AP Bio - Unit 2: Cell Structure and Function

eukaryote

linear chromosomes within a membrane-bound nucleus

has membrane-bound organelles

often multicellular

plants, animals, protists, fungi

prokaryote

circular chromosomes found in cytosol

single-celled with cell walls

no membrane-bound organelles

bacteria, archea

nucleoid

contains genetic material of prokaryotic cell

endosymbiosis

mitochondria and chloroplasts originated as separate bacteria organisms and were engulfed but not digested by an ancestral eukaryote and a symbiotic relationship was developed

EVIDENCE: they divide and replicate individually, and it is similar to bacteria

single circular chromosomes like prokaryotes

protein-synthesizing ribosomes that resemble ones found in prokaryotes

they have double membranes, the inner one resembles prokaryotes

similar size and shape as prokaryotes

plasma membrane

selective barrier around cell composed of a double layer of phospholipids

cytoplasm

place for cell reactions between the membrane and the nucleus (for eukaryotes) and contains all organelles in prokaryotes

cytosol

semifluid substance in cytoplasm

organelle

a structure within a cell

nucleus

contains the DNA in eukaryote

nuclear envelope

encloses the nucleus, separating genetic material from cytoplasm

nucleolus

region in nucleus where ribosomes are assembled

ribosome

site of protein synthesis (secretion, insertion into cell membrane)

protein synthesis

cells create proteins

the endomembrane system

system containing organelles with membranes around them

vesicles

small membrane-bound sacs that move chemicals in and out of the cell

smooth endoplasmic reticulum

lipid synthesis, detoxification, and carbohydrate metabolism

rough endoplasmic reticulum

produces proteins to be carried to golgi by vesicles

golgi complex

receives proteins via vesicles from rough ER, modifies those proteins, and places them within another vesicle to route them to their final destination

cisternae

key component of rough ER and golgi

lysosome

digestion (breaks down macros) and programs cell death

apoptosis

programmed cell death

vacuole

intracellular digestion and the release of cellular waste products

central vacuole

stores water to maintain turgor pressure in plant cells, can also store nutrient

tonoplast

the semipermeable membrane that surrounds the large central vacuole in plant cells

contractile vacuole

found in only freshwater proteins and maintains water balance by pumping out excess water

mitochondria

site of cell respiration (uses oxygen to breakdown organic compounds and produce ATP)

cristae

folds of inner mitochondrial membrane that allow for more surface area thus more cell respiration

chloroplast

performs photosynthesis and energy production in plants

photosynthesis

light converted into energy for plants

peroxisomes

performs metabolic functions and detox in eukaryotes

cytoskeleton

provides support, shape, and mobility to cells

centrosomes

microtubule organizing centers that form the mitotic spindle in dividing cells

centrioles

involved in cell division and formation of cilia and flagella in eukaryotes

cell wall

wall or barrier in prokaryotes for shape and protection

flagella

tail-like projection powered by motor proteins, involved in cell movement

cilia

short finger-like projections powered by motor proteins, cell movement

pseudopod

temporary arm-like cellular extension, cell movement and ingestion

intracellular junction

channels between two cells that allow water and solute to pass between them

plasmodesmata

cannel in cell wall connecting 2 plant cells

tight junctions

cell-to-cell connections that create a semi-permeable layer

desmosomes

anchors adjacent cells together to maintain the mechanical integrity of tissues

gap junctions

channel in cell wall connecting 2 animal cells

phospholipids

creates semi-permeable layer, hydrophilic heads and hydrophobic tails

cholesterol

steroid that stabilizes the fluidity of the cell membrane

aquaporin

water moves rapidly in and out of cell

peripheral protein

membrane proteins that are loosely attached to the surface of the cell membrane

integral protein

proteins that are permanently embedded in the cell membrane

glycoproteins

protein bonded to carb chain, plays key role in cell recognition

glycolipids

lipid bonded to carb chain, plays key role in the cell recognition

passive transport

molecule moves down concentration gradient without energy (simple diffusion, facilitated diffusion, osmosis)

2nd law of thermodynamics

universe tends towards disorder / entropy

simple diffusion

molecules that can naturally cross the membrane wwithout help

facilitated diffusion

molecules cross the membrane with the help of a transport protein

gated channel

stimulus causes gate to open orclose (transport protein with a gate)

active transport

moving a molecule against its concentration gradient and requiring energy

membrane potential

difference in charge across the membrane (voltage)

sodium potassium pump

move sodium and potassium against their conc gradients, requires breakdown of ATP, generates electrochemical gradient, inside more negative

electrochemical gradient

ions move down the conc gradient based on chemical and electric force

cotransport

coupling one molecule moving down its gradient with another moving against

exocytosis

cellular secretion of macromolecules through the fusion of vesicles with the plasma membrane

endocytosis

cellular uptake of molecules by a region of the plasma membrane surrounding the substance and pinching off to form an intracellular vesicle

phagocytosis

cellular uptake of a large substance or small organism via a vesicle

pinocytosis

cellular intake of extracellular fluids and its dissolved solutes

receptor-mediated endocytosis

movement of specific molecules into cell by the inward budding of membraneous vesicles containing proteins with receptor sites specific to the molecules being taken in

ligand

molecule that binds specifically to a receptor site of another molecule

osmosis

diffusion (passive transport) of water across a selectively permeable membrane

tonicity

a measure of the relative solute concentration of a solution compared to another

hypertonic

more solute less water compared to other

hypotonic

more water less solute compared to other

isotonic

no net movement of water, equilib

plasmolysis

cell membrane pulls away from cell wall

cell lysis

cell bursts open

water potential

physical property predicting which way water will flow

turgor pressure

force directed against a cell wall after the influx of water and the swelling of a walled cell due to osmosis

solute potential

represents the effects of dissolved solutes on the solution

pressure potential

pressure in addition to atm

turgid

entry of water, walled cell has greater solute conc than surrounding hypotonic

flaccid

limp, walled cell placed into isotonic

molarity

concentration

homeostasis

steady state maintained by negative feedback

interstitial fluid

conformer

internal conditions match external

regulator

maintain relatively constant internal conditions

osmoregulation

maintaining a certain osmolarity in a solution through negative feedback

osmolarity

measure of the concentration of solute particles in a solution that contribute to osmotic pressure

nitrogenous wastes (metabolic wastes)

must be excreted out by kidneys

excretory system

a collection of organs that removes metabolic waste, excess water, and other by-products from the body

kidney

major excretory organs of vertebraes

excretion

disposal of nitrogen-containing waste

negative feedback

mechanism for homeostasis, change in set point triggers a response that counteracts the change

effector

muscle/gland that receives signals from control center and corrects deviation

endocrine gland

glands that secrete hormones to bloodstream for homeostasis

hormone

chemical messengers that maintain homeostasis

ADH

increases reabsorption of water in the kidneys