Animal cells Flashcards
Describe the structure of the Nucleus
Largest cell organelle, enclosed by an envelope of two membranes that is perforated by nuclear pores. It contains chromatin which is the extended, useable form of chromosomes.
Also contains a darker area called the nucleolus.
Describe the function of the Nucleus
Chromatin/chromosomes are made of DNA which is the molecule of inheritance.
DNA is organised into genes which each code for a protein.
The nucleolus makes ribosomes.
Describe the structure of the Cell membrane
Phospholipid bilayer.
Made of phospholipids in two layers with proteins present. This structure described by the Fluid Mosaic Model.
Describe the function of the Cell membrane
A partially permeable barrier controlling exchange between the cell and its environment.
Also found around cell organelles e.g. nucleus, lysosomes etc.
Describe the structure of the Mitochondria
Two membranes forming an envelope, where the inner membrane is highly folded to form christae. Inner space is called the matrix.
Describe the function of the Mitochondria
Site of aerobic respiration in cells. Note – anaerobic respiration occurs in the cytoplasm.
Describe the structure of the Endoplasmic reticulum
A system of flattened membrane bound sacs called cisternae forming tubes and sheets. Joined to outer membrane and nucleus.
Describe the function of the Endoplasmic reticulum
If ribosomes are found on its surface it is called rough ER, and transports proteins made by the ribosomes. Smooth ER (no ribosomes) is the site of lipid synthesis.
Describe the structure of the Ribosome
Very small organelles consisting of a large and small subunit. Made of protein and RNA.
Describe the function of the Ribosome
Can be attached to endoplasmic reticulum (RER) or free in the cytoplasm.
Site of protein synthesis.
Describe the structure of the Golgi apparatus
A stack of flattened membrane bound sacs, called cisternae, continuously being formed at one end of the stack (cis) and budded off as vesicles at the other end (trans).
Describe the function of the Golgi apparatus
Internal processing and transport system e.g. of proteins formed by ER.
Make lysosomes.
Describe the structure of the Microvilli
Cellular membrane protrusions containing microfilaments that form a brush border on the cell’s outer surface. Increase the surface area of cells. Not present on all cell types.
Describe the function of the Microvilli
Involved in a wide variety of functions, including absorption, secretion, cellular adhesion.
Describe the structure of the Lysosome
A simple spherical sac bounded by a single membrane. Contain hydrolytic enzymes.
Describe the function of the Lysosome
Many functions all concerned with the breakdown of structures or molecules. E.g. getting rid of old organelles, digesting bacteria, cell suicide.
Describe the structure of the nucleolus
Dense spherical structure in the middle of the nucleus.
Describe the function of the nucleolus
The nucleolus makes RNA and ribosomes.
Describe the structure of the vesicles
Small spherical membrane bound sacs with fluid inside.
Describe the function of the vesicles
Transport vesicles are used to transport materials inside
the cell and secretory vesicles transport proteins that
are to be released from the cell, to the cell surface membrane.
Describe the structure of the centrioles
They are small tubes of protein fibres.
Describe the function of the centrioles
They form spindle fibres during cell division.
