UNIT 1 Flashcards
- Discuss possible exceptions to cell theory
skeletal muscle fibers are larger/have many nuclei/are not typical cells
fungal hyphae are (sometimes) not divided up into individual cells
unicellular organisms can be considered acellular
because they are larger than a typical cell/carry out all functions of life
Explain how the surface are to volume ratio influences cell sizes.
small cells have larger ratio (than larger cells)/ratio decreases as size increases
surface area/membrane must be large enough to absorb nutrients/oxygen/substances needed
surface area/membrane must be large enough to excrete/pass out waste products
need for materials is determined by (cell) volume
Outline differentiation of cells in a multicellular organism
differentiation is development in different/specific ways
cells carry out specialized functions/become specialized
example of a differentiated cell in a multicelluar organism
cells have all genes/could develop in any way
some genes are switched on/expressed but not others
Describe the importance of stem cells in differentiation
stem cells are undifferentiated cells;
embryo cells are stem cells;
stem cells can differentiate in many/all ways / are pluripotent/totipotent;
differentiation involves expressing some genes but not others;
stem cells can be used to repair/replace tissues/heal wounds;
State one function of each of the following organelles: lysosome, Golgi apparatus, rough endoplasmic reticulum, nucleus, mitochondrion
lysosome: hydrolysis/digestion/break down of materials (macromolecules)
Golgi apparatus: synthesis/sorting/transporting/secretion of cell products
rough endoplasmic reticulum: site of synthesis of proteins (to be secreted)/ intracellular transport of polypeptides to Golgi apparatus
nucleus: controls cells activities/mitosis/replication of DNA/transcription of DNA (to RNA)/directs protein synthesis
mitochondrion: (aerobic) respiration/generates ATP
Distinguish between the structure of plant and animal cells
have cell walls, animals do not
have plastids/ chloroplasts, animals do not
have a large central vacuole, animals do not
store starch, animal cells store glycogen
have plasmodesmata, animal cells do not
animal cells
have centrioles, plant cells do not
have cholesterol in the cell membrane, plant cells do not
plant cells are generally have a fixed shape/ more regular whereas animal cells are more rounded
ompare the structures of prokaryotic and eukaryotic cells.
DNA: P: naked/loop of DNA; E: associated with protein/histones/nucleosomes/DNA in chromosomes
location of DNA: P: in cytoplasm/nuceloid/no nucleus; E: within a nucleus/nuclear membrane
membrane bound organelles: P: none; E: present
ribosomes: P: 70S ; E: 80S
plasma membrane: P & E: same structure within both groups
cell wall: P: peptidoglycan/not cellulose/not chitin; E: cellusose/chitin/not peptidoglycan
respiratory structures: P: no mitochondria; E: mitochondria