Cellular Reproduction Flashcards
Name three reasons why cells divide and reproduce in the human body.
Growth
Replacement
Reproduction
How many cells divide each second in the human body?
Millions of cells divide each minute in the human body.
What are two sub-reasons for replacement as a reason for cells to divide?
Replacement - of lost cells due to a wound or injury
Replacement - of damaged cells
Approximately how many cells are in the grown human body?
Approximately 60 trillion cells are in the grown human body.
What is asexual reproduction?
Asexual reproduction is the creation of offspring by a single parent, without the participation of sperm and egg.
What types of organisms reproduce via asexual reproduction?
Single-celled organisms (ex. Amoeba)
Some multi-cellular organisms (ex. sea-star, spider-plant)
What type of offspring does asexual reproduction produce?
Asexual reproduction produces genetically identical offspring (identical to the parent cell/cells).
Sexual Reproduction
Creation of offspring by fertilization of an egg by a sperm.
Mitosis
Division of a single nucleus into two genetically identical “daughter” nuclei.
Give two instances in which cells would use mitosis.
Growth and maintenance
Asexual reproduction
Meiosis
Special type of cell division in which egg and sperm cells are produced.
Name an instance in which meiosis would be used for cell division.
Sexual reproduction
Where are the majority of eukaryotic chromosomes found?
The majority of eukaryotic chromosomes are found in the cell nucleus.
What does a eukaryotic chromosome contain?
Each eukaryotic chromosome contains a very long DNA molecule with thousands of genes.
Genes
Discrete units of hereditary information
What are eukaryotic chromosomes made up of?
Eukaryotic chromosomes are made up of chromatin.
Chromatin
Combination of DNA and protein molecules
What functions do proteins do with eukaryotic chromosomes?
Proteins organize chromosomes and help control activity (e.g. histones).
What is interphase?
Interphase is the part of the cell cycle in which there is cell growth, chromosomes are duplicated, and centrosomes emerge.
What percentage of the cell cycle is interphase?
Interphase is 90% of the cell cycle.
Centrosomes
Microtubule organizing center
Name the three stages of interphase.
G1
S
G2
G1 Phase of Interphase
In the G1 phase of interphase, the cellular contents (excluding the chromosomes) are duplicated.
S Phase of Interphase
In the S phase of interphase, each of the 46 chromosomes is duplicated by the cell.
G2 Phase of Interphase
In the G2 phase of interphase, the cell double checks the duplicated chromosomes for error, making any needed repairs.
Name the four stages of mitosis.
Prophase
Metaphase
Anaphase
Telophase
When does interphase occur?
Interphase occurs before mitosis.
What occurs in cytokinesis?
Cytoplasm divides during cytokinesis.
When does cytokinesis occur?
Cytokinesis occurs ‘after’ mitosis.
Give the four things (in order) that happen in the prophase of mitosis.
Chromatin fibers coil into chromosome with two “sister”
chromatids joined at centromere
Spindle microtubules appear on centrosomes
Nuclear envelope breaks up
Spindle microtubules attach to chromosomes
What occurs in the metaphase of mitosis?
In the metaphase of mitosis, chromosomes align on a “metaphase plate” and there is a centrosome “tug of war”.
What occurs in the anaphase stage of mitosis?
In the anaphase stage of mitosis, sister chromatids separate into “daughter” chromosomes.
Give the three things (in order) that occur in the telophase phase of mitosis.
Nuclear envelopes form
Chromosomes uncoil
Spindle fibers disappear
How, precisely, does cytokinesis occur?
Two “daughter” cells are formed when a cleavage furrow pinches the parent cell in two (in animal cells).
Cell Cycle Control System
Special proteins that trigger and coordinate activities in the cell cycle.
How do cancer cells respond to the cell cycle control system?
Cancer cells do not respond normally to the cell cycle control system (they do not stop reproducing when the cell cycle control system says to stop).
How does the immune system relate to a cancer cell?
The immune system may detect and destroy the cancer cell - but it will not always do so, and if it doesn’t detect and destroy the cancer cell, a tumor will occur.
Tumor
An abnormally growing mass of body cells.
Benign Tumor
An abnormal mass of cells that remains at its original site in the body.
Malignant Tumor
An abnormal tissue mass that can spread into neighboring tissue and to other parts of the body (i.e. Metastasis has occurred). This is colloquially known as cancer.
How are the forms of cancer named?
The forms of cancer are named according to where they originate.
Carcinomas
Cancers that originate in internal or external coverings (epithelial cells) of the body, e.g. skin, intestine, breast, lung, prostate, etc.
Sarcomas
Form of cancer that originates in tissues that support the body (e.g. muscle, bone, etc.).
Leukemias
Cancers that originate in the blood.
Lymphomas
Cancers that originate in the lymphatic tissue.
Give the three primary types of cancer treatment (not including the newer therapies).
Surgery
Radiation Therapy
Chemotherapy
Describe surgery as a form of cancer treatment.
Surgery is a localized form of cancer treatment in which the cancer cells are cut out, but it risks leaving some behind.
Describe radiation therapy as a form of cancer treatment.
Radiation therapy is a localized form of cancer in treatment that sends high-energy waves at the cancerous areas, or through radioactive implants at the cancerous areas.
Describe chemotherapy as a form of cancer treatment.
Chemotherapy is a form of cancer treatment that treats the entire body. It is attempted to customize it for the type of cancer, and it targets rapidly reproducing cells. Bone marrow transplants are sometimes needed.
Give the two types of new therapies for cancer treatment.
Immunotherapy
p53 gene therapy
Immunotherapy
Immune cells are genetically altered to bear tumor’s antigens at their surface, which results in the production of cytokines; the immune system (cytotoxic T cells) then attacks the tumor.
p53 gene therapy
A form of cancer treatment in which apoptosis is triggered in cancer cells.
