Section 2: Cells Flashcards by michael perna

These membrane proteins are loosely attached to one side/surface of the membrane

Peripheral membrane proteins

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This type of membrane protein embeds inside membranes

Integral membrane proteins

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This type of membrane proteins goes all the way through the membrane, it’s on both sides of the membrane

Transmembrane integral proteins

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What type of molecules can freely pass across the membrane?

Everything else requires…

Small, uncharged, nonpolar molecules

Transport proteins

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PERIPHERAL membrane proteins are generally HYDROPHILIC/HYDROPHOBIC

What holds them in place?

How can they be disrupted or detached?

hydrophilic

H-bonding, electrostatic interaction

Changing salt concentration or pH

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Integral membrane proteins are generally HYDROPHILIC/HYDROPHOBIC?

What can destroy and expose them?

Hydrophobic

Detergent

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In cells, these proteins provide passageway through membrane for hydrophilic (water-soluble) substances (polar, and charged

Channel Proteins

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These proteins distinguish between self and foreign

What type of molecule are they? What is attached to them?

What is an example of a recognition protein on macrophages?

Recognition proteins

glycoproteins

Oligosaccharides

Major-histocompatibility complex (MHC)

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These proteins allow the passage of ions across the cell membrane that respond to stimuli.

What are they called in nerve and muscle cells?

Ion channels

Gated channels

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These are ion channels that respond to differences in membrane potential

Voltage gated ion channels

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These are ion channels where a chemical binds and opens the channel

Ligand gated ion channels

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These are ion channels that respond to pressure, vibration, or temperature differences

Mechanically gated ion channels

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In cells, these proteins allow the passage of certains ions + small polar molecules

Do they tend to be specific or unspecific?

Porins

Specific. If you can’t fit you don’t go through

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This type of porin increases the rate of H2O passing in kidney and plant root cells.

Aquaporin

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These proteins bind to specific molecules, causing a shape change in the proteins (still bound to the molecule) so that the molecule can pass across.

They seem to be specific to movement across membrane via ____________

Ex: glucose going into the cell.

Carrier Proteins

Integral membrane proteins

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Some of these proteins use ATP to transport materials across the cell membrane. Not all do however.

Transport proteins

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Transport proteins that use ATP employ this type of transport

What is an example of active transport in cells?

What type of transport is it when transport proteins don’t use active transport

Active Transport

Na+ and K+ pump to maintain the electrochemical gradient

Facilitated diffusion

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These proteins attach to neighboring cells and provide anchors for internal filaments and tubules which provide stability

Adhesion proteins

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These proteins are the binding site for hormones and other trigger molecules

Receptor proteins

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This lipid molecule of the cell adds rigidity to the membrane of animal cells under normal conditions, but at a low temperature maintains its fluidity

What is the similar molecule in plants?

Cholesterol

Sterols

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Do prokaryotes have cholesterol in their membranes?

What do they have?

No.

Hopanoids

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This is a carbohydrate coating that covers the outer face of the cell wall of some bacteria and the outer face of the plasma membrane.

What is it made of?

What does it provide?

Glyocalyx

Glycolipids (attached to plasma membrane) and glycoproteins (like recognition proteins)

Barrier to adhesive capabilities of pathogens or markers for cell recognition

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This organelle contains chromatin, chromosome, histones, nucleosomes, etc.

Nucleus

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This is the name for DNA when it is not condensed

Chromatin

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This is the term for condensed chromatin when the cell is ready to divide

Chromosome

These proteins organize DNA which coils around them to into bundle nucleosomes

Histones

This is the basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound in sequence around eight histone protein core

nucleosome

These are found inside the nucleus and are the maker of ribosomes, aka.....

Nucleolus, makes ribosomes AKA rRNA

rRNA synthesized in the nucleolus + ribsomal proteins imported from the cytoplasm =?

Ribosomal subunits

After ribosomal subunits form in the nucleolus, where are they exported for final assembly into a complete ribosome?

