Ch 3. The cell Flashcards
cell/plasma membrane
bilayer of:
1. phospholipids- diglycerides and form a bilayer. Permits non-polar substances to pass through but blocks polar or charged substances from passing through.
2. cholesterol- stabilizes the cell membrane
3. Carrier enzyme or carrier protein- it’s a protein that is part of the cell membrane and helps transports materials across the membrane.
Important to nerve + muscle cells bc of electrical impulses
Membrane proteins
(Channel proteins , Receptor sites, Antigens)
- Channel proteins or pores- permit the passage of materials into and out of the cell
- Receptor sites- a type of protein that recognizes certain hormones or chemicals needed by the cell
- Antigens- proteins with an oligosaccharide identify “self”. Involved in tissue typing used by white blood cells to distinguish pathogens
nucleus + nucleolus
the membrane-bound organelle which contains our DNA and controls all cellular activities.
All your body’s cells have a nucleus except red blood cells (RBC’s).
Nucleolus- a smaller sphere inside the nucleus where ribosomes are made.
chromosomes
rod shaped structures containing super condensed DNA & proteins. Appear when the cell is ready to divide.
Humans have 23 pairs or 46 total.
chromatin
non-condensed DNA found in the nucleus. Our DNA usually takes this form.
Gene
is the genetic code for a protein. One gene-one protein.
Cytosol
-is the watery portion of the cytoplasm. It contains many dissolved minerals, gases, proteins, etc.
Cytoskeleton
protein microfilaments which gives the cell shape and support
ribosomes
make proteins and are found on the rough ER or free floating in the cytosol
Golgi Apparatis
series of flattened sacs which process materials for secretion out of the cell.
Carbohydrates are synthesixed withing this organelle
mitochondria
site of ATP synthesis. Inner folds are called cristae. Contain their own DNA inherited maternally.
lysosome
contain digestive enzymes
Proteasomes
barrel-shaped organelles that contain protein digesting enzymes
important for cell division and embryonic development
Centrioles
rod shaped structures which organize the spindle fibers during cell division.
cillia
short hair-like projections that work in unison to MOVE OBJECTS across the free surface. Found in the respiratory tract & fallopian tubes.
FLAGELLA
longer hair-like projection used for movement. Ex: sperm
Mircovilli
small folds found on the surface of some cells of the digestive tract which increase surface area of the cell for absorption of nutrients.
Endoplasmic reticulum
passageway for transport of materials within the cell
Rough ER- has ribosomes on its surface
synthesizes proteins
Smooth ER- synthesize lipids and detoxify chemicals
PASSIVE CELLULAR TRANSPORT
1. Diffusion- the movement of molecules from an area of high concentration to an area of lower concentration.
Ex: oxygen & carbon dioxide
2. Osmosis- diffusion of water across a membrane. Water moves from high water conc. to lower water conc. occurs in kidneys reabsorb large amounts of water to prevent its lost in urine/small intestine absorb water from digest food
3. Facilitated diffusion- a process where a substance crosses the cell membrane using a protein (enzyme) carrier. Ex: glucose
osmosis
- Isotonic- equal parts of solutes
- Hypotonic solution- having a lower concentration of dissolved particles. Will cause a cell to swell. Ex: distilled water
- Hypertonic solution- having a higher concentration of dissolved particles. Will cause a cell to shrink. Ex: ocean water.
ACTIVE CELLULAR TRANSPORT
-Requires ATP
b/c you’re moving from moving against the concentration gradient
1. Sodium-Potassium Pump (Na/K Pump)-
2. Filtration-
3. Endocytosis-
4. Exocytosis-
Sodium-Potassium Pump (Na/K Pump)-
a very important ion pump in nerve and muscle cells.
Moves Na & K against their conc gradients. 3 Na out:2 K in
Filtration-
requires the use of mechanical pressure.
Endocytosis
a process by which materials enter the cell by vesicles.
2 Types:
Phagocytosis- engulfing another cell or large particle. Ex: white blood cell engulfing a bacteria.
Pinocytosis- engulfing fluids or smaller particles. Ex: kidneys reabsorb proteins so not loss in urine
Exocytosis-
the process by which materials are secreted by vesicles.
codon
sequence of three bases (triplet code) in mRNA which codes for a particular amino acid.
DNA
a double strand of nucleotides in the shape of a double helix.
base pairing:
Adenine-Thymine
Guanine- Cytosine
Uracil- a nucleotide in RNA which takes the place of Thymine. A-U base pairing.
mRNA
messenger RNA takes the genetic code from DNA in the nucleus out to the ribosomes for translation. mRNA is a series of codons
Transcription
copying the DNA to mRNA. “DNA to RNA”
tRNA
transfer RNA is found in the cytoplasm and contains the anticodons. It also has a specific amino acid attached.
Translation
is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins. “DNA to Protein”
mitosis
cell reproduction where a cell divides and produces two identical daughter cells. Occurs in all cells except reproductive cells. Necessary for growth and repair of tissues.
meiosis (and the 2 types)
cell division where a reproductive cell divides and reduces the chromosome by a half to produce haploid gametes. Haploid n=23…diploid 2n=46
Oogenesis- meiosis in the ovaries produce egg cell.
Spermatogenesis- meiosis in the testes produce sperm cells.
aging of cells
telomeres- the ends of chromosomes. after each cell division, a small portion of the telomeres is lost resulting in a loss of the chromosome and/or DNA.
Chaperones- proteins responsible for maintaining cellular activities. They work less effectively resulting in a build-up of damaged proteins in the cell. The accumulation of damaged proteins interferes with proper cellular function.
