BIO 1114 - Ch 8 - DNA Replication, Binary Fission, and Mitosis

Steps of DNA replication

1) the helicase enzyme unwinds and separates the two DNA strands 2) the DNA polymerase enzyme assembles new DNA strands using nucleotides that are complementary to each exposed strand 3) the process ends with two identical double stranded DNA molecules

Which of the following undergo mitosis? Germ-line cells Fertilized cells Skin cells Muscle cells

2-4

malignant tumor

A cancerous tumor that is invasive enough to impair the functions of one or more organs.

Where does DNA come from?

A cell can copy its own DNA

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

sexual reproduction

A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents

Gene

A segment of DNA on a chromosome that codes for a specific trait

Meiosis

A specialized type of cell division that gives rise to nuclei that are genetically different from one another

What are the four bases of DNA?

Adenine, Thymine, Cytosine, Guanine

DNA polymerase

An enzyme that catalyzes the formation of the DNA molecule.

If the genetic material in a cell is damaged behind repair, a signaling protein may trigger _____

Apoptosis

Centromere

Area where the chromatids of a chromosome are attached

Genetic mutations cause a key role in causing ____

Cancer

G2 phase of interphase

Cell continues to grow but also prepares to divide, producing the proteins that will help coordinate mitosis

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

Cytokinesis in animal cells

Cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts The two nuclei are distributed into two forming daughter cells, which then physically separate Cleavage furrow forms

Anaphase (Mitosis)

Centrosomes split as sister chromatids separate and move to opposite poles of cell. At the same time, some microtubules in the spindle lengthen in a way that moves the poles further apart, stretching the cell

What's a collective term for all of the cell's DNA and its associated proteins?

Chromatin

Early Prophase (Mitosis)

Chromatin in nucleus condenses to form visible chromosomes, mitotic spindle forms from fibers in cytoskeleton or centrioles (animal). Centrosomes move to opposite poles

Metaphase (mitosis)

Chromosomes line up in the middle of the cell

homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure that come from each parent

Components of chromatin

DNA proteins for scaffolding Proteins for replication Proteins for transcription

Before a cell's nucleus and cytoplasm can split in two...

DNA replication must happen

A cell must package its DNA into a portable form that can easily move into the two ____ cells

Daughter

Each cancerous cell passes krs loss of cell cycle control to its _______ cells

Daughter

What does radiation therapy do?

Destroys cancer cells with minimal damage to normal cells

What does DNA polymerase do?

Discards mismatched nucleotides and inserts correct ones

Mitosis

Divides a eukaryotic cell's genetic information into two identical nuclei

What do cell cycle checkpoints do?

Ensure that a cell doesn't enter one stage or the cell cycle until the previous stage is complete

What copies DNA?

Enzymes called DNA polymerase

S phase of interphase

Enzymes replicate the cell's genetic material and repair damaged DNA

True or false: DNA replication occurs simultaneously at one point along a chromosome

False. Across many points

True or false: chemical signals that regulate the cell cycle don't have to be orecise

False. It's essential that it's precise

True or false: the daughter dells of mitosis have half as many chromosomes as the parent cell

False. They have the same amount

Ligase enzyme

Forms covalent bonds between adjacent DNA segments

Cytosine pairs with

Guanine (G)

Gern-line cells divide to produce

Haploid cells called gametes

The two members of a chromosome pair in diploid cells are called

Homologous chromosomes

What holds the strands of the DNA double helix together?

Hydrogen bonds between purines and pyrimidines.

sister chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase

cell plate

In a plant cell, midline of dividing cells. Becomes the cell wall eventually.

A cell spends most of its cycle during _____

Interphase

What part of the cell cycle begins immediately after interphase?

Mitosis

Late Prophase (Mitosis)

Nuclear membrane & nucleolus are broken down; chromosomes continue condensing & are clearly visible; spindle fibers called kinetochores attach to the centromere of each chromosome

Each strand of the double helix of DNA is composed of

Nucleotides

Examples of benign tumors

Papilloma (wart), Adenoma, Lipoma, Osteoma, Myoma, Angioma, Nevus, Meningioma, Chondroma

Does DNA replication precede or proceed cell division?

