Module 2: section 1- Cell structure

Question 1

what are the organelles in an animal cell?

Answer 1

-plasma (cell surface) membrane
-rough endoplasmic reticulum
-nucleolus
-nucleus
-smooth endoplasmic reticulum
-lysosome
-ribosome
-nuclear envelope
-golgi apparatus
-cytoplasm
-mitochondrion

Question 2

what are the organelles in a plant cell?

Answer 2

plasma (cell surface) membrane
-CHLOROPLAST
-rough endoplasmic reticulum
-PLASMODESMA
-mitochondrion
-golgi apparatus
-VACUOLE
-smooth endoplasmic reticulum
-cytoplasm
-nuclear envelope
-nucleolus
-nucleus
-ribosome
-CELL WALL

Question 3

what is the plasma membrane and the composition&function

Answer 3

Term: Plasma (cell surface) membrane
Description: The membrane found on the surface of animal cells and inside the cell wall of plant cells and prokaryotic cells.
Composition: Made of lipids and proteins.
Function: Regulates the movement of substances in and out of the cell, and contains receptor molecules to respond to chemicals like hormones.

Question 4

what is a cell wall and its composition&function

Answer 4

Term: Cell wall
Description: A rigid structure that surrounds plant cells.
Composition: Made of the carbohydrate cellulose.
Function: Supports plant cells.

Question 5

what is the nucleus and its function?

Answer 5

Term: Nucleus
Description: A large organelle surrounded by a nuclear envelope with pores, containing chromatin (DNA and proteins) and a nucleolus.
Function: Controls the cell’s activities by regulating DNA transcription. The nucleolus makes ribosomes.

Question 6

what is the lysosome and its function?

Answer 6

Term: Lysosome
Description: A round organelle surrounded by a membrane, with no clear internal structure.
Function: Contains digestive enzymes to break down invading cells or worn-out cell components.

Question 7

what is the ribosome and its function&composition

Answer 7

Term: Ribosome
Description: A very small organelle that can either float free in the cytoplasm or be attached to the rough endoplasmic reticulum.
Composition: Made of proteins and RNA.
Function: The site where proteins are made.

Question 8

what is the rough endoplasmic reticulum and its function?

Answer 8

Term: Rough Endoplasmic Reticulum (RER)
Description: A system of membranes enclosing a fluid-filled space. The surface is covered with ribosomes.
Function: Folds and processes proteins made at the ribosomes.

Question 9

what is the smooth endoplasmic reticulum and its function?

Answer 9

Term: Smooth Endoplasmic Reticulum (SER)
Description: Similar to the rough endoplasmic reticulum, but with no ribosomes.
Function: Synthesizes and processes lipids.

Question 10

what is the vesicle and its function

Answer 10

Term: Vesicle
Description: A small fluid-filled sac in the cytoplasm, surrounded by a membrane.
Function: Transports substances in and out of the cell (via the plasma membrane) and between organelles.

Question 11

what is the golgi apparatus and its function?

Answer 11

Term: Golgi Apparatus
Description: A group of fluid-filled, membrane-bound, flattened sacs. Vesicles are often seen at the edges.
Function: Processes and packages new lipids and proteins; also makes lysosomes.

Question 12

what is the mitochondrion and its function?

Answer 12

Term: Mitochondrion
Description: Usually oval-shaped with a double membrane. The inner membrane is folded to form cristae, and inside is the matrix, which contains enzymes involved in respiration.
Function: The site of aerobic respiration, where ATP is produced. Found in active cells requiring lots of energy.

Question 13

what is the chloroplast and its function?

Answer 13

Term: Chloroplast
Description: A small, flattened structure in plant cells, surrounded by a double membrane. Contains thylakoid membranes stacked into grana, linked by lamellae, and surrounded by stroma.
Function: The site of photosynthesis. Some parts happen in the grana, and other parts in the stroma.

Question 14

what is the centriole and its function?

Answer 14

Term: Centriole
Description: Small, hollow cylinders made of microtubules (tiny protein cylinders). Found in animal cells and only some plant cells.
Function: Involved in the separation of chromosomes during cell division.

Question 15

what is cilia and its function?

Answer 15

Term: Cilia
Description: Small, hair-like structures on the surface membrane of some animal cells. In cross-section, they have an outer membrane and a ring of nine pairs of protein microtubules, with two microtubules in the middle. (Known as 9+2 formation)
Function: The microtubules allow the cilia to move. This movement is used to move substances along the cell surface.

Question 16

what is flagellum and its function?

Answer 16

Term: Flagellum
Description: Flagella on eukaryotic cells are like cilia but longer. They stick out from the cell surface and are surrounded by the plasma membrane. They contain two central microtubules and nine pairs around the edge.
Function: The microtubules contract to move the flagellum, propelling the cell forward (e.g., in sperm cells).

Question 17

how does protein production work in a cell?

Answer 17

-proteins are made in the ribosomes
-the ribosomes on the rough endoplasmic reticulum make the proteins that are excreted or attached to the cell membrane. the free ribosomes in the cytoplasm make proteins that stay in the cytoplasm. new proteins produce at the rough endoplasmic reticulum are folded and processed in the rough ER. then theyre transported from the ER to the golgi apparatus in vesicles. at the golgi apparatus, the proteins may undergo further processing. the proteins enter more vesicles to be transported around the cell.

Question 18

whatare the several functions of the cytoskeleton?

Answer 18

the cytoskeleton has 4 main functions:
-the microtubules and microfilaments support the cells organelles keeping them in position.
-they also help to strengthen then cell and maintain its shape.
- theyre responsible for the movement of materials within its cell. e.g the movement of chromosomes when they separate during cell division.
-the proteins in the cytoskeleton can also cause the cells to move. e.g the movement of cillia or flagella is caused by the cytoskeletal protein filaments that run through them. cytoskeleton propels the whole cell.

Question 19

what are the comparisons between eukaryotic cells and prokaryotic cells?

Question 20

organelles in prokaryotic cells (bacteria)

Answer 20

-flagellum
-DNA (bacterial chromosome)
-plasma (cell surface) membrane
-ribosome
-cell wall
-plasmid (ring of DNA)
1. plasmids are roughly 10th the size of eukaryotic cells
2. this means that normal microscopes arent really that powerful enough to look at their internal structure
3. can be seen under an electrin microscope

Question 21

what is magnification? and what is the formula?

Answer 21

how much bigger the image is than the specimen. its calculated using this formula: magnification= image size/object size

Question 22

what is resolution?

Answer 22

how detailed the image is. how well a microscope distinguishes between two points that are close together.if a microscope lens cant separate two objects then increasing the magnification wont help.

Question 23

what are the three types of microcopes?

Answer 23

1. light microscopes
2. laser scanning confocal microscope (a special type of light microscope)
3. electron microscopes
   -transmission electron microscope (TEM)
   -scanning electron microscope (SEM)