Cell Biology Flashcards by Evren Aririele

What is a cell?

The smallest unit of life

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What are the 3 main parts of the human cell?

Plasma membrane, cytoplasm, and nucleus

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What is extracellular fluid?

fluid outside of the cell

blood plasma, cerebrospinal fluid, cellular secretions

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What is the plasma membrane?

separates intracellular and extracellular objects in the cell

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What is the plasma membrane made of?

Phospholipid bilayer

oil-like consistency

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What does the plasma membrane consist of?

All organelles

proteins, cholesterol and carbohydrates

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Half of the plasma membrane mass is filled with what?

Proteins

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What can proteins do/act as inside the plasma membrane?

Form channels and pores for ions and molecules

Can also act as carriers

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What does cholesterol do in the Plasma Membrane?

Stiffens the membrane

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What do carbs do in the plasma membrane?

Give cells their identity and allow immune cells to recognize them as “self”

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How do cells form tissue?

Attach to one another by cell junctions

Form a community of cells and allow/prohibit certain molecules

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What are tight junctions?

Proteins on the plasma membrane of adjacent cells that fuse togehter

Impermeable

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What are desmosomes?

Linker proteins that bind neighboring cells together like a sheet

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Where are desmosomes abundant in?

tissues subject to stress like skin or heart muscle

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What is the role of hemidesmosome?

involved in the adhesion of epithelia to basement membrances

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What is the epithelia?

thin tissue outer layer of body’s surface inside and out

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What is the basement membrane?

thin, pliable sheet-like layer providing cell and tissue support

also a platform for complex signalling

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What are gap junctions?

communicating junctions allowing ions and small molecules to pass from one cell to the next

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What is difussion?

the movement of ions and molecules from high concentration to low

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What is osmosis?

The movement of WATER from high to low

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What is a hypotonic solution?

A solution that contains more dilute than cells

contains more water

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What is a hypertonic solution?

A solution that contains less dilute than cells

contains more solute

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What is an isotonic solution?

hae the same concentration of solutes inside and outside cells

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What moves large molecules in and out of cells?

Vesicles

the FedEX of cells

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What are the two types of vesicular transport?

Endocytosis and Exocytosis

What causes membrane potential? | or voltage

The diffusion of certain ions across the plasma membrane

What is the membrane potential of a cell at rest?

-50 to -90 millivolts (mV) | K+ is a key player in determining membrane potential

What balances the K+ ions in the cell?

Protein anions

What ions are outside of the cell?

Na+ ions | Balanced by Cl- ions

Does Cl- have an effect on membrane potential?

No | Only K+ and Na+ play a role

What is cytoplasm?

a semitransparent fluid | between the plasma membrane and the nucleus

What does cytoplasm contain?

Cytosol, Organelles and Inclusions

What is cytoplasm made up of?

water, proteins, salt, sugars and variety of other solutes

Does the mitochondria conduct aerobic or anaerobic cellular respiration?

Aerobic | requires oxygen

What is a ribosome?

dark staining granules

What do ribosomes do?

Synthesize protein | contain protein and RNA subunits

What are the two types of ribosomes?

Free and membrane bound

What is the Endoplasmic Reticulum?

extensive system of tubes and parallel sacs

What are the two types of ER?

Rough and Smooth

The Rough ER... | 4 characteristics

* studded with ribosomes * protein syntehsis occurs in vesicles * vesicles carried to golgi for modification * produce proteins that secrete and become part of the cell

The Smooth ER... | 4 characteristics

* metabolizes lipids * synthesizes cholesterol and phospholipids * cell detoxification * stores calcium ions

What is the golgi apparatus?

a stacked and flattened membranous sacs

What does the golgi apparatus do?

* it's a traffic director cell proteins * modifies and packages proteins and lipids made at the rough ER

What is a peroxisome?

spherical mebranous sacs containing a variety of enzymes

What do peroxisomes do?

Detoxify harmful substances (alcohol) and neutralize free radicals (unstable molecules)

What is a lysosome?

spherical membranous organelles containing digestive enzymes | trashcans of the cell

What do Lysosomes do?

when they rupture, the cell disgests itself (autolysis)

What is the endomembrane system?

a system of organelles working together to perform cell functions | ER, golgi apparatus, secretory vesicles, lysosomes and nuclear envelope

What is the cytoskeleton?

network of rods running through cytosol | cell skeleton

What role does the cytoskeleton play?

provides structural support for cells and cell movement | microfilaments, intermediate filaments, microtubules

# Cytoskeleton What do microfilaments do?

allow cell movement and act as a road

# Cytoskeleton What do intermediate filaments do?

provide mechanical structure

# Cytoskeleton What do microtubules do?

stimulate cell division and guide chromosomes correctly

What are centrioles?

small barrel-shaped organelles orientated at a right angle | contain microtubules

What are cilia?

whip-like cellular extensions

What does cilia do? | made of microtubules

Move substanes across the cell surface

What is a flagella?

whip like cellular extension (longer than cilia) | propels the cell itself

What are microvilli?

tiny finger-like extensions on top of cells | increase surface area

Where can you find microvilli?

on the surface of absorptive cells

What is the nucleus?

* control center of the cell * contains genes

What forms the nucleus?

* nuclear envelope * nucleolus * chromatin

Nuclear Envelope

barrier between nucleus and cytoplasm | contains pores

Nucleolus

dark staining spherical bodies on nucleus | where rNA is assembled

What is chromatin?

DNA combined with histone protein | coated in proteins and molecules

What are chromosomes?

condensed chromatin | 46 in somatic cells, 23 pairs

Sister chromatids

Chromosomes formed after cell division that are identical copies and are attached to ech other | attached by centromere

Homologous chromosomes

pair of chromosomes similar in size, shape and gene content | inherited from each parent, carry same genes in same order, diff. ver.