A2.2 - eukaryotic cell structure (3a) Flashcards
what are cells?
cells are the basic structural unit of all living organisms
what are the processes of life in unicellular organisms?
Metabolism - chemical reactions within an organism
Reproduction - producing similar cells or organisms from existing ones
Sensitivity - responsiveness to stimuli
Homeostasis - regulating and maintaining a stable interior environment
Excretion - eliminating metabolic waste
Nutrition - organisms make use of nutrients/food
Growth - increase in size or number of cells
what are the functions of the cytoskeleton in eukaryotic cells?
the cytoskeleton’s functions are to maintain cell shape, anchor organelles and facilitate cell movement
- in animal cells, centrioles assemble microtubules to move chromosomes during cell division
- amoeba and phagocytes move though extension of the cytoplasm using microfilament
- animal cell movement is achieved through microtubules in cilia and flagella, which are assembled on basal bodies
how do plant, animal and fungal cells differ in terms of composition of cell walls?
plant - cellulose
animal - no cell wall
fungal - chitin
how do plant, animal and fungal cells differ in terms of size and function of vacuoles?
plant - large vacuole to store carbs and nutrition and maintaining turgor pressure and rigidity from water
animal - small numerous vacuoles with unique functions
fungal - small numerous vacuoles with unique functions
how do plant, animal and fungal cells differ in terms of presence of plastids?
plant - chloroplast to make carbs from photosynthesis and amyloplasts to store starch
animal - none
fungal - none
how do plant, animal and fungal cells differ in terms of structures involved in cell division?
plant - centrosomes
animal - centrosomes and centrioles
fungal - centrosomes
how do plant, animal and fungal cells differ in terms of presence of cilia and flagella?
plant - none
animal - cilia or flagella to direct nasal body
fungal - cilia or flagella but no nasal body
what are fungi?
a diverse group of eukaryotes, ranging from single-celled yeasts to multicellular mushrooms
what are the 3 structures common to cells in all living organisms?
what are the roles?
- DNA as genetic material - stores the genetic code as sequence of nucleotides and allows transfer of this information during protein synthesis and cell division
- a cytoplasm composed of a matrix of mainly water (called cytosol) - where most metabolic reactions of the cell occur
- a plasma membrane composed of a lipid bilayer with embedded proteins, which encloses the cytoplasm and functions in control of the movement of substances into and out of the cell, and supporting cell recognition and communication
what are the 2 types of eukaryotic cells?
- plant cells
- animal cells
what structures are present in eukaryotic cells for animal cells?
nuclues, lyosome, rough ER, smooth ER, golgi apparatus, nuclear pore, vesicles, centrosome, 80S ribosomes, plasme membrane, cytosol, mitochondrion, vacuole
what structures are present in eukaryotic cells for plant cells?
cell wall, chloroplast, vacuole, mitochondrion, plasma membrane, cytosol, vesicles, golgi apparatus, smooth ER, rough ER, nucleus, amyloplast, nuclear pore, 80S ribosomes
what are the components of all eukaryotic cells?
plasma membrane, compartmentalized cytoplasm, 80S ribosomes, nucleus, double membrane
what do membrane-bound cytoplasmic organelles include?
mitochondria, rough endoplasmic reticulum, smooth enoplasmic reticulum, Golgi apparatus, vesicles, vacoules, cytoskeleton
what is the function of the compartmentalized cytoplasm?
filling the space between membrane and nucleus
what is the function of the 80S ribosomes?
seen as dots free in the cytoplasm or attached to the rough endoplasmic reticulum, ribosomes are the site of protein synthesis via translation
what is the function of the nucleus?
to store genetic information:
- with numerous linear chromosomes made of DNA bound to histone proteins - visible as rods of condensed DNA
- contained in a double membrane with pores - allowing communication between the nucleus and the rest of the cell
what is the function of the mitochondria?
site of aerobic respiration, which releases energy and produces ATP
what is the function of the rough ER?
rough ER - synthesises proteins, using the attached 80S ribosomes, and packages them into vesicles for export, usually via the Golgi apparatus
what is the function of the smooth ER?
smooth ER - produces lipids (eg, membrane phospholipids), produces steroid hormones (eg, testosterone)
what is the function of the golgi apparatus?
forms lysosomes, and processes proteins from the rough endoplasmic reticulum before packaging them into vesicles for export
what are vesicles and vacuoles?
small membrane sacs
what is the function of a secretory vesicle?
secretory vesicles - move molecules such as proteins between organelles and then secrete them from the cell via exocytosis
what is the function of the lysosomes?
lysosomes in animal cells - which stain densely and contain hydrolytic enzymes to digest worn out organelles as well as materials brought into the cell by endocytosis
what is the function of the sap vacuole?
sap vacuole in plant cells - store carbohydrates for nutrition and water to maintain turgor pressure and cell rigidity
what are atypical cells?
cells with no or more than 1 nucleus
what are 2 examples of multi-nucleus cells?
aseptae fungal hyphae - has a continuous filament that contains multiple nuclei
skeletal muscle fibres - multiple nuclei on elongated cells to allow for larger contraction
what are 2 examples of anucleate cells?
erythrocytes (red blood cells) - no nucleus to carry more oxygen and biconcave shape increases sa:v ratio to maximise exchange
phloem sieve tubes - cells connected end-on-end with pores that rely on companion cells to supply nutrients and ATP
