STRUKTUR DAN FUNGSI SEL - BIOLOGI KELAS 11 SMA

[Music]

Hello little brothers and sisters, meet again with Kak

Febri in this video we will

discuss biology material, namely the structure

and function of cells. Before we start

learning, don't forget for those who haven't

subscribed to subscribe to the channel first,

click the bell and share it with

your friends as much as possible

so that we can learn together on

this channel.

What are cells? They are the smallest units

that make up the bodies of living things and

are where

various types of life functions are carried out. The structure of

cells was first observed by Robert

Hooke in 1665 by observing a

cork slice under a microscope.

Based on their structure, cells are divided

into prokaryotic and eukaryotic cells

where the fundamental difference is that

in prokaryotic cells there is no

membrane that encloses the cell nucleus. Prokaryotic cells

are found in eubacteria and

archaebacteria. Well, here is a

complete table of differences between prokaryotic

and eukaryotic cells. In prokaryotic cells,

because they do not have a membrane that encloses the

nucleus, DNA is located in the cytoplasm

mixed with other organelles,

while in eukaryotes, most of the

DNA is found in the nucleus which is

wrapped in a nuclear membrane. The size of

prokaryotic cells is smaller compared to

Eukaryotic cells prokaryotic cells have a

much smaller number of organelles

than eukaryotic cells

where eukaryotic cells have

complete organelles such as the nucleus

mitochondria chloroplasts

endoplasmic reticulum and others prokaryotic cells

are found in

unicellular organisms while eukaryotic cells can be

found in unicellular

and multicellular organisms then the

most important difference is

the presence of a nuclear membrane prokaryotic

do not have a nuclear membrane while

eukaryotes have a nuclear membrane and

organelles that have membranes

animal cells and plant cells also have

several differences in the size of plant cells are

usually larger than animal cells

plant cells have cell walls

so they have a fixed shape

while animal cells do not have

cell walls so their shape is not

fixed in plant cells there are

plastid organelles in animal cells there are no

plastids in animal cells there are

lysosome organelles and centrioles while plants

do not have lysosome and centrioles in

plant cells the function carried out by the

golgi body is replaced by the

dictiosome organelle then plant cells

have vacuoles while animal cells

do not have vacuoles are only found in

some unicellular organisms and Of

course in plant cells there is

green leaf substance or chlorophyll while in

animal cells there is no chlorophyll next

we will discuss the parts of the cell and their

respective functions starting from the

cell wall the cell wall is a layer

outside the cell membrane that surrounds

certain types of cells such as

plant cells and its function is to limit the space

for cells to expand another function

of the cell wall is to

maintain the shape of the cell to be a

supporter to provide protection both

mechanically and physically to prevent

fluid loss and control the size of the cell when the

cell absorbs water the cell wall in

plants is composed of pectin

cellulose fiber and hemicellulose

next there is a cell membrane the cell membrane

is a membrane that wraps the cell that

functions to protect the inside of the

cell as a place for substances to enter and exit

from the outside and into the cell as well as a

receptor or marker of the identity of a

cell well pay attention to the following cell membrane structure

yes the cell membrane is composed of

biliary lipids or fats Two layers

commonly called phospholipids because the

head is composed of

hydrophilic phosphate and the tail is

composed of hydrophobic lipids or fats

then there are

integral proteins and peripheral proteins

Where both have important functions in the

process of transporting substances in and out of cells

and there are glycolipids that function

as markers or identities of a cell

and also glycoproteins that function

as receptors or receive stimuli

from outside the cell Well, that was the

structure and function of the cell membrane,

next we will discuss one by one the

cell organelles and their respective functions, the

organelles are suspended in the

cell fluid that we call cytoplasm

where the cytoplasm is composed of water,

protein, carbohydrates, fats, minerals and

vitamins, the first organelle is the

nucleus where the nucleus is wrapped by

two layers of membranes, its function is to

regulate all cell activities and in it

contains genetic material

in the form of DNA, the next organelle is the

endoplasmic reticulum or reticulum located

close to the nucleus if it is studded with

ribosomes, it is called rough ER, its function is to

transport or transport proteins,

there is also a smooth ER that functions to

synthesize fat, next from the bosok

that functions to produce or

synthesize proteins and there are mitochondria,

mitochondria are usually called the House of power,

their function is where cell respiration and

