Cells: Structure of eukaryotic cells Flashcards
What is a eukaryotic cell
A cell that has a definite closed nucleus and organelles that are enclosed by a plasma membrane ( cell surface membrane)
What is a plasma membrane (cell-surface membrane)
Membrane found in eukaryotic cells that protects the interior of the cells from the outside
What is the function of a plasma membrane
It protects the cell from its surroundings by controlling the entry and exit of substances in and out of the cell
How is the plasma membrane adapted to carry out its function
It is made up of a phospholipid bilayer which acts as a barrier ( a semi permeable membrane) and the proteins in the plasma membrane assist with the transfer of molecules in and out of the cell
What is the function of the Nucleus
It controls the activity of a cell and is the site of DNA replication
Also produces mRNA which carries the genetic information needed to make proteins
What is a nucleus
It is a membrane bound organelle in a cell which contains DNA usually in the form of chromatin and is surrounded by its own membrane
What is the function of the Golgi body (Golgi apparatus)
It transports, modifies and packages proteins and lipids into vesicles for delivery to target destinations
What is the function of the Golgi vesicles
It directs lipids and proteins to targeted locations
What is the Endoplasmic reticulum
A series of membrane folds that connect to the nuclear envelope
What is the nuclear envelope
A double membrane that separates the nucleus from the cytoplasm
What is the function of a smooth endoplasmic reticulum
It synthesises and processes lipids within the cell
Rough endoplasmic reticulum function
Makes and synthesises the proteins that ribosomes produce and are folded and moved over to the golgi apparatus
How is the rough endoplasmic reticulum adapted to carry out its function
It is studded with ribosomes
How is the smooth endoplasmic reticulum adapted to carry out is function
It has branched networking which allows for an increased surface area
What is a ribosome
It is a tiny organelle that either floats freely in the cytoplasm or is attached to the endoplasmic reticulum
What is the function of a ribosome
A ribosome is the site of protein synthesis
What is ATP
ATP (adenosine triphosphate) is the energy-carrying molecule used in cells
What is the function of a mitochondrion
It is the site of aerobic respiration which provides the cell with all the energy it needs
Name and describe the features found in the mitochondria
- Outer membrane
- Inner membrane - Contains many folds which form cristae
- Matrix - space located in the enclosed inner membrane
- Intermembrane space - space located between the inner and outer membranes
How is the mitochondria adapted to its function
It has a double membrane with an inner one with many folds which form cristae - these folds allow for more surface area to be achieved
Function of a cell wall
Provides tensile strength and protection against stress which keeps plant cells rigid
What is the cytoplasm
A gel-like substance by which chemical reactions take place
What is the function of a vacuole
Contains the waste product of a plant cell and keeps the cell rigid
Name the features found in the chloroplast
- Stroma
- Thylakoids
- Grana (granum pl.)
- [Stroma] lamellae
- Chloroplast envelope (made of inner and outer membrane
- Ribosomes
- Starch grains
Outline thylakoids as a feature found in chloroplasts
- Flattened fluid-filled sacs
- Responsible for trapping light energy and transferring it into ATP
- Stack up to form grana
Outline the stroma as a feature found in chloroplasts
- The stroma is the fluid filling the inner space of the chloroplast
- The site of light-independent stage of photosynthesis
Outline granum as a feature found in chloroplasts
- A stack like structure (of thylakoids) containing chlorophyll
- Where light reactions of photosynthesis occur
Outline [stroma] lamellae as a feature found in chloroplasts
- Connect thylakoids of two different grana - increasing photosynthesis efficiency by making sure they do not clutter
Outline the chloroplast envelope as a feature found in chloroplasts
- Made of an inner and outer membrane
Outline ribosomes as a feature found in chloroplasts
Small 70S ribosomes responsible for producing chloroplast DNA
Outline the role of chloroplast DNA
It codes for some of the chloroplast proteins
Outline starch grains as a feature found in chloroplasts
Sugars formed during photosynthesis are stored inside starch grains
Chloroplasts function
It is the site of photosynthesis
Why is the rough endoplasmic reticulum rough
This is because it is studded with ribosomes
What are lysosomes
A special kind of golgi vesicle that are and membrane-bound organelle that contains digestive enzymes called lysozymes
What is the lysosome’s functions
They break down worn out or damaged organelles
They can contribute to the digestion of bacteria during phagocytosis
What is the function on the nuclear envelope
It separates the contents of the nucleus from the cytoplasm
What is the Nucleolus
An area inside the nucleus that is made up of RNA
What is the function of the nucleolus
It produces the cells ribosomes by combining rRNA with proteins to make them
What is mRNA
It stands for messenger RNA and it is a type of single-stranded RNA involved in protein synthesis
What is rRNA
It is the part of ribosomes that is responsible for making proteins
Were are ribosomes made
In the nucleolus
State the type of ribosome found in eukaryotic cells
80S ribosomes
State the ribosomes found in prokaryotic cell
70S ribosomes
What is a specialised cell
A cell that has undergone differentiation; having distinctive structure enabling a certain function
State the organisation that occurs to form organ systems
Specialised cells → Tissues → Organs → Organ systems
