Cells Flashcards
The cell-surface (plasma) membrane
Mainly made of lipids and proteins
It regulates the movement of substances into and out of the cell
It has receptors on its surface which allows it to respond to chemicals e.g. hormones
The nucleus
Surrounded by a nuclear envelope (a double membrane) which has many nuclear pores
Contains chromosomes made from protein-bound linear DNA and one ore more nucleolus structures
It control’s the cells activities by controlling the transcription of DNA
The nucleolus is made up of ribosomes and proteins and makes ribosomes
Contains the hereditary genome
Mitochondrion
Double membrane
The inner membrane us folded into structures called cristae
Inside is the matrix which contains enzymes involved in respiration
The site of aerobic respiration where ATP is produced
Chloroplast
A flattened structure found in plant and algal cells
Double membrane
Thylakoid membranes inside which are stacked up to form grana
Grana are linked together by lamellae (thin, flat pieces of thylakoid membrane)
The Golgi Apparatus
A group of fluid-filled membrane-bound flattened sacs
Vesicles often line the edges of the sacs
It processes and packages new lipids and proteins
It makes lysosomes
A Golgi Vesicle
A small fluid-filled sac in the cytoplasm which is surrounded by a membrane and produced by the Golgi apparatus
They store lipids and proteins made by the Golgi Apparatus and transports them out of the cell via the cell-surface membrane
A lysosome
A round organelle surrounded by a membrane with no clear internal structure
It’s a type of Golgi vesicle that contains digestive enzymes called lysozymes
These are kept separate from the cytoplasm by the surrounding membrane and digest invading cells and break down worn components of a cell
Ribosomes
A very small organelle that either floats free in the cytoplasm or is attached to the RER
It’s made up of proteins and RNA
It’s not surrounded by a membrane
Folding and processing proteins
Synthesise proteins
The rough endoplasmic reticulum
A system of membranes enclosing a fluid filled space
The surface is covered with ribosomes
It folds and processes proteins that have been made by ribosomes
The smooth endoplasmic reticulum
A system of membranes enclosing a fluid filled space
No ribosomes on surface
Synthesizes and processes lipids
The cell wall
A rigid structure that supports cells and prevents them changing shape
In plants and algae it’s mainly made of the carbohydrate cellulose
In fungi it’s made of chitin
Cell vacuole
A membrane bound organelle found in the cytoplasm of plant cells
It contains cell sap which is a weak solution of sugars and salts
The surrounding membrane is called the tonoplast
Helps maintain pressure inside the cell and keep the cell rigid
Stops the plant wilting
Involved in the isolation of unwanted chemicals
Algal and fungal cells
Algal cells have the same organelles as plant cells
Fungal cell walls are made of chitin, not cellulose and they don’t have chloroplasts as they don’t photosynthesise
Cell specialization
In multicellular, eukaryotic organisms, specialized cells are grouped together to form tissues
A tissue is a group of cells that work together to form a particular function
Different tissues work together to form organs. Different organs make up organ systems
Prokaryotic DNA
No nucleus
DNA floats free in the cytoplasm
Circular DNA
Not associated with histones
Plasmids are small loops of DNA that aren’t part of the main DNA molecule
They contain genes for things like antibiotic resistance and can be passed between prokaryotes. They’re not always present
