_cell structure Flashcards
What does the cell membrane do?
surround all cells
What is the cell membrane made from?
2 layers of phospholipids
the cell membrane is semipermeable. What does this mean?
it selectively allows materials in and out
What do the embedded proteins in the cell membrane have?
various functions
What does the nucleus hold?
DNA contained with chromosomes
Why does DNA exist in the nucleus?
the dna in the nucleus is the template used to make proteins that are used in and out of the cell. Proteins control a huge variety of activities within the cell
What is the nucleus surrounded by?
a nuclear envelope that is porous and allows materials in and out
What kinds of materials need to get in and out of the nucleus?
signaling molecules (messengers) and enzymes need to enter the nucleus, mRNA need to leave the nucleus
What is contained in cytoplasm?
cytosol, a jelly like substance
What does cytoplasm do?
holds all the cell’s organelles in place
What is the cytoplasm a site for?
most of the chemical reactions in the cell
What are ribosomes?
Structures in the cell that build proteins from genetic info (DNA)
What 2 types of ribosomes are there?
free and bound
Where are free ribosomes found?
in the cytoplasm
What do free ribosomes do?
make proteins that will be used in the cell, like enzymes
Where are bound ribosomes found?
On the rough ER
What do bound ribosomes do?
make proteins that will be sent out of the cell
What type of protein do free ribosomes make?
Proteins used in the cell, many cell enzymes like those used in cellular respiration or for the lysosomes
What type of protein do bound ribosomes make?
Proteins that are sent out of the cell like hormones and other signaling molecules
What is the endoplasmic reticulum?
A folded organelle that surround the nucleus
What is the rough er covered in?
Ribosomes, which make proteins that are sent out of the cell
What does the rough er produce?
many enzymes
What does the smooth er make?
Lipids
What does the smooth er produce?
cell membrane and steroid hormones. Also detoxifies
In what cells are rough er mostly found?
pancreas and digestive tract cells
In what cells are smooth er mostly found?
endocrine system cells, liver cells
What is the Golgi apparatus?
It packs, labels, and transports proteins made at the rough er, and ships them out to the rest of the cell. Builds lysosomes
What does the Golgi Apparatus form?
a membrane around the protein to make a vesicle
What are lysosomes?
the digestive system of the cell, which contains enzymes (proteins)
What do lysosomes do?
break down food/toxins/waste
What does the mitochondria do?
Provide energy for the cell by doing cellular respiration
What does mitochondria change sugar (glucose) into?
ATP (a useable form of chemical energy)
What does the cytoskeleton do?
it supports the cell like an internal skeleton, and allows the cell to move and assist in cytoplasmic streaming
Where are centrioles (centrosomes) found in?
ONLY animal cells
What does centrioles (centrosomes) do?
Produce spindle fibers and assist in moving chromosomes during mitosis
What is the (central) vacuole?
a storage container for water, wastes and other substances
What does the large central vacuole do?
helps provide stabilising support in plant cells
What do chloroplasts produce?
sugar (glucose) from sunlight
What do chloroplasts contain?
chlorophyll, a pigment used in photosynthesis
What are chloroplasts contained in?
plant, fungal, algal, some protist cells
Where is the cell wall found?
In plant, fungal, bacterial cells
In plant cells, what is the cell wall composed of?
Cellulose, and provides structural support
What is the endosymbiotic theory?
mitochondria and chloroplasts were once free-living bacteria that got engulfed by a larger cell. they stayed inside the larger cell, and this is how modern-day eukaryotes were formed
What are some proof of the endosymbiotic theory?
Chloroplast and mitochondria have a double membrane, their own dna, and divide independently of the cell
What is used to view organelles that are too small to see in the light microscope?
Electron microscope
What is cell fractionation?
the process of breaking apart cells and separating the organelles
Why is it important to isolate organelles?
To study the specific function of the organelle when separated from the cell
How do you do cell fractionation?
- Break the cell open
- Spin the cell around really fast
- Big parts go to the bottom, small/less dense parts come to the top
- repeat 2&3 to get smaller and smaller organelles