The cytoplasm

The nucleus is bound by a SINGLE/DOUBLE layer nuclear envelope

Double layer

What are in the nuclear envelope which allow for transport? What transports out of them?

Nuclear Pores mRNA, ribosome subunits, dNTPs, proteins like RNA polyermase, histones, etc.

Is there a cytoplasm in the nucleus? What is the term then for the similar area in the nucleus?

No Nucleoplasm

This is a dense fibrillar network inside the nucleus of ______ cells made of intermediate filaments and membrane associated proteins. It provides mechanical support and helps regulate DNA replication cell division, and chromatin organization

Nuclear Lamina, Eukaryotic cells

This in an irregular shaped region within the cell of a PROKARYOTE that contains almost all genetic material

Nucleoid (similar to nucleus in eukaryotes)

Is the nucleoid membrane bound?

No, by the nucleus in eukaryotic cells is

Metabolic activity and transport occur here. It doesn't include the nucleus but does include cytosol, organelles, everything suspended within it except the nucleus

Cytoplasm (NOT a structure, just an area)

This is the term for streaming movement within the cell in the cytoplasm

Cyclosis

The are made of RNA + protein, they function to make proteins

Ribosomes

These cells have a 60S + 40S = 80S ribsome

Eukaryotes

These cells have a 50S + 30S = 70S ribosome

Prokaryotes

In ribosome formation, the two subunits produced inside the nucleolus move into the cytosplasm where they are assembled into ___S ribosomes (EUKARYOTES)

80S

This creates glycoproteins by attaching polysaccharides to polypeptides as they are assmebled by ribosomes

Rough Endoplasmic Reticulum

In eukaryotes, the rough ER is continuous with the...

Outer membrane

This organelle synthesizes lipids and steroid hormones for export

Smooth Endoplasmic Reticulum (no ribosomes)

In liver cells, the __________ has functions in breakdown of toxins, drugs, and toxic by products from cellular reactions. It can also store ions

Smooth ER

These are vesicles that contain digestive enzymes, functioning in apoptosis by releasing its contents into the cell

Lysosomes

Where are lysosomes produced? The digestive enzymes within them require a LOW/HIGH pH?

The Golgi apparatus low pH, so they any that escape remain inactive in the neutral pH of the cytosol.

Are there lysosomes in the plant cell?

Maybe. But generally thought of as none.

These organelles break down substances like fatty acids, and amino acids. It can create or break down hydrogen peroxide. Where are they common in mammals, where they break down toxins?

Peroxisomes Common in the liver and kidney

This is the term for the cytoplasm without the organelles, it's the jell-O like substance

Cytosol

What function do peroxisomes have in plant cells?

They modify by-products of photorespiration

What are the peroxisome like structures in germinating seeds which break down stored fatty acids to help generate energy for growth?

Glyoxysomes

This substance can be produced by peroxisomes which can be used to oxidize substrates. It can also be broken down by peroxisomes

Hydrogen peroxide

These provide support and motility for cellular activities, they are the spindle apparatus which guide chromosomes during cell division.

Microtubules

What do microtubules compose, other than the spindle apparatus which guides chromosomes? What protein are microtubules composed of?

Flagella and cilia Tubulin

These provide support for maintaining cell shape

Intermiediate filaments

These are made up of actin and are involved in cell motility, like in skeletal muscle amoeba pseudopod, cleavage furrow

Microfilatments

These are made of microtubules, 9+2 array, 9 pairs + 2 singlets in center

Flagella and cilia

These include centrioles and basal bodies, is a structure found in eukaryotic cells from which microtubules emerge. 9x3 array

Microtubule organizing centers

These have two main functions: the organization of eukaryotic flagella and cilia and the organization of the mitotic and meiotic spindle apparatus, which separate the chromosomes during cell division.

