Biology Ch.6

light microscope (LM)

visible light is passed through a specimen and then through glass lenses

magnification

the ratio of an object’s image size to its real size

resolution

the measure of the clarity of the image, or the minimum distance of two distinguishable points

contrast

visible differences in brightness between parts of the sample

organelles

the membrane-enclosed structures in eukaryotic cell.

electron microscopes (EMs)

What are used to study subcellular structures

scanning electron microscopes (SEMs)

focus a beam of electrons onto the surface of a specimen, \n providing images that look 3-D

transmission electron microscopes (TEMs)

focus a beam of electrons through a specimen and are used mainly to study the internal structure of cells

cell fractionation

takes cells apart and separates the major organelles \n from one another

reference it!

reference image on slide 6

cytosol

The semifluid substance in cells

nucleoid

DNA in an unbound region of a prokaryotic cell

cytoplasm

\

plasma membrane

is a selective barrier that allows sufficient passage of \n oxygen, nutrients, and waste to service the volume of every cell

metabolic requirements/ surface area to volume ratio

What sets upper limits on the size of cells? What ratio of a cell is critical?

its volume

As a cell increases in size, what grows proportionately more than its surface area

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reference image on slide 12

DNA/ the mitochondria and chloroplasts

The nucleus contains most of the what, in a eukaryotic cell. Where are some other genes located?

proteins

Ribosomes use the information from the DNA to make what?

nucleus

contains most of the cell’s genes and is \n usually the most conspicuous organelle

nuclear envelope

encloses the nucleus, separating it from the cytoplasm

reference it!

reference image on slide 14

the entry and exit of molecules from the nucleus

Pores, lined with a structure called a pore complex, regulate what?

nuclear lamina

The nuclear size of the envelope is lined by the what? This is composed of proteins and maintains the \n shape of the nucleus

chromosomes

In the nucleus, DNA is organized into discrete units called

chromatin

Each chromosome contains one DNA molecule associated with proteins, called

cells begin to divide

Chromatin condenses to form discrete chromosomes as what happens?

nucleolus

is located within the nucleus and is the site of ribosomal RNA (rRNA) synthesis

ribosomes

are complexes made of ribosomal RNA and protein

free ribosomes

Ribosomes carry out protein synthesis in the cytosol

bound ribosomes

Ribosomes carry out protein synthesis on the outside of the endoplasmic reticulum or the nuclear envelope

nuclear envelope, endoplasmic reticulum, golgi appratus, lysosomes, vacuoles, and the plasma membrane

The endomembrane system consists of what?

vesicles

The components of the endomembrane system are either continuous or connected via transfer by what?

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reference image on slide 17

endoplasmic reticulum (ER)

accounts for more than half of the total \n membrane in many eukaryotic cells

smooth ER

ER that lacks ribosomes

rough ER

ER whose surface is studded with ribosomes

synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions

What are the 4 functions of smooth ER?

glycoproteins

proteins covalently bonded to carbohydrates

Has bound ribosomes which secrete glycoproteins, distributes transport vesicles, and is a membrane factory for the cell.

What are the three functions of rough ER?

transport vesicles

secretory proteins surrounded by the membranes

golgi apparatus

consists of flattened membranous sacs called cisternae

modifies products of the ER, manufactures certain macromolecules, and it sorts and packages materials into transport vesicles

what are the three functions of the golgi apparatus?

reference it!

reference image on slide 21

lysosomes

is a membranous sac of hydrolytic enzymes that can digest \n macromolecules

phagocytosis

some types of cells can engulf another cell by what? This forms a food vacuole.

autophagy

Lysosomes also use enzymes to recycle the cell’s own organelles and macromolecules, a process called

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reference image on slide 22

vacuoles

are large vesicles derived from the ER and Golgi \n apparatus

food vacuoles

are formed by phagocytosis

contractile vacuoles

found in many freshwater protists, pump excess water out of cells

central vacuoles

found in many mature plant cells, hold organic compounds and water

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reference image on slide 24

mitochondria

are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP

chloroplasts

found in plants and algae, are the sites of photosynthesis

peroxisomes

are oxidative organelles

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reference image on slide 25

enveloped by a double membrane, contain free ribosomes, and circular DNA molecules, and grow and reproduce somewhat independently/ endosymbiont theory

What are the three similarities that mitochondria and chloroplasts have with bacteria? These similarities led to what theory?

mitochondria/ a chloroplast

In the endosymbiont theory the engulfed cell formed a relationship with the host cell, becoming an endosymbiont, the endosymbionts eventually evolved into what? At least one of these cells may have taken up a photosynthetic prokaryote, which evolved into what?

cristae/ reference it!

