AP Biology 2022-23 - Campbell Biology Unit 1 Chapter 6 Flashcards

What is resolving power and why is it important in biology?

The ability of a microscope to clearly distinguish between two plants.

How does an electron microscope work and what is the difference between a scanning (SEM) and transmission (TEM) electron microscope?

SEM - focuses on beams of electrons (e-) onto the surface of a specimen—looks 3D
TEM - Focuses on beams of electrons (e-) through a specimen (cannot be alive) - shows internal detail

(Prokaryotic Cell) Bacterial chromosome

"The bacterial chromosome is one long, single molecule of double stranded, helical, supercoiled DNA" - https://bio.libretexts.org

(Prokaryotic Cell) Fimbriae

attachment structures on the surface of *some* prokaryotes

(Prokaryotic Cell) Nucleoid

region where the cell's DNA is located (not enclosed by a membrane)

(Prokaryotic Cell) Ribosomes

complexes that synthesize proteins

(Prokaryotic Cell) Plasma Membrane

membrane enclosing the cytoplasm

(Prokaryotic Cell) Cell Wall

rigid structure outside the plasma structure

(Prokaryotic Cell) Capsule

jelly-like outer coating of many prokaryotes

(Prokaryotic Cell) Flagella

locomotion organelles of some bacteria

Why is surface area to volume such an important concept as it applies to the size of a cell?

As SA:V ratio decreases diffusion slows down and becomes less efficient—the ratio goes down as the cell grows

How can some organelle depict evolutionary origins?

Endosymbiotic Theory - hypothesizes that some of the organelles in eukaryotic cells were once prokaryotic microbes.
Mitochondria and chloroplasts are the same size as prokaryotic cells and divide by binary fission.
Mitochondria and chloroplasts have their own DNA which is circular, not linear.

(Nucleus) Nuclear Envelope

houses chromosomes, contains nucleoli, has pores that regulate entry/exit of proteins and RNA, has a double membrane

(Nucleus) Nuclear Lamina

mechanically supports nuclear envelope, thus maintaining shape of the nucleus; has net-like array of protein filaments (in animal cells, these protein filaments are called intermediate filaments)

(Nucleus) Chromosomes

consist of coiled up discrete units of DNA—long DNA molecule + many proteins

(Nucleus) Chromatin

complex of uncoiled, long strands of DNA and proteins that make up chromosomes; is usually diffuse but condenses during cell division

(Nucleus) Nucleolus

site of ribosomal (rRNA) synthesis (with proteins), adjoins part of chromatin, made of densely-strained granules and fibers

Ribosomes

assemble site of protein synthesis, made of rRNA + proteins; translates mRNA "messages" to create the *primary structures* of proteins
"While both types of ribosomes are used to make proteins, the difference between them has to do with the fate of the proteins. Cytosolic ribosomes make proteins for the cytosol, which rough endoplasmic reticulum ribosomes make them to be bound in membranes, or to be excreted from the cell in vesicles (exocytosis)." - varsitytutors.com

Smooth Endoplasmic Reticulum

LACKS RIBOSOMES, synthesizes lipids, metabolizes carbohydrates, detoxifies drugs/toxins, stores Calcium (Ca+) ions

Rough Endoplasmic Reticulum

HAS RIBOSOMES, secretes glycoproteins (proteins with carbohydrates covalently-bonded to them, hence the prefix), distributes transport vesicles, creates membranes for itself or other components of the endomembrane system
has membrane that separates glycoproteins from the cytosol

Golgi Complex/Apparatus

modifies, stores, and sends products (proteins and phospholipids) of the ER; makes its own macromolecules; sorts and packages material into transport vesicles

Lysosomes

digest macromolecules through membrane sacs with hydrolytic enzymes, recycles organelles (autophagy), carries out apoptosis with mitochondria, performs phagocytosis

Apoptosis

"Apoptosis is the process of programmed cell death" - genome.gov

Phagocytosis

"Amoebas and many other unicellular eukaryotes eat by engulfing smaller organisms or food particles" - Campbell Biology

Vacuoles (General)

large vesicles from ER & golgi complex/apparatus

Food Vacuoles

formed through phagocytosis, fuse with lysosomes

Contractile Vacuoles

found predominentaly in protists and unicellular algae that live in freshwater; osmoregulate (pump out excess water)

Central Vacuole w/Tonoplast

(in plant cells) membrane that separates vacuole from cytoplasm, holds water (turgor pressure) and organic compounds,

(Central Vacuole) Cell Sap

"The solution inside the central vacuole that is the plant cell’s main repository of inorganic ions, including potassium and chloride." - Campbell Biology

Endomembrane System

group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins

The Endomembrane System includes:

nuclear membrane, smooth & rough ER, golgi apparatus, lysosomes, various vesicles/vacuoles, cell/plasma membrane

Mitochondria

site of cellular respiration (for energy production)

(Mitochondria) Mitochondrial Matrix

gel-like material where the citric acid cycle occurs, included by inner membrane
contains enzymes, mitochondrial DNA + ribosomes
dynamic state of flux AKA can move and adjust a lot to meet needs of cell

(Mitochondria) Cristae

folds of inner membrane that provide large amount of surface area for chemical reactions to occur

Plastids

a family of plant organelles that DO NOT EXIST IN ANIMAL CELLS

(Plastids) Amyloplast

plastids that produce and store starch in plants; (colorless)