Microtubule organizing center

These are MTOCS that are at the base of each flagellum and cilium and organize their development, are a 9x3 array

Centrosomes and basal bodies

Plant cells lack centrioles because its division is by _______ instead of cleavage furrow – note that plants DO have MTOC’s

Cell plate

These move materials between organelles or between organelles and the plasma membrane

Tranport vacuoles

These are temporary recepticles of nutrients, they merge with lysosomes which break down food

Food vacuoles

There are large and occupy most of the plant cell interior. They exert turgor when fully filled to maintain rigidity

Central vacuoles

In addition to maintaining turgidity, these also store nutrients, and carry out functions performed by _____ in animal cells

Central vacuoles Lysosomes

What is the name for the specialized membrane of central vacuoles?

Tonoplast

These are in plants and store starch, pigments, and toxic substances like nicotene

Storage vacuoles

These are in single celled organisms, they collect and pump excess water out of the cells to prevent bursting What type of transport is it? In what organisms are they found? Are they in hypertonic or hypotonic environment

Contractile vacuoles Active Transport Protista (ameoba, paramecia) Hypotonic (less concentration of solutes inside the cell, hence these push water out of the cell to maintain hypotonicity)

Cell walls are found in these 4 organisms

Plants, fungi, protists, and bacteria

This forms the cell wall in plants This forms it in fungi This forms it in bacteria This forms it in archea

Cellulose Chitin peptidoglycan polysaccharides

This structure provides support in plants, fungi, protists, and bacteria. Sometimes a secondary one develop beneath the primary one

Cell wall

This is found in animals in the area between adjacent cells beyond the plasma membrane and glycocalyx. It provides mechanical support and helps bind adjacent cells

Extracellular matrix

What occupies the extracellular matrix? What is most abundant protein in the extracellular matrix?

Fibrous structural proteins, adhesion proteins, and polysaccharides secreted by cells Collagen Integrin and fibronectin are also seen

These are found in plant cells, include chloroplasts, leucoplasts, and chromoplasts

Plastids

These are the site of photosynthesis in plant cells

Chloroplasts

These plastids store starch in plant cells

Leucoplasts

These plastids store carotenoids in plant cells

Chromoplasts

This is the site of ATP production, What else does it perform?

Mitochondria Fatty acid catabolism (β-oxidation)

Where are fatty acids made?

Cytosol

The mitochondira has its own ________ and _________ and a SINGLE/DOUBLE layered membrane

Circular DNA Ribosomes

Mitchondria give rise to what theory base upon having its own circular DNA and ribosome?

Endosymbiotic theory

This structure is made of microtubules (cilia and flagella), microfilaments, intermediate filaments. In eukaryotic cells it aids in cell division, cell crawling, and the movement of the cytoplasm and organelles

Cytoskeleton

Is the normal state of plant cells hypertonic or hypotonic?

Hypotonic

In plant cells, the vacuole swells in hypotonic solution leading to... In an isotonic solution, the cell is In a hypertonic solution, the cell is

turgidity Flaccid Plasmolyzed

This occurs in hypertonic solutions in plant cells, the cytoplasm is pulled away from the cell wall

Plasmolyzed

Fungal, in addition to plant cells, will remain turgid in hypertonic solutions due to ______ In an animal cell, it will undergo

Cell walls Cytolysis (bursting)

This is the network of organelles and structures, either directly or indirectly connected, that function in the transport of proteins and other macromolecules into or out of the cell.

Endomembrane system

What organelles comprise the endomembrane system?

Plasma membrane, endoplasmic reticulum, golgi apparatus, nuclear envelope, lysosomes, vacuoles, vesicles, endosomes but not the mitochondria or chloroplasts

In this category of circulation, Brownian movement, cyclosis, and movement through the ER occur

Intracellular Circulation

In intracellular circulation, this type of movement occurs when particles move due to kinetic energy, it spreads small suspended particles throughout the cytoplasm

Brownian Movement

This type of intracellular circulation is the circular motion of the cytoplasm around cell transport molecules

Cyclosis/Streaming

In intracellular circulation, this structure provides a channel through the cytoplasm and provides a direct and continuous pathway from the plasma membrane to the nuclear membrane

Endoplasmic Reticulum

What are the two categories of extracellular circulation?

