Concept 3 Flashcards
what is the order of events from egg to sperm to embryo?
when the egg is fertilized by the sperm, it goes into repeated cell division. mitosis creates many identical cells. the cells are differentiated and become tissues-> organs-> organ systems-> embryo
what is the difference between specialized cells and stem cells?
stem cells are undifferentiated, until they are made into a specialized cell, now having a particular function.
what are the levels of organization from cell-> organism that result from differentiation?
cell: most basic unit of life with the characteristics of life
tissue: group of cells working together for a common function
organ: set of tissues working together for a common function
organ system: set of organs working together for a common function
organism: made of an organ system, 1 individual member of a species
what are the 2 main purposes for cell division?
growth and repair
what are all the phases of a cell cycle?
- interphase- the growth phase of the cell
a. G1 Gap 1 phase: cell grows and makes proteins (most of the time is spent here) - S Phase (synthesis phase): DNA replication occurs, number of chromosomes double.
- G2 Gap 2 phase: more cell growth and protein synthesis
- Mitosis: when the cell divides (1 cell becomes 2 daughter cells)
a. prophase: chromosomes condense, spindle fibers form, nuclear membrane disappears
b. metaphase: spindle fibers connect to centromere, chromosomes line up it the middle of the cell
c. anaphase: sister chromatids separate, becoming individual chromosomes
d. telophase: chromosomes decondense and look like chromotin again, nuclear membrane reforms, cytokinesis begins - cytokenisis: the division of the cytoplasm into 2 cells
what are the differences between cytokinesis in plant and animal cells?
plant cells: cell plate forms midway between nuclei and gradually develops a membrane
animal cells: cleavage furrow is made that pinches cell into 2 equal parts
how do cells know when they need to divide?
the cycle is contolled by a chemical control system that starts and stops in the cell cycle
external- signals coming from the outside like hormones, nutrients, etc
internal- signals that come from the cells own nucleus like DNA inside of the cell
what are checkpoints and apoptosis role in the cell cycle?
checkpoints are “stop and go” signals that regulate the cycle
apoptosis is programmed cell death. internal/external signals activate genes that produce def destructive enzymes.
what are the 2 tumor types? what is a tumor?
a tumor is a clump of cells that divide uncontrollably
benign- abnormal cells remain clustered together. may be harmless and easy to remove
malignant- cancer cells that break away from the tumor and move to other parts of the body = more tumors
what are several causes for cancer?
- biological factors
- lifestyle choices
- viruses
- exposure to carcinogens (cancer causing agents)
what is differentiation?
a process that creates special structures and functions
what are stem cells?
undifferentiated cells that become differentiated into 1 or more type of specialized cells
what is gastrula?
embryo with 3 differentiated germ layers
what is organogenesis?
the process of body organ and organ system formation that follows gastruation
what is the cell cycle?
the repeated pattern of growth, DNA duplication, and cell division that occurs in EUKARYOTIC cells
