openstax ch. 3 - the cell

cell def

basic structure and functional unit of living organisms

cell membrane def

outer limit of the cell

cell membrane components

• selectively permeable

• phospholipid bilayer

what does it mean to be selectively permeable?

when only certain things can pass in and out of the cell

what type of layer is the cell membrane?

phospholipid bilayer

how many heads and tails do phospholipid bilayers have?

• 2 heads

• 2 tails

what forms the surface of the phospholipid bilayer?

the two hydrophilic heads

what forms the tails of the phospholipid bilayer?

the two hydrophobic tails

what are the tails of the phospholipid bilayer made up of?

• one saturated fatty acid tail

• one unsaturated fatty acid tail

what happens to water when it tries to pass thru the phospholipid bilayer?

• it only reaches past the head, then it stops

  • the head is hydrophilic while the tail is hydrophobic

what substances can pass through the phospholipid bilayer?

lipid-soluble substances

selectively permeable membrane def

only come materials can pass thru while others cannot

freely permeable membrane def

any substance can pass thru the membrane

impermeable membranes def

membranes where nothing can pass through

what is the permeability of the plasma membrane?

it is selectively permeable

what are all of the different ways that things enter and leave the cells?

• active processes

• passive transport processes

passive transport def

• a way that things enter and leave the cell

• do not require energy

• goes down the concentration gradient

  • high to low concentration

active processes def

• a way that things enter and leave the cell

• requires energy

what are the different types of passive transport?

• simple diffusion

• facilitated diffusion

• osmosis

• filtration

what happens during simple diffusion?

• particles move thru a selectively permeable membrane

• move from high solute concentration to low solute concentration

what are the factors that affect the rate of diffusion?

• distance

• molecule/gradient size

• temperature

what happens during facilitated diffusion?

molecules that are too big to it between phospholipids so carrier proteins ferrys them across the membrane

what happens during osmosis?

diffusion of water through a selectively permeable membrane from an area of higher water concentration

what impacts the osmotic flow?

• the difference in solute concentrations

  • the greater the difference, the higher the flow

osmolarity def

the solute concentration of the solution

what are the three effects of tonicity on the cell?

• isotonic

• hypertonic

• hypotonic

isotonic def

same concentration of solute in the solution and the cell

hypertonic def

• higher concentration of solute in the solution than in the cell

• solvent moves out of the cell causing crenation

  • moves where the concentr is higher

hypotonic def

• lower concentration of solute in the solution than in the cell

• solvent moves into the cell causing lyse

  • moves where the concentr is higher

what happens during filtration?

the bulk flow of substances because of pressure

• ex: blood pressure

what are the diff types of active processes?

• active transport

• secondary active transport

• vesicular transport

what happens during active transport?

• like facilitated diffusion, it uses carrier proteins

• needs ATP

• does not depend on any concentration gradient, works regardless

what happens during secondary active transport?

• moves sodium across the membrane to produce energy

• energy gets stored to pump glucose against the gradient

what happens during vesicular transport?

• macromolecules and fluids are pumped across the plasma membrane

exocytosis def

moving substances out of the cell

endocytosis def

moving fluids into the cell

all about the endoplasmic reticulum

• two types: rough and smooth

  • rough: has ribosomes, newly constructed proteins get modified and packed to the golgi apparatus

  • smooth: synthesizes phospholipids, detoxifies chemicals, synthesizes steroids/glycerides

all about the golgi apparatus

• in the shape of 5-6 flattened discs

• modifies, sorts and packages hormones and enzymes

• modifies the plasma membrane

• forms two vesicles: lysosomes + peroxisomes

all about the lysosomes

• a place that isolates dangerous chemical reactions

all about peroxisomes

• breaks down organic compounds

• neutralizes toxic compounds

all about the mitochondria

• provides energy for the cell in the form of ATP

  • process is called aerobic respiration

• has a double layered membrane

• has folded cristae, providing it with a large area to do ATP synthesis

all about the vacuole

• stores water, nutrients, or waste

all about the ribosomes

• free floating in the cytoplasm and attached to the rough ER

• site of protein synthesis

• makes proteins from amino acid building blocks and mRNA instructions

what are the names of the processes that make ATP?

