LECTURE EXAM 2

Plasma membrane

controls entry in/out of cell

Cytoplasm

semi-fluid matrix (liquid is cytosol)

Ribosomes

Assembling polypeptide chains

Organelles

membrane bound compartments

• nucleus - contains DNA

• mitochondria - energy production (ATP)

Endoplasmic reticulum

• Rough: modifies new polypeptide chains

• Smooth: synthesizes lipids

Golgi body

modifies, sorts, ships new proteins and lipids

Vesicles

storage, transport, digestion

Lysosomes

waste digestion

Cellular Respiration

• requires oxygen (aerobic)

• produces large amount of ATP

Fermentation

• does not require oxygen (anaerobic)

• produces much less ATP

Catabolic Pathways

• break down complex molecules into simpler compounds

• release energy

Anabolic Pathways

• build complex molecules from simpler ones

• consumes energy

Glycolysis

• first phase of cellular respiration

• location: cytoplasm

• starts with 6 carbon glucose → splits into 2 pyruvate (3 carbon each)

NAD+

• coenzymes in all living things that accepts electrons

• acts as an electron carrier: accepts high-energy electrons and hydrogen atoms from glucose breakdown

• becomes NADH after gaining electrons

NADH

• store the high-energy electrons it gained from glucose

• carries energy to the Electron Transport Chain (ETC) in the mitochondria

• at the ETC, NADH donates electrons, driving ATP production

Why is the cell small?

• small cells are more efficient and service better

• small size = advantage

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• volume grows faster than surface area

• not enough surface to bring in nutrients & remove wastes

Nucleus

Command center — contains DNA

Cytoskeleton

• complex network of protein fibers in cytoplasm

• provides shape, movement, and organization

Microtubules (thickest)

• straight, hollow rods of tublin

• maintain cell shape

• serve as tracks for organelles/vesicle movement

• separate chromosomes in cell division

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• movement of cilia (repository) and flagella (sperm)

Microfilaments (thinnest)

• solid rods of actin

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Functions:

• muscle contraction

• pinches the cell into two during cell division

• provides shape and mobility

Intermediate Filaments (in between)

• structure: diverse group of rope-like fibers

• more permanent than microtubules and microfilaments

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functions:

• maintain cell shape

• provide mechanical strength

• anchor organelles (e.g hold nucleus in place)

Mitochondria

• produces ATP through cellular respiration

• bound by a double membrane

Ribosomes

Function: site of protein synthesis

• link amino acids together with peptide bonds → form polypeptide chains

Rough ER

• modifies proteins made by the ribosomes

• the ribosomes build amino acid chains (polypeptide chains)

• the polypeptide chains are then folded into their shape

Smooth ER

• detoxifies certain drugs (via enzymes)

• phospholipids and steroids are made here

• does not have ribosomes

Golgi Body (aka golgi apparatus)

• the UPS of the cell!!

  • products (proteins and lipids) from the smooth and rough ER are modified and repackaged

  • creates lysosomes

Lysosomes

• the garbage disposal of the cell

• digests, recycles, and expels

  • e.g. worn out organelles, returns monomers into the cytoplasm plasm, expels indigestiable residues

Vesicle

a membrane bound sac formed during endocytosis

Lysosomal storage disease

the absence of one enzyme → accumulation of undigested molecules

Cilia

• numerous, short, back-and-forth motion (e.g respiratory tract)

• movement caused by microtubules

Flagella

• single, long, whip-like motion (e.g sperm)

  • movement via microtubules

• core structure: 9 + 2 arrangement of microtubules

Centriole

• 9 sets of microtubules

• help divide chromosomes ig??

Nucleolus

• dense, dark-strained structure inside the nucleus

• produces ribosomal RNA (rRNA)

Nuclear Envelope

• double membrane (two lipid belayers)

• contains nuclear pores that regulate exchange of materials

• protects the DNA form the cytoplasm

• continues with the endoplasmic reticulum

Nucleoplasm

• aka nuclear sap

• gel-like material filling the nucleus

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Functions:

• suspends nuclear structures

• allows diffusion of ions, molecules, and nucleotides within the nucleus

• acts a s a cushion, protecting DNA and organelles from damage

Apoptosis

• aka cell death

• if damage is severe, the cell may self-destruct

Chromatin

• DNA + associated proteins

• condense into chromosomes during cell division

Chromosomes

• are made of DNA wrapped around proteins (chromatin)

  • “aka” DNA and specialized proteins

Cristae

• the site of the final phase of respiration

  • the inner membrane of the mitochondria (the folded part)