecules.
What is the job of the enzyme helicase?
Unwind and holds DNA apart
What is the job of the enzyme DNA polymerase?
Copies complementary DNA to both sides, and proofreads. Is incredibly accurate.
What is the job of the enzyme ligase?
Forms covalent bonds between adjacent DNA segments.
What is semi-conservative replication?
Keeping half of the old parent DNA strand into new daughter strands.
If DNA polymerase does not correct a mistake In DNA Replication or a cell is exposed to a mutagen, what can happen?
Mutation (any change in a cell’s DNA sequence)
What is binary fission?
An asexual process that replicates DNA and distributes it into two daughter cells.
What are the four steps of binary fission?
- Parent cell contains one circular chromosome.
- DNA replicates and attaches to cell membrane.
- Membrane growth between the two attachment points move the DNA molecule apart as new cell wall material is deposited.
- The result of binary fission is two daughter cells, each identical to the original.
What type of cells use binary fission?
Bacteria and Archaea
What occurs when DNA is loosely packed?
DNA replication and protein synthesis
What occurs when DNA is condensed into chromosomes?
Cell division
What is chromatin?
DNA and associated proteins in the nucleus
What is a chromosome?
A molecule of DNA wrapped around the proteins
What is a chromatid?
One of two identical attach copies of a replicated chromosome
What is a centromere?
A small region of a chromosome were sister chromatids attach to each other
What is a nucleosome?
Stretch of DNA wrapped around eight proteins called histones
What are histones?
Proteins that are associated with DNA. Eight at a time wrapped in the nucleosome.
What is the Kinetochore?
Protein molecule that attaches a sister chromatid to a spindle fiber
Mitosis is the division of ________.
Nucleus
What is the division of the cell itself?
Cytokinesis
What phases occur in interphase? And what occurs in each of these phases?
G1 (gap)-growth, normal cell function
S(synthesis)-replication of DNA
G2(gap)-growth, prep to divide
What are the stages of Mitosis?
Prophase
Metaphase
Anaphase
Telophase
Explain what occurs in prophase.
Chromosomes condense, spindles form, nuclear membrane (envelope) breaks up, spindles attach to chromosomes at Kinetochore (proteins).
What occurs in metaphase?
Chromosomes meet in the middle
What occurs in anaphase?
Chromosomes pull apart
What occurs in Tele phase?
Nuclear membrane and nucleolus reform, chromosomes de-condense, & spindles disappear.
What occurs in cytokinesis?
Forming of two identical daughter cells
What occurs after the final step cytokinesis in the cell cycle?
Cells resume normal function or enter cell division (G1) interphase to be divided once again
In an animal cell, what is the first sign of cytokinesis?
Cleavage furrow (A slight indentation around the cells equator)
What is the first sign of cell wall construction in a plant cell?
Cell plate (a line separating the forming cells)
How is the cell cycle regulated?
“Checkpoints” control stages
What is a tumor?
An abnormal mass of tissue.
What does benign mean?
Slow-growing and usually harmless surrounded by a tough capsule preventing metastasizing.
What does malignant mean?
A tumor invading adjacent tissue. Does NOT have surrounding tissue like benign tumor.
What does it mean when a tumor/cancer will metastasize?
Cells can break away from original mass and travel in bloodstream or emphatic system and colonize in other areas of the body.
What are two aspects of life that can increase cancer risk?
Genes and the environment
What are three cancer treatments?
Surgery, (drugs) chemotherapy, & radiation
Explain the gene regulation, DNA availability.
Un-needed DNA is tagged so proteins in the cell signal the cell to fold that section of DNA too tightly for RNA polymerase to access deeming it inactive.
