Cell Structure

360° Guided Tour of the Cell

Introduction to the Animal Cell

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Sol’s are considered to be the building
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blocks of an organism there are many
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different types of cells there are bone
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cells which make up the bones in your
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body blood cells which help carry oxygen
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to the different parts of your body
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muscle cells which help bring about
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movement and many more even though there
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are many types of cells every cell
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contains the same essential elements
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similar to how we humans have organs
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inside us a cell has organelles you can
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see these organelles around you these
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organelles are embedded in the cytoplasm
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which is a jelly-like fluid found
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between the cell membrane and the
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nucleus the cytoplasm is a gel-like
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substance enclosed by the cell membrane
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all the cell’s organelles float in the
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cytoplasm
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[Music]
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we use the term eukaryotic cell earlier
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what exactly does this mean a eukaryotic
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cell is one which has a cell nucleus and
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the other organelles enclosed in
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membranes these selectively permeable
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membranes protect each organelle they
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only allow certain substances to pass
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through and they prevent movement of
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certain substances through it the entire
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cell is surrounded by a cell membrane
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which is also a semi permeable membrane
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similar to the membrane surrounding the
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organelles in the cell this to
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selectively allows substances to enter
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and leave the cell
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let’s take a look at the main organelles
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that make up a cell to start with
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something needs to provide power to the
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cell this is the mitochondria and the
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mitochondria is also known as the
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powerhouse of the cell
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[Music]
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and now for the most important part of
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the cell the nucleus this organelle is
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also known as the brain of the cell it
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contains most of the cell’s genetic
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material the wall leg structure around
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it is the endoplasmic reticulum there
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are two different types of endoplasmic
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reticulum
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the rough endoplasmic reticulum is where
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there are ribosomes attached ribosomes
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are where the protein is synthesized in
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the cell ribosomes are also found freely
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in the cytoplasm
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[Music]
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the smooth endoplasmic reticulum doesn’t
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have any ribosomes attached it
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synthesizes lipids here we have the
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Golgi complex it acts like the cells
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very own post office it ships the
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proteins made by the endoplasmic
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reticulum to the other parts of the cell
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the rounded floating bodies we see here
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are lysosomes they are created by the
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Golgi apparatus they’re nicknamed the
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cleanup crew of the cell they help break
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down large molecules into smaller pieces
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that the cell can actually use
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[Music]
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we can think of a cell the same way we
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think about a machine all the parts of
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the cell have to work together to make
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sure that the cell functions properly
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the organelles work hard if they were
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lazy one day and chose not to work the
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cell would die we’ll learn more about
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what each organelle does in our next
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couple of adventures
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the nucleus is the most important
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organelle in the cell it stores the
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cell’s genetic material the genes and
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the nucleus are essentially your body’s
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blueprint it determines if your eyes are
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blue or brown whether you’re tall or
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short or even whether you’re a terrible
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singer or not it also ensures that all
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your cells and therefore your organs and
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your entire system functions properly
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the nucleus is found in most cells of
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most organisms on this planet and the
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genes would then describe how each
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organism is the nucleus is surrounded by
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the endoplasmic reticulum the
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endoplasmic reticulum is a continuous
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membrane system directly connected to
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the membrane surrounding the nucleus the
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endoplasmic reticulum forms a series of
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flattened sacs that we can see ahead of
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us it performs many functions and is
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very important in the synthesis
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modification folding and transport of
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proteins in the cell there are two types
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of endoplasmic reticulum in a eukaryotic
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animal cell the smooth endoplasmic
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reticulum
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[Music]
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and the rough endoplasmic reticulum the
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[Music]
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rough endoplasmic reticulum we see here
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has many tiny bodies attached to it
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these bodies are ribosomes the ribosomes
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are where proteins are synthesized there
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are also many ribosomes in the cytoplasm
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as we can see around us there are
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specific types of proteins that are
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synthesized at the endoplasmic reticulum
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for example some proteins stay in the
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endoplasmic reticulum while others might
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be transported elsewhere even though the
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rough endoplasmic reticulum is close to
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the nucleus the proteins that the
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nucleus needs are actually synthesized
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by the free ribosomes in the cytoplasm
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[Music]
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the smooth endoplasmic reticulum doesn’t
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have any ribosomes attached to it it is
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involved in the synthesis of lipids for
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the cell these lipids along with the
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proteins made by ribosomes are used to
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produce new cellular membrane for the
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cell
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[Music]
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the entire nucleus is covered by the
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nuclear envelope the nuclear envelope is
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a two-layered membrane it has an outer
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and an inner membrane
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[Music]
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each membrane has a layer of
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phospholipids the phospholipids look
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like a ball with a tail attached to it
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the phosphate heads are hydrophilic
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meaning they love water the fatty acid
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tails are hydrophobic they hate water
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the tails are pointing inwards since
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they hate water thus forming a
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phospholipid bilayer
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we can see small bodies on the nuclear
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membrane these are ribosomes again
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proteins are synthesized at the ribosome
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[Music]
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[Music]
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the small holes that we can see on the
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nuclear membrane are nuclear pores
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anything that needs to pass from the
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cytoplasm into the nucleus moves through
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these nuclear pores
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since the pores are so small only ions
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proteins or small molecules can move
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freely between the cytoplasm and the
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nucleus the nucleus also contains
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chromatin chromatin is made up of DNA
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and supporting structural proteins each
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chromatin is actually a very long string
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of DNA which coils itself to form a
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chromosome
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[Music]
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when the cell is getting ready to divide
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the DNA arranges itself to form
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chromosomes this DNA is packed very
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tightly if we unraveled all the DNA in
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just one human cell it would be over 6
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feet long the nucleus is very important
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because it controls and coordinates all
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cell functions is responsible for
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hereditary characteristics and also
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initiates cell division we’ll learn more
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about DNA and protein synthesis soon

 

How Mitochondria Produce Energy

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our body is made up of trillions of
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cells they all require energy to
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function this energy is created within
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ourselves in the mitochondria here food
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is converted into chemical energy called
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ATP ATP is released by the mitochondria
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so cells can use it
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mitochondria consists of two membranes
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an outer membrane separating it from the
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cytosol and an inner membrane
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surrounding the so called matrix the
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area between these membranes is called
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the inter membrane space ATP is
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generated at the inner membrane of
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mitochondria by an efficient mechanism
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called oxidative phosphorylation
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involving several membrane protein
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complexes nutrients provide high-energy
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electrons in the form of NADH which are
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used by the protein complexes to pump
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protons from the matrix to the
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intermembrane space this continuous
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pumping creates a proton gradient where
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the positively charged protons are
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attracted to the more negative matrix
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when the protons re-enter the matrix
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through the ATP synthase protein complex
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they catalyze the production of ATP