2- Cells Flashcards
How many cells does the human body have?
50 to 100 trillion cells
What two scientists said all living things are cells?
Matthias Schleiden and Theodore Schwann
What is the outer cell membrane called?
Plasma Membrane or Plasmalemma
What does lemma mean?
sheath, husk
What does the fluid mosaic model depict?
The plasma membrane as a lipid bilayer
Polar heads are attracted to…?
Water
Non polar lines up with?
Center of the membrane
What percentage of sugar groups are attached to the lipids in cell membranes?
10%
What are “sugar-fats” called?
glycolipids
Cholesterol does what to the membrane?
Makes it more rigid and increases impermeability to water and water-solubles molecules
What are the two plasma membrane proteins?
Integral proteins and peripheral proteins
Integral proteins
firmly integrated to the lipid bilayer
What is a transmembrane protein?
Its spans the whole width of the bilayer membrane (across)
Peripheral proteins
Attach loosely to the membranes surfaces on cytoplasmic side and helps support membrane
What two things attach to form glycoproteins?
carbohydrate molecule chains and integral proteins
What coats the external part of the cell?
Glycocalyx “sugar covering”
This helps it be sticky and bind to other cells
What is a distinctive marker that cells recognize each other by?
Glycocalyx have different smells
Functions of the plasma membrane
1- protective barrier
2- molecules bond to receptor proteins molecule than can induce a change in cell activity
3- controls what enters and exits cell
simple diffusion
things that can travel freely across plasma membrane
What things use simple diffusion?
- oxygen
- carbon dioxide
- fat-soluble molecules
osmosis
the diffusion of water molecules across membrane
What molecules use facilitated diffusion?
- glucose
- amino acids
- ions
facilitated diffusion
integral proteins are used to carry/pump molecules across the membrane down the concentration gradient
active transport
integral proteins are used to move molecules against concentration gradient
How are macromolecules and large solid particles transported?
vesicular
or
bulk transport
What are the two types of bulk transport?
exocytosis
endocytosis
endocytosis
macromolecules enter the cell
Membrane wall sacs that transport
vesicle
3 Type of endocytosis
1- phagocytosis
2- pinocytosis
3- receptor-mediated endocytosis
Sac formed in phagocytosis
phagosome
lysosome
organelle containing digestive enzymes that break down the contents of the phagosome
What cells are the best at phagocytosis?
white blood cells
pinocytosis
engulfs drops of extracellular fluid, no receptors
What do phagosomes combine with to digest contents in phagocytosis?
lysosomes
ribosomes
S: made of RNA & Protein free or attached to rough ER F: protein synthesis occurs here
Rough endoplasmic reticulum
S:
membrane enclosing cavity cisterna
studded with ribosomes
F:
makes proteins secreted from cell
makes the cells membranes
smooth endoplasmic reticulum
S:
sacs and tubules free of ribosomes
F:
lipid & steroid synthesis, lipid metabolism, drug detoxification
golgi apparatus
S: stack of smooth membrane sacs
F: Packages/segregates proteins for exocytosis, inclusion in lysosomes, incorporation into plasma membrane
lysosomes
S: membranous sac containing acid hydrolases
F: intracellular digestion
mitochondria
S: bean shaped double membrane, inner membrane folds called cristae
F: ATP synthesis, powerhouse/energy of cell
peroxisomes
S: membranous sacs of oxidase enzymes
F: enzymes detoxify substances
catalase enzyme breaks down hydrogen peroxide, breaks down poisons that enter cell
microfilaments
S: filament of contractile protein actin
F: muscle contraction, intracellular movement, forms cells cytoskeleton
intermediate filaments
S: protein fibers
F: stabilizes cytoskeleton, resists tension forces acting on cell
microtubules
S: cylinder like made of tubulin proteins
F: form centrioles, give cell shape, intracell/cell movement,
centrioles
S: paired cylinder like bodies, composed of 9 triplets of microtubules
F: organize microtubule network in mitosis (form spindle and asters), form bases of cilia and flagella
plasma membrane
S: double layer of lipids (phosopholipids, cholesterol, etc), proteins embedded, some attached sugar groups
F: cell barrier, transports substances in and out, proteins act as receptors
cytoplasm
has fluid cytosol with dissolved solutes, inclusion
nucleus
S: surrounded by nuclear envelope, nucleoplasm, nucleoli, and chromatin
F: control center of the cell, gene info, instructions for protein synthesis
nuclear envelope
S: double membrane pierced by pores, continuous with cytoplasmic ER
F: seperates nucleoplasm and cytoplasm, regulates passage of substances to/from nucleus
nucleoli
S: dense spherical bodies
F: ribosome subunit manufacturer
chromatin
S: threadlike composed of DNA
F: DNA constitutes genes
matrix
jelly-like substance in mitochondria
What transport uses energy?
active transport
What does the cytoskeleton do?
rods running through cytosol that act as the cells bones, muscles and ligaments and supports cell structure and generating cell movement
What are ribosomes made of?
Ribosomal RNA (ribonucleic acid)
What do ribosomes do?
produce proteins for cellular/extracellular function
What is linked together to form protein molecules in ribosomes?
amino acids
this is called translation
What do ribosomes attach to rough er do?
Make proteins for the cell membrane or exocytosis
flagellum
long whiplike extension of plasma membrane of some bacteria and sperm cells propels the cell
cilia
motile, hairlike projection from apical surface of epithelial cels
microvilli
immotile cell projections on free surface of epithelia , anchor sheets of mucus or increase surface area for absorption
vesicle
small liquid filled sac
Difference between vesicle and vacuole?
Vacuoles are used as storage areas and vesicles are used for transport of storage
How large is the nucleus?
5 micrometers
What are the 4 parts of the nucleus?
1- nuclear envelope
2- nucleolus
3- chromatin
4- chromosomes
macrophage
cell that fights disease
What maintains the shape of the nucleus?
nuclear lamina
nuclear pores
- bracelet shaped complex of more than 22 proteins
- allows large molecules to pass in and out
What routinely travels through nuclear pores?
protein and RNA molecules
Jelly-like fluid in the nucleus?
nucleoplasm
Cell Cycle
1: Interphase G1 S G2 2: Early Prophase - First phase 3: Late Prophase 4: Metaphase- Second phase 5: Anaphase- Third Phase 6: Telophase and Cytokinesis- Final phase
Interphase
chromatin extended/condensed
G1- centrioles begin replication
S- DNA replicated
G2- centriole replication complete
Early Prophase
Chromatin > Chromosomes > Identical Chromatids
(shaped like X)
Held together at centromere
Nucleoli and Cytoskeleton microtubules disassemble
Asters extend microtubules
Late Prophase
Nuclear envelope disassembles
microtubules extend from centrosomes and attach to centromeres
Metaphase
Chromosomes align at the middle of the cell
Chromatids are separated form each other by enzymes
Anaphase
Centromeres split apart
Spindle fibers pull chromosomes to opposite ends
Cell elongates
Chromosomes look v shaped and face each other
Telophase and cytokinesis
T: Identical sets of chromosomes nuclear envelopes reassembles nucleoli reappear mitotic spindle breaks down C: Contractile microfilaments squeeze cells apart