Diffusion and the circulatory system

In extracellular circulation, this occurs when cells in close contact with external environment can suffice for food and respiration needs. It is also used for the transport of materials between cells and interstatial fluid around cells in more complex animals

Diffusion

This type of extracellular circulation occurs in complex animals with cells too far from the external environment, it uses vessels

Circulatory System

These are keratin filaments inside cells, they attach to adhesion plaques that bind adjacent cells together. They are found in tissues with mechanical stress They are found in PLANT/ANIMAL cells

Desmosomes Skin epithelium, cervix/uterus are where they are commonly found Animals

Desmosomes form _____ between cells

Tight Junctions

These completely encircle each cell, producing a seal that prevents the passage of materials BETWEEN cells

Tight Junctions

Tight junctions are characteristic of cell lining the _______ where materials are required to pass through cells into blood.

Digestive tract.

These force all materials to enter cells, keeping ions and molecules out of the space between the cells What two ways can molecules enter the cells?

Tight junctions Active Transport of Diffusion

Tight junctions are found in PLANT/ANIMALS cells

Animal cells

These are narrow tunnels between animal cells (connexins), they prevent the cytoplasms of each cell from mixing but allow the passage of ions and small molecules.

Gap Junctions

These are essentially channel proteins of two adjacent cells that are closely aligned, tissues like heart have these to pass electrical impulses

Gap Junctions

These are narrow tunnels between plant cells

Plasmodesmata

This category of organisms includes all organisms except for bacteria, cyanobacteria, and archaebacteria

Eukaryotes

EUKARYOTES/PROKARYOTES have a plasma membrane

Prokaryotes

Do prokaryotes have a ribosome?

Yes

Do prokaryotes have DNA?

yes, a single circular DNA molecule

Do prokaryotes have a cell wall?

Yes, not eukaryotes

Do prokaryotes have a nucleus?

No, nucleoid

What is the composition of the ribosome of prokaryotes?

50S +30S = 70S

Are flagella constructed from microtubules in prokaryotes?

No.

This is defined as higher solute concentration within cells than the surrounding environment

Hypertonic

This is defined as a lower solute concentration within cells than the surrounding environment

Hypotonic

This is defined as equal solute concentration within the cell and outside the environment

Isotonic

This is the collective movement of substances in the same direction in response to a force or pressure

Bulk Flow

Simple diffusion, osmosis, dialysis, plasmolysis, facilitated diffusion, countercurrent exchange are all what type of transport?

Passive transport

This type of passive transport is defined as the diffusion of different solutes across a selectively permeable membrane

Dialysis

This type of passive transport is defined as the movement of water out of a cell that results in its collapse

Plasmolysiis

This type of passive transport is defined as diffusion by bulk flow in opposite directions; like blood and water in fish gills

Countercurrent Exchange

Do all particles move with the gradient in diffusion?

No, we speak of net diffusion. Some particles still move against the gradient

This type of transport is the movement of particles against their concentration gradient that requires energy. It is usually SOLUTES like small ions, amino acids, and monosaccharides

Active transport

This is cytosis that uses ATP

Endocytosis

This is cytosis in which undissolved material (solid) enter a cell, the white blood cell engulfs. The plasma membrane wraps outward around it.

Phagocytosis

This is cytosis of dissolved material (liquid), the plasma membrane invaginates (infolds)

Pinocytosis (like formation of endosome)

This cytosis is where specific molecules bind to receptors, proteins that transport cholesterol in blood (LDL) and hormones target specific cells by this.

Receptor Mediated Cytosis

Receptor mediated cytosis is a form of _____

Pinocytosis