(Plastids) Chromoplast

colored plastids (OTHER THAN CHLOROPLASTS) typically containing yellow (lutein) and green (carotene) pigment

(Plastids) Chloroplast

photosynthesis—contains chlorophyll

(Chloroplast) Thylakoid

interconnected, flattened sacs with chlorophyll where light reactions take place
Granum - stacked thylakoids

(Chloroplast) Stroma

colorless fluid surrounding grana (stacked thylakoids) within chloroplast where "dark" reactions take place; contains chloroplast DNA + ribosomes + enzymes

Peroxisome

metabolic compartment w/ single membrane (it is a membrane-bound organelle; has enzymes that remove hydrogen atoms from substrates and then add oxygen atoms to form hydrogen peroxide (H2O2)—THIS IS THEIR NAMESAKE; breaks down fatty acids into smaller molecules for mitochondria (and therefore cellular respiration)

(Peroxisome) Glyoxysome

(in certain fat-storing tissues of plant seeds) specialized peroxisomes that convert fatty acids into sugar

Cytoskeleton (General)

fiber network throughout cytoplasm
mechanical support, maintains shape
anchors organelles + enzymes
easily reassemble-able
cell motility (movement) w/ help of motor proteins
manipulates cell (plasma) membrane

(Cytoskeleton) Microtubules

hollow tubes (made of tubulin, or globular proteins) maintain shape of cell, movement of organelles & chromosomes
guides vesicles
separates chromosomes during cell division

(Microtubules) Centrosomes & Centrioles

help organize microtubule assembly
Centrioles - 9 sets of triplet microtubules in ring arrangement that come in pairs
PLANT CELLS LACK BOTH CENTROSOMES AND CENTRIOLES

(Microtubules) Cilia and Flagella

microtubule-containing extensions on some cells for locomotion of cell itself or move substances across cell
cilia move like oars, flagella move w/ single undulations (think ocean snakes)
both are anchored to cell by basal bodies
cilia come in large numbers VS flagella single or in small numbers
most animals cells a primary cilium with an "antenna" function instead of locomotion

(Microtubules) Dynein Walking

motor proteins that cause microtubules to move and allow organelles or cells to bend

Microfilaments

thin, solid rods made of twiste actin double chains; bears tension

(Microfilaments) Actin

globular proteins where microfilaments are formed

(Microfilaments) Cortex

outer cytoplasmic layer of a cell; has semi-solid consistency (like gel) due to the network of microfilaments

(Microfilaments) Pseudopodia

"false foot" actin and myosin work together to cause movement
"The cell crawls along a surface by extending cellular extensions called pseudopodia and moving toward them" - Campbell Biology

(Microfilaments) Cytoplasmic Streaming

actin proteins allowing for movement of cytoplasm in a circular flow within large plant cells
facilitates movement of organelles + materials within cell

Intermediate Filament

in terms of size, microfilaments < intermediate filaments < microtubules
ONLY FOUND IN ANIMAL CELLS, bears tension
is more "permanent" i.e. is not deconstructed and reconstructed as much
cages the nucleus (mentioned in nuclear lamina flashcard)

Cell Wall (General)

extracellular structure of PLANT CELLS
protects, maintains shape, prevents excess water
(some other organisms have cell walls but not animals)

(Cell Wall) Primary Cell Wall

young, thin, flexible cell wall

(Cell Wall) Middle Lamella

pectin (a sticky polysaccharide) layer between adjacent cells, essentially a "glue"

(Cell Wall) Secondary Cell Wall

strong, double matrix that adds support to the primary cell wall
NOT ALL PLANT CELL HAVE SECONDARY CELL WALLS

Extracellular Matrix (ECM) (General)

glycoproteins + other carbohydrate-containing molecules

(ECM) Collagen

most abundant glycoprotein; forms strong, long fibers outside cells—strengthens tissues and adds structural integrity

(ECM) Proteoglycans

made up with carbohydrates (95%), interwoven with collagen fibers

(ECM) Fibronectin

an ECM glycoprotein that acts as bridges between integrins and other ECM glycoprotein (such as collagen)

(ECM) Integrin

receptor proteins embedded in cell/plasma membrane
"integrins are in a position to transmit signals between the
ECM and the cytoskeleton and thus to integrate changes
occurring outside and inside the cell" - Campbell Biology

What are intercellular junctions and why are they important?

Interactions that enable communication, interaction, or adhesion between cells

Plasmodesmata

DO NOT EXIST IN ANIMAL CELLS
channels between adjacent plant cells (enable exchange between cells)

Gap Junction

DO NOT EXIST IN PLANT CELLS
channels between adjacent animal cells (enable exchange between) cells

Tight Junction

DO NOT EXIST IN PLANT CELLS
watertight (all fluid-tight) seal between two adjacent animal cells

Desmosome

DO NOT EXIST IN PLANT CELLS
acts like a spot weld to ensure that cells in stretchy organs and tissues (e.g. skin, cardiac muscle) remained connected in unbroken sheets

Contrast plasmodesmata, tight junctions, desmosomes, and gap junctions

"Plasmodesmata are channels between adjacent plant cells (allowing for exchange between cells), while gap junctions are channels between adjacent animal cells (allowing transport of ions, water and other substances). A tight junction is a watertight seal between two adjacent animal cells, while a desmosome acts like a spot weld ensuring that cells in organs and tissues that stretch, such as skin and cardiac muscle, remain connected in an unbroken sheet."

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