where energy is produced, mitochondria

have a double membrane, inside the

outer membrane there is a grooved membrane

called cristae, and inside there is an

empty space filled with fluid called

the matrix,

then there is the golgi body or commonly

called the golgi complex or

golgi apparatus, its function is where protein processing or

modification is carried out and is responsible

for the secretion process Then there are lysosomes lysosomes are

only found in

animal cells the function of lysosomes is for

intracellular digestion recycling

damaged cells and destroying pathogens

pathogens that cause disease

centrioles are organelles that are only found

in animal cells centrioles play an important role

in the process of cell division Then there are

microtubules whose function is to

maintain the shape of the cell plays a role in

cell movement because it is a component of

flagella and cilia in

unicellular animals and also plays a role

in the process of cell division because

microtubules are components of

spindle threads then there are

plastids and vacuoles which are only found in

plant cells plastids are divided into

chromoplasts chloroplasts and leucoplasts

chromoplasts are plasts that

synthesize and store pigments other than

chlorophyll while chloroplasts contain

chlorophyll and are where

photosynthesis occurs leucoplasts are plastids

that do not function to store

pigments divided into lipidoplus which

functions to store fat and

amyloplasts which functions to store

starch while vacuoles are

large sacs that function to store

fluids and compounds such as enzymes

alkaloids lipids mineral salts amino acids

and acids organic Well that was the explanation

about the functions of organelles

next we will discuss about

cell transportation cell transportation

is divided into two, namely

passive transport and active transport passive transport

is the movement of molecules of substances in the direction of the

concentration gradient so that it does

not require energy on the other hand

active transport is the movement of

molecules of substances against the concentration gradient

so that it requires energy

passive transport consists of

osmosis diffusion and facilitated diffusion

while active transport examples

are endocytosis and exocytosis

diffusion is the movement of

dissolved molecules from high concentration or

hypertonic to low concentration or

hypotonic while Osmosis is

the movement of water from low concentration

to high concentration

facilitated diffusion is a diffusion process that

occurs with the help of membrane proteins

illustration you can see in the

picture below yes the process of diffusion and

osmosis will continue to occur

until equilibrium is reached

fluid concentration inside and outside the

cell

next we will discuss about

active transport some

active transport events include

endocytosis which is the event of entry of

substances into cells through the formation of

cell membrane sacs for example

phagocytosis and pinocytosis there is also

exocytosis which is the event of exit of

substances from inside the cell

using vertical sacs

formed by the golgi body and there is also a

pump Sodium and potassium ions

this mechanism is carried out to maintain the

concentration of potassium in the cell

normally the concentration of potassium in the

cell is high and the concentration of sodium

in the cell is low conversely outside the cell

sodium is high and potassium is low the

difference in concentration must be

maintained so that important physiological processes

in the cell are not disturbed The

following is the response of cells to

differences in the concentration of our solution starting

from animal cells that do not have

cell walls If animal cells are put

into isotonic means the concentration of the

solution inside and outside the cell is

balanced so that there is no more

movement of dissolved molecules or

water and there is no change in the shape

or size of the cell if the cell is put

into a hypertonic solution then the water

inside the cell will come out a lot because the

solution outside is more concentrated so that the cell

that loses a lot of water will

shrink the event is called crenation

conversely if animal cells are put

into a hypotonic solution then water from

outside will enter the cell

so that the cell will swell and

over time will burst the event

is called hemolysis while in

plant cells if the cell is put into a

hypertonic solution then water will

move a lot from inside to outside the cell so that the

cell will lose a lot of water and

shrink then the cell membrane will be released

from the cell wall the event is called

plasmolysis conversely if plant cells

are put into a solution Hypotonic,

then a lot of water will move from outside

to inside the cell so that the cell will

swell because it absorbs too much

water or is usually called turgit.

We have finished discussing the material

regarding the structure and function of cells. Hopefully it is

easy to understand and useful. Keep up

the good work of learning and keep

learning with Sigma Smart because you

can learn from anywhere.