Mitochondria have a smooth outer membrane and an inner membrane folded into what? reference image 28

mitochondrial matrix

contains many different enzymes as well as the mitochondrial DNA and ribosomes. enzymes can also catalyze some of the steps in cellular respiration

synthesize ATP

cristae present a large surface area for enzymes that do what?

chlorophyll/ reference it!

Chloroplasts contain the green pigment called what, as well as enzymes and other molecules that function in photosynthesis/ reference image on slide 29

thylakoids/ a granum

membranous sacs in chloroplast structure/ membranous sacs stacked to form what

plastids

the chloroplast is one of a group of plant organelles called what?

peroxisomes/ hydrogen peroxide and then convert it to water

are specialized metabolic compartments bounded by a single membrane. They produce what and then convert it to what?

cytoskeleton/ microtubules, microfilaments, and intermediate filaments

is a network of fibers extending throughout the cytoplasm/ it is composed of what three types of molecular structures?

structures and activities/ many organelles

the cytoskeleton organizes the cell’s what? It anchors what?

motor proteins/ tracks provided by the cytoskeleton

the cyctoskeleton interacts with what, in order to produce cell motilty? inside the cell, vesicles can travel along what?

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reference image on slide 33

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reference image on slide 35

shaping the cell, guiding movement of organelles, and separating chromosomes during cell division

the three functions of microtubules are what?

centrosome

In animal cells, microtubules grow out from a what near the nucleus?

centrioles

in animal cells, the centrosome has a pair of what, each with nine triplets of microtubules arranged in a ring?

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reference image on slide 37

flagella and cilia

microtubule-containing extensions that project from some cells

cilia or flagella

many unicellular eukaryotes are propelled through water by what?

their beating patterns/ reference it!

What do cilia and flagella differ in? reference image on slide 38

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reference image on slide 39

basal body

this anchors the cilium or flagellum

dynein

A motor protein which drives the bending movements of a cilium or flagellum

bend/ because microtubules are held in place

dynein has two “feet” that “walk along microtubules. one foot maintains contact, while the other releases and reattaches one step farther along. movements of the feet cause the microtubules to do what rather than slide? This is because why?

microfilaments

are solid rods about 7 nm in diameter, built as a twisted double chain of actin subunits

cortex

microfilaments form this just inside the plasma membrane to help support the cell’s shape

microfilaments

are solid rods about 7nm in diameter, built as a twisted double chain of actin subunits

actin

a globular protein that is built in microfilaments

cortex

the outer cytoplasmic layer of a cell that is inside the plasma membrane to help support the cell’s shape microfilaments form this

myosin

microfilaments that function in cellular motility contain this protein in addition to actin

pseudopodia (cellular extensions)

cells crawl along a surface by extending this and moving toward them.

cytoplasmic streaming

is a circular flow of cytoplasm within cells, driven by actin-myosin interactions

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reference image on slide 42

intermediate filaments

range in diameter from 8 to 12 nanometers, larger than microfilaments but smaller than microtubules

cell wall

is an extracellular structure that distinguishes plant cells from animal cells

primary cell wall

the layer of the plant cell wall that is relatively then and flexible

middle lamella

the layer of the plant cell wall that is a thin layer between primary walls and adjacent walls

secondary cell wall

the layer of the plant cell wall (in some cells) that is added between the plasma membrane and the primary cell wall

reference it!

reference image on slide 46

extracellular matrix (ECM)/ collagen, proteoglycans, and fibronectin

animal cells lack cell walls but are covered by an elaborate what? it is made up of three glycoproteins that are?

collagen

forms strong fibers outside the cell

proteoglycans

consists of a small core protein with many carbohydrate chains covalently attached, so that it may be up to 95% carbohydrate.