unit 2 Flashcards
cells
what are organelles?
specialized structures with the cell that help the cell function
describe cell (plasma) membrane and its duties
surrounds the outsides of all cells and controls what goes in and out of the cell
made of the phospholipid bilayer (selectively permeable)
what is a cytoskeleton?
made of proteins, and threadlike fibers. it gives the cell shape and moves organelles around
what’s cytoplasm?
a jelly like substance that holds everything in place in the cell, it is the solution for chemical reactions
what is the nucleus?
it contains genetic material and protects the DNA that controls the cell’s activities
(has a nuclear envelope with “pores” that control what goes in and out)
what is the nucleolus?
it makes rRNA which make up ribosomes
what are ribosomes?
they’re made of proteins and rRNA
found on the rough ER and floating in cytoplasm
important because they make proteins!!
what is the Rough ER? (endoplasmic reticulum)
hugs the nucleus and has ribosomes on the surface, it makes proteins, then PACKAGES them for secretion and sends in through VESICLES to the Golgi apparatus
what is the Smooth ER?
its attached to the rough ER but it doesn’t have ribosomes. MAKES LIPIDS and stores Ca+2
what is the golgi apparatus?
it’s a folded membrane that recieves vesicles of protein FROM the ROugh ER
it processes, sorts and sends proteins where neeed (like the post office of the cell!)
what are lysosomes?
they contain enzymes that break down dead stuff and can do programmed cell death (basically the recycling bin of the cell)
what are vacuoles
they are used for storage in plant (large central one) and animal cells (small and numerous)
what are centrioles/centrosomes
they appear during cell division and help the cell divide
made of microtubules
(2 centrioles together is a centrosome)
what is the Cilia?
short and numerous that move fluid along the cell’s surface, like mini oars
associated with the cytoskeleton
what is the flagella?
long and few of them are on the cell, they move the entire cell through extracellular fluid.
associated with the cytoskeleton
what is the mitochondria?
the powerhouse of the cell. it has an inner membrane and matrix
where cellular respiration happens
it breaks down chemical energy in food to release usable energy
what is chloroplast?
where photosynthesis happens (2 parts: grana and stoma)
converts light energy from sun to chemical energy in sugar
found only in plant cells
what is a cell wall?
protects and maintains the shape of the cell
made of cellulose of chitin (fungi) and peptidoglycan (bacteria)
mostly found only in plant cells
what is the central vacuole?
it’s one massive central structure, a storage center in plants
what is the difference between dynamic and static equilibrium? (with regards to homeostasis)
dynamic equilibrium is maintained and the conditions stay within a range
static equilibrium happens afterward when the system has stopped and is at rest
what is the relationship between a response to stimuli and homeostasis?
homeostasis is the need of an organism to stay stable by regulating internal conditions. stimuli is a change in environment. the response is what happens as a result to the stimuli and the organism trying to maintain homeostasis
what is the difference between positive and negative feedback loops?
positive feedback loops: the output of the system intensifies the response (ex. human childbirth, fruit ripening)
negative feedback loops: a counter response is triggered to get the system back to a set point (ex. human body temperature, blood sugar regulation)
what is the role of the cell membrane in maintaining homeostasis on a cellular level? what substances can and cannot pass thru easily?
the cell membrane controls what goes in and out of the cell. it is selectively permeable. small, hydrophobic, and/or neutral items can pass through easily. polar and larger molecules cannot.
what’s the difference between passive and active transport?
passive transport doesn’t require extra energy, while active transport does. passive transport moves molecules down the concentration gradient, while active transport does the opposite.
what are the 6 types of transport and what molecules are used?
simple diffusion
- spreading out of molecules until equilibrium is reached (move from high to low concentration)
- ex. O2 and CO2
facilitated diffusion
- transport protein (like a channel) helps facilitate the diffusion of molecules that normally couldn’t pass through the membrane
- ex. large molecules (glucose and polar molecules (CA+2)
osmosis
- simple diffusion of water across the membrane, water molecules move down a concentration gradient from high to low area until equilibrium is reached
molecular pumps
- when a cell uses energy to pump molecules across the membrane, against the gradient through a protein channel
- ex. potassium K+, chlorine Cl-, sodium Na+
endocytosis
uses vesicles to move large particles INTO the cell (phagocytosis, cell eating; pinocytosis, cell drinking)
exocytosis
- uses vesicles to export materials OUT of the cell
what is the difference between hypotonic, isotonic, and hypertonic solutions?
hypotonic: water is higher than the cell’s cytoplasm, cell swells
isotonic: equal water to cytoplasm, cell stays the same
hypertonic: water is lower than the cell’s cytoplasm, cell shrivels
what is homeostasis?
need of an organism to stay stable by regulating internal conditions
what is a solute?
what gets dissolved (ex. lemonade powder)
what is a solvent?
does the dissolving (ex. water)
what is a solution?
uniform mixture of 2 or more substances (ex. lemonade)
what is concentration?
amount of solute dissovled in the solvent (symbol for abbreviation: [])
what is the concentration gradient?
the difference in concentration of substance from one location to another
what is phagocytosis?
in endocytosis; cell eating
cell engulfs particle into vesicle and digests it
what is pinocytosis?
in endocytosis; cell drinking”
cell engulfs liquids into vesicles and digests them
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 haveing a particular function
what are the levels of organization from cell->organsim that result from differentiation?
cell: most basic unit of life with the characteristics of life
tissue: a 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 disapeears
b. Metaphase:spindle fibers connect to centromere, chromosomes line it up to the middle of the cell
c. anaphase: sister chromatids separate, becoming individual chromosomes
d. telophase: chromosomes decondense and look like chomotin again, nuclear membrane reforms, cytokensis begins - cytokensis: the division of the cytoplasm into 2 cells
what are the differences between cytokensis in plants 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 controlled 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 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 types of specialized cells
what is a 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
what are chromosomes?
one line continuous thread of DNA that consists of thousands of genes and regulatory info
what is a gene?
section of the DNA that contains the instructions for making a protein
what are sister chromatids?
2 identical chromotids
what is a centromere?
region of the condensed chromosomes that look pinched->X
what are telomere?
ends of the DNA molecule
what is cancer?
uncontrolled cell division
what does metastasize mean?
spreading of one disease from one organ to another
what are carcinogens?
cancer-causing agents, chemicals that cause cancer by mutating DNA
(ex. tobacco smoke, asbestos, etc)