Precede

asexual reproduction

Process by which a single parent reproduces by itself

Fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell

DNA is transcribed into

RNA

Centromere

Region of a chromosome where the two sister chromatids attach

Chromatin are enzymes that help DNA do what?

Replicate it and transcribe it to RNA

Some cell cycle checkpoints

Screen for damaged DNA

origins of replication

Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides.

Most familiar forms of cancer

Solid tumors of the breast, lung, skin and other major organs

Centrosome

Structures that organize the mitotic spindle

Chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Traditional cancer treatment includes

Surgical removal, chemotherapy, radiation

DNA replication in preparation for cell division also requires

That the cell's DNA be unwound

daughter cells

The cells that are produced as a result of mitosis. These cells are identical to each other, and also to the original parent cell.

Adenine pairs with

Thymine (T)

Since cell division and cell death are in balance...

Tissue neither overgrows or shrinks

DNA's main function

To specify the recipes for all the proteins in a cell

True or false: a malignant tumor lacks a surrounding capsuke

True

True or false: cancer arises when cells divide out of control

True

True or false: many protists and multicellular eukaryotes also reproduce asexually

True

Benign tumors

Usually slow growing and harmless, unless they become large enough to disrupt nearby tissues or organs A tough capsule surrounding the tumor helps it from invading nearby tissues or spreading to other parts of the body

Zygote

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum

checkpoints in cell cycle

after G1, G2, metaphase

Genome

all of an organism's genetic material

Cancer

any malignant growth or tumor caused by abnormal and uncontrolled cell division.

G1 phase of interphase

cell grows: increase in size and synthesize new proteins and organelles

paired sister chromatids are joined to each other at the

centromere

Mutation

change in a DNA sequence that affects genetic information

cytokinesis in plant cells

divide from inside out using a cell plate in middle of cell

germ line cells

during zygote development, cells that are set aside from the somatic cells and that will eventually undergo meiosis to produce gametes

spindle

fanlike microtubule structure that helps coordinate the movement of chromosomes during mitosis

Meiosis produces

four genetically different haploid cells

Asexual reproduction generates

genetically identical offspring

three stages of eukaryotic cell cycle

interphase, mitosis, cytokinesis

What does chemotherapy do

kills rapidly dividing cells

tumor

mass of rapidly dividing cells that can damage surrounding tissue

What process accounts for the formation of a multicellular adult from a zygote and for asexual reproduction in protists and other eukaryotes?

mitosis

Cancer begins when

mutations of a single cell disrupt the normal cell cycle, causing cells to divide in an uncontrolled way

DNA is a double stranded

nucleic acid

Chromatids

one of two identical "sister" parts of a duplicated chromosome

Apoptosis

programmed cell death

Histones

protein molecules around which DNA is tightly coiled in chromatin

Nucleosome

repeating subunit of chromatin fibers, consisting of DNA coiled around 8 histones

In a human body, mitotic cell division occurs about 300 million times per minute and acts to

replace cells

cell cycle

series of events that cells go through as they grow and divide

After DNA replication chromosomes consist of two

sister chromatids

Gametes

sperm and egg cells

The _____ consists of microtubule fibers that move the chromosomes during mitosis

spindle

cleavage furrow

the first sign of cytokinesis during cell division in an animal cell; a shallow groove in the cell surface near the old metaphase plate

Telophase (mitosis)

the nuclei for the newly split cells form, the nucleoli reappear, and the chromosomes uncoils. Spindle disappears As this phase ends, the division of the genetic material is complete and the cell contains two nuclei- but not for long

metastasize

the process by which cancer spreads from one place to another

Sexual life cycle

the production of haploid gametes by meiosis, followed by the union of two gametes in sexual reproduction

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Diploid cells contain

two complete sets of chromosomes