3A CELL STRUCTURE Flashcards
cytoplasm
a jelly-like liquid that makes up the bulk of the cell and contains the organelles
nucleus
an organelle containing the nucleic acids DNA and RNA, as well as protein, surrounded by a double nuclear membrane with pores
protoplasm
the cytoplasm and nucleus combined
ultrastructure
the detailed organisation of the cell, only visible using the electron microscope
intracellular
inside the cell
chromatin
the granular combination of DNA bonded to protein found in the nucleus when the cell is not actively dividing
nucleolus
an extra-dense region of almost pure DNA and protein found in the nucleus; it is involved in the production of ribosomes and control of growth and division
mitochondria
rod-like structures with inner and outer membranes that are the site of aerobic respiration
cristae
the infoldings of the inner membrane of the mitochondria which provide a large surface area for the reactions of aerobic respiration
eubacteria
true bacteria (prokaryotic organisms)
centrioles
bundles of tubules found near the nucleus and involved in cell division by the production of a spindle of microtubules that move the chromosomes to the ends of the cell
spindle
protein microtubules running the length of the cell, formed as the centrioles pull apart in mitosis and meiosis
70S ribosomes
the ribosomes found in the mitochondria and chloroplasts of eukaryotic cells and in prokaryotic organisms
endosymbiotic theory
a theory that suggests mitochondria and chloroplasts originated as independent prokaryotic organisms that began living symbiotically inside other cells as endosymbionts
lysosomes
organelles full of digestive enzymes used to break down worn-out cells or organelles or digest food in simple organisms
apoptosis (programmed cell death)
the breakdown of worn-out, damaged or diseased cells by the lysosomes
endoplasmic reticulum ER
- a 3D network of membrane-bound cavities
- links to the nuclear membrane
- plays an important role in the synthesis of many different chemical substances
rough endoplasmic reticulum RER
endoplasmic reticulum that is covered in 80S ribosomes and which is involved in the production and transport of proteins
exocytosis
the movement of large molecules out of cells by the fusing of a vesicle containing the molecules with the surface cell membrane; the process requires ATP
smooth endoplasmic reticulum SER
a smooth tubular structure similar to RER, but without the ribosomes, which is involved in the synthesis and transport of steroids and lipids in the cell
Golgi apparatus
- stacks of membranes
- modify proteins made elsewhere in the cell
- package them into vesicles for transport
peptidoglycan
a large, net-like molecule found in al bacterial cell walls made up of many parallel polysaccharide chains with short peptide cross-linkages
capsule
a layer found around the outside of some bacteria
pili
thread-like protein projections found on the surface of some bacteria
flagella
many-stranded helices of the contractile protein flagellin found on some bacteria; they move the bacteria by rapid rotations
plasmids
small, circular pieces of DNA that code for specific aspects of the bacterial phenotype
mesosomes
infoldings of the cell membrane of bacteria
gram-positive bacteria
bacteria that contain teichoic acid in their cell walls and stain purple/blue with Gramm staining
teichoic acid
a chemical substance found in the cell walls of Gramm-positive bacteria
cocci
spherical bacteria
bacilli
rod-shaped bacteria
spirilla
bacteria with twisted or spiral shape
vibrios
comma-shaped bacteria
obligate aerobes
organisms that need oxygen for respiration
facultative anaerobes
organisms that use oxygen if it is available, but can respire and survive without it
obligate anaerobes
organisms that can only respire in the absence of oxygen and are killed by oxygen
tissues
groups of specialised cells carrying out particular functions in the body
organs
structures made up of several different types of tissue to carry out particular functions in the body
epithelial tissues
tissues that form the lining of surfaces inside and outside the body
organ system
a group of organs working together to carry out particular large-scale functions in the body
Gram-negative bacteria
bacteria that have no teichoid acid in their cell walls; they stain red with Gram staining
Gram staining
a staining technique used to distinguish types of bacteria by their cell wall
bacteriophage
virus that attacks bacteria
80S ribosomes
• the main type of ribosome found in eukaryotic cells
• consisting of ribosomal RNA and protein
• made up of a 60S and a 40S subunit
• they are the site of protein synthesis
name 5 parts of the nucleus
- nuclear envelope
- nucleolus
- nuclear pores
- chromosomes/chromatin
- nucleoplasm
which organelle contains chromatin?
nucleus
which organelle is the site of translation?
ribosome
what is the main function of mitochondrion?
aerobic respiration
which organelle produces the spindle fibres during mitosis?
centriole
which organelle is responsible for the synthesis of lipids in the cell?
smooth ER
which organelle contains hydrolytic enzymes?
lysosomes
what is the main function of the nucleolus?
production of ribosomal RNA
which organelle packages proteins for export from the cell by exocytosis?
Golgi apparatus
which organelle is made of stacks of membranes and covered in ribosomes?
rough ER
which organelle is the site of respiration in a prokaryotic cell?
mesosome
prokaryotes contain which type of ribosomes?
70S (large 50S, small 30S subunits)
what substance forms the cell wall of prokaryotes?
peptidoglycan
which term means ‘before the nucleus’ ?
prokaryotic
which type of ribosomes do eukaryotes contain in their cytoplasm?
80S (large 60S, small 40S subunit)
how many membranes surround the nucleus?
two (a double membrane)
which organelle in animal cells, other than the nucleus, also contains DNA?
mitochondrion
which organelle is never found in prokaryotes or animal cells?
chloroplasts
what is the function of the plasma membrane?
control of transport into and out of the cell
which structures increase the surface area of the inner mitochondrial membrane?
cristae
which process describes how proteins are exported from cells?
exocytosis
what substance is the plant cell wall made of?
polysaccharide cellulose
which structures present in some animal cells increase the surface area of the cell membrane?
microvilli
which pigment makes chloroplasts green?
chlorophyll
which term means ‘true nucleus’?
eukaryotic
ehat structures are present in an animal cell but not in a plant cell?
lysosomes
centeioles
