cell structure

Question 1

structure + function of the nucleus?

Answer 1

surrounded by nuclear envelope, and contains nucleolus and chromatin where ribosomes are made. chromatin is made up of DNA and histones and packages and condenses chromosomes. nucleus filled with nucleoplasm.

Question 2

structure + function of the nuclear envelope/membrane?

Answer 2

double membrane with space in-between surrounding the nucleus containing nuclear pores to allow small molecules to pass into the cytoplasm but keeps larger ones in its walls (chromosomes). connected to endoplasmic reticulum.

Question 3

structure and function of nucleolus

Answer 3

spherical structure in eukaryotic nucleus
produces ribosomes
made of proteins, DNA and RNA

Question 4

structure + function of Rough Endoplasmic Reticulum (RER)

Answer 4

series of flattened sacs enclosed in membrane and covered in ribosomes. facilitates protein synthesis w/ large surface area then transports newly synthesised proteins to Golgi apparatus.

Question 5

structure + function of Smooth Endoplasmic Reticulum (SER)

Answer 5

series of membrane bound sacs that synthesise (produces and processes) lipids and carbohydrates.

Question 6

structure + function of Golgi apparatus?

Answer 6

series of fluid-filled, curved and flattened membrane-bound sacs with vesicles surrounding edges. it modifies proteins and lipids and repackages them into vesicles. also produces lysosomes. adds carbohydrates to proteins to make glycoproteins.

Question 7

structure + function of lysosomes?

Answer 7

small vesicles containing digestive enzymes bound by a single membrane that engulfs and destroys old organelles. fuses with cell membrane, releasing its contents via exocytosis

Question 8

structure + function of mitochondria?

Answer 8

oval shaped and bound by a double membrane. the innermost is folded forming cristae and matrix inside containing enzymes needed for cellular respiration. site of aerobic respiration and ATP production.

Question 9

structure + function of centrioles?

Answer 9

hollow cylinders made up of 9 triplets of microtubules arranged at angles. used in cell division by producing spindle at opposite poles of the cell in order to pull chromatids apart. come in pairs to form centrosome

Question 10

structure + function of ribosomes?

Answer 10

made in the nucleus and composed of a large subunit and small subunit which attach in the cytoplasm. either prokaryotic-70S or eukaryotic-80S. if attached to RER=involved in protein synthesis, if free floating=involved in packaging proteins.
-made up of rRNA and proteins

Question 11

structure + function of flagella?

Answer 11

tail-like structure found on some eukaryotic cells made of bundles of microtubules which contract and propel cell forwards. aids mobility

Question 12

structure + function of cilia?

Answer 12

finger-like projections found on some cell surfaces containing bundles of microtubules that contract and move cilia. move substances in a wave-like motion. stationary/mobile

Question 13

describe the process of production and secretion of proteins.

Answer 13

-proteins are produced on ribosomes on the RER
-proteins are folded, processed and packaged in vesicles
-travel from RER to Golgi apparatus
-modified in Golgi apparatus and packaged in vesicles
-secretory vesicles transport proteins to cell membrane surface where it fuses and releases the protein via exocytosis

Question 14

structure + function of chloroplast?

Answer 14

where photosynthesis takes place. surrounded by double membrane (chloroplast envelope) and the fluid inside this is called stoma, containing enzymes involved in photosynthesis reactions. contains thylakoids (flattened sacs embedded w/ pigment) which stack to form grana which are joined together by lamellae

Question 15

structure + function of cell wall?

Answer 15

rigid outer layer providing cell structure and support. -made of peptidoglycan in prokaryotic cells
-made of cellulose in eukaryotic cells

Question 16

structure + function of plasma membrane?

Answer 16

-found in all cells
-selectively partially permeable membrane
-has phospholipid bilayer (amphipathic and contains a hydrophilic head region facing outwards and a hydrophobic tail region facing inward)
-intrinsic and extrinsic proteins involved in transport, support and cell signalling
-contains cholesterol to regulate membrane fluidity+increase stability.
-glycoproteins and glycolipids involved in cell adhesion, cell recognition and cell signalling
-cell surface membranes act as a barrier between the cell and environment and control substances exiting or entering cell
-membranes around organelles act as a barrier between organelle and cytoplasm, diving the cell into different compartments (compartmentalisation)

Question 17

structure + function of vacuole?

Answer 17

contains a fluid cell sap (solution of sugars, amino acids, mineral salts+waste chemicals dissolved in water). these move in and out cytoplasm as vacuole acts as a food store. it’s surrounded by tonoplast membrane. water moves into vacuole via osmosis. Improves cells rigidity

Question 18

structure + function of micro tubules

Answer 18

-fine, tubular, un branched structures (globular) made of protein tubular
-run through cell providing supporting scaffold
-determine cell shape
-made of the protein tubulin
-vesicles move along them
-make spindle fibres
-strong

Question 19

structure + function or microfilaments

Answer 19

-twisted double strands of the protein actin
-enables cell movement and keeps its shape, holds cell together because actin have contractile filaments
-important for cytokinesis (cell division)

Question 20

structure + function of intermediate filaments

Answer 20

-made of interwoven, rope strands
-structure varies depending on the type of tissue the cell is part of
-helps maintain shape, support nerve cell extensions, and attach cells together

Question 21

structure + function of the cytoplasm

Answer 21

jelly like substance in which chemical reactions occur.
contains enzymes
organelles bound to it

Question 22

resolution and magnification of a light microscope?

Answer 22

resolution - 0.2 micrometers
magnification - x1500

Question 23

resolution and magnification of an electron microscope?

Answer 23

resolution - 0.5-0.5nm
magnification - x1,500,000

Question 24

differences between eukaryotic and prokaryotic cells

Answer 24

-P are unicellular, E are multicellular
-P are smaller and simpler than E
-P cell wall made of murrain, E cell wall made of cellulose or chitin
-P circular dna, E linear dna
-P 0.1-5 micrometers, E 10-100 micrometers
-P 70s ribosomes, E 80s ribosomes

Question 25

difference between TEM and SEM

Answer 25

TEM: 2D image, higher resolution SEM: 3D image, lower resolution

Question 26

what is a laser scanning confocal microscope

Answer 26

-fluorescence microscopy -connected to a computer to produce a 3D image -looks at depths in a specimen -can observe live specimen -has pinhole that blocks out light

Question 27

structure and function of pili

Answer 27

-short, hair like structures -used to attract prokaryotic cells to other cells/surfaces

Question 28

structure and function of a capsule

Answer 28

-bacterial cells -slime layer made of polysaccharides -protects cell from attack by antibiotics/WBC’s

Question 29

difference between algal and fungal cells

Answer 29

algal-same organelles as plant, have chloroplast with different shape fungal-mostly same organelles as plant, no chloroplast, cell wall made of chitin

Question 30

how to calculate size of graticule divisions

Answer 30

size of one micrometer division / number of graticule divisions

Question 31

what is differential staining

Answer 31

using multiple stains to identify different cellular components and cell types

Question 32

what is the equation for magnification

Answer 32

magnification=image size/actual size