DNA Replication, Binary Fission, and Mitosis Flashcards

Flashcards about DNA Replication, Binary Fission, and Mitosis

What process do bacteria and some single-celled eukaryotes use for cell division?

Binary Fission

What process do most eukaryotic cells use for cell division?

Mitosis

What is a gene?

A segment of DNA with instructions for RNA or protein

What is a genome?

The sum of an organism’s DNA

Where is the prokaryotic genome located?

In the nucleoid region (central region of cell)

What are plasmids?

Smaller DNA circles that contain one/ a few genes, found in prokaryotes

Where is the eukaryotic genome located?

In the nucleus

What are histones?

“Packing proteins” associated with the eukaryotic genome

What is a karyotype?

The general form of the nucleus

What are autosomes?

22 pairs of non-sex chromosomes in humans

What determines biological sex?

Sex chromosomes (23rd pair)

What is differential gene expression?

Results in different cell types from the same set of instructions

What is cell theory?

All cells come from pre-existing cells

Through what process do cells reproduce?

Cell division: One “parent” cell duplicates all cellular contents then divides (splits) into two new “daughter” cells

What is meiosis?

Modified cell division process for sex cells (sperm and eggs)

What type of cells use mitosis?

Cell division in body cells (somatic cells) in multicellular organisms

What is apoptosis?

Programmed cell death regulated by caspases

What are caspases?

Protein-degrading enzymes in every cell awaiting an activation signal for apoptosis

When does DNA replication occur?

S phase (“Synthesis” phase)

What are origins of replication?

Specific DNA sequences signal where to begin replicating genome (~30,000-50,000 in humans)

What is a replication fork?

Formed when the DNA strands split at the origins of replication.

What is semi-conservative replication?

Each “parental” strand serves as template for new complementary strand

Name 3 proteins required for DNA replication

Helicase, DNA polymerase, Ligase

What is the function of ligase?

To tie up or join

What is binary fission?

Cell division in prokaryotes

What are the two mechanisms of prokaryote evolution?

Random DNA mutations and Horizontal gene transfer

What are the three mechanisms of horizontal gene transfer in prokaryotes?

Transformation, Conjugation, Transduction

What is naked DNA?

DNA not associated with any histone proteins

What is chromatin?

DNA is wrapped around histone proteins in a loose configuration

What are chromosomes?

Highly condensed (compacted) chromatin, typically found only during active cell division/ mitosis

What are homologous chromosomes?

Chromosome pairs that contain the same genes, one set from egg (maternal), one set from sperm (paternal)

Which sub-phase of interphase does DNA replication occur?

S phase

Name the four phases of mitosis.

Prophase, Metaphase, Anaphase, Telophase

What is cytokinesis?

The cytoplasm is split between new cells then separated with new cell membrane

What is the function of centrosomes?

Organelle made of 2 centrioles that makes and organizes microtubules during mitosis

What happens in Prophase of Mitosis?

DNA condenses into most compact chromosome form, Nuclear membrane disintegrates, Centrosome copies move to the “poles” & synthesize microtubule “spindle fibers”, Spindle fibers extend toward center and attach to centromeres of chromosomes

What happens in Metaphase in mitosis?

Nuclear membrane has completely disintegrated, Microtubules have attached to sister chromatids of each chromosome, Microtubules have formed mitotic spindle (cage-like structure), All 46 chromosomes lined up single-file at the cell midline, equator, or metaphase plate

What happens in Anaphase in mitosis?

Microtubules begin to pull sister chromatids apart toward opposite poles of cell, Cell membrane begins to elongate

What happens in Telophase in mitosis?

Chromosomes de-condense into chromatin, 2 nuclear membranes form, Spindle fiber microtubules begin to disintegrate, In animal cells, two sets of protein filaments form at midline between nuclei

How does cytokinesis occur in animal cells?

Contractile ring of proteins make cleavage furrow and cells pinch off

How does cytokinesis occur in plant cells?

Cell wall-containing vesicles are sent to the midline (cell plate) between nuclei, Vesicles fuse and cell wall is established

What are cell cycle checkpoints?

The cell has internal controls to ensure it is ready to progress to the next phase of cell cycle

What is cancer?

A class of diseases characterized by malignant cell growth in the body

What is a tumor?

A mass of cells undergoing uncontrolled cell division

What are benign tumors?

Uncontrolled cell division contained in a tough capsule: size-limited and does not spread

What are malignant tumors?

Lack a capsule and can enter into circulatory systems and seed new regions of the body