• citric acid cycle

• electron transport

• glycolysis

what happens during the citric acid cycle?

• CO2 is removed from pyruvate

• the rest enters the cycle where the remaining pyruvate breaks down into carbon dioxide and hydrogen

• ATP is a bi product

what happens during glycolysis?

• glucose is broken down into two molecules of pyruvate

• happens in the cytoplasm

• reaction creates two molecules of ATP

what happens in the electron transport system?

• hydrogen atoms get delivered to enzymes and coenzymes of the cristae

• this catalyzes the synthesis of 32 molecules of ATP

all about the cytoskeleton

• acts as the cells skeleton and internal framework

• gives the cytoplasm strength and flexibility

all about the centrioles

• cylindrical structures made of microtubules

• helps with the movement of chromosomes during cell division

all about cilia

• long, hairlike fibers found on the cell’s surface

• help propel fluids and solids

all about microvili

• finger shaped extensions of the plasma membrane

• helps absorb nutrients from outside of the cell

all about the nucleus

• largest structure in the cell

• cellular control center

• stores all the nucleotides in the DNA

• controls protein synthesis

genes def

contain all the nucleotides needed to make a specific protein

RNA vs. DNA

• RNA = ribonucleic acid (has ribose)

  • single stranded

  • bases: A,G,C,U

  • three types: ribosomal, messenger, and transfer

• DNA - deoxyribonucleic acid

  • double helix shape

  • bases: A,G,C,T

  • found only in the nucleus of eukaryotic cells

what does rRNA do?

• combines with proteins to make ribosomes

• polypeptides get synthesized in the ribosomes

what does mRNA do?

• takes the coded DNA message to the cytoplasm and ribosomes

• builds polypeptides there

• code is written in codons

what does tRNA do?

• transfers amino acids to the ribosome

• adds to the polypeptide chain there

• uses anticodons to proofread

what are the two steps of for making proteins?

• transcription

• translation

what is transcription?

• DNA is a template for the creation of mRNA

• a gene is copied into mRNA

what is the enzyme that attaches to DNA and causes it to unzip?

helicase

what is translation?

• mRNA is read in the ribosome

• ribosome brings amino acids with help from tRNA

• amino acids get linked together to make a protein

what are the phase of the cell cycle

• interphase (the cell gets ready)

• mitosis (the cell divides)

• cytokinesis (the cell splits in two)

what happens during interphase?

• the cell grows, works, and prepares to divide

• three parts; G1, S, and G2

• G1: the cells grows, does normal functions, undergoes protein synthesis

• S phase: the cell replicated it's DNA

• G2 phase: makes sure its ready to divide by making necessary proteins

what are the three phases of interphase?

• G1

• S

• G2

what happens during mitosis?

• the nucleus divides, in steps

  • prophase: nuclear membrane breaks down, chromosomes become visible,

  • metaphase (middle): chromosomes line up in the middle of the cell

  • anaphase (apart): the chromosome copies get pullet to opposite ends of the cell

  • telophase: opposite of prophase

cytokinesis def

• the division of the cytoplasm

• its completion marks the end of cell division

what is the name of two new cells that are made?

daughter cells

all about daughter cells

have same number of chromosomes as the parent cell

what happens with cells for cancer and tumors?

there as an abnormal amount of cell growth and division

apoptosis def

• “cell suicide”

• cell genetic self destruction

tumor def

mass or swelling produced by abnormal cell growth and division

benign tumors def

the cells remain within the tissue of origin and do not spread to other tissues

malignant tumors def

• cells divide very rapidly

• releasing chemicals that simulate the growth of blood vessels into the area

• migrate into surrounding tissues and nearby blood vessels