cell anatomy

Question 1

definition of a cell

Answer 1

the basic structural unit of all living organisms

Question 2

what are cells composed of?

Answer 2

water(80%), protein, lipid, carbohydrate, inorganic

Question 3

what is the plasmalemma

Answer 3

outer membrane of a cell
-biomolecula player of amphipathic phospholipids

Question 4

what is the role of the cytoskeleton?

Answer 4

-determines shape and fluidity of cell
→Allows movement of organelles and of the cell itself
→Gives shape and can change shape

Question 5

what is the cytoskeleton composed of>

Answer 5

thin/intermediate filaments and microtubules

Question 6

what is the role of the plasma membrane

Answer 6

separate cytoplasm from outside environment

Question 7

what is the permeability of the plasma membrane

Answer 7

selectively permeable (high to water/small hydrophobic molecules) (low to charged ions)

Question 8

what are the organelles of the cell

Answer 8

-nucleus
-mitochondria
-rER
-sER
-Golgi apparatus
-lysosomes
-inclusions

Question 9

what are inclusions?

Answer 9

-components synthesized by the cell itself
-not apart of metabolic activity
-example: adipose tissue

Question 10

function of the nucleus

Answer 10

contains genetic information

Question 11

function of the mitochondria

Answer 11

energy (ATP) production

Question 12

function of rER

Answer 12

protein synthesis

Question 13

function of sER

Answer 13

cholesterol and lipid synthesis/detoxification

Question 14

function of golgi apparatus

Answer 14

modification and packaging of secretions

Question 15

function of lysosomes

Answer 15

hydrolytic enzymes for intracellular digestion

Question 16

what type of proteins are cytoskeletal proteins?

Answer 16

filamentous cytosolic proteins

Question 17

what are the 3 classes of filaments

Answer 17

-microfilament
-intermediate filament
-micortubule

Question 18

what are microfilaments?

Answer 18

-composed of 2 actin strands
-involved in cellular movement, cell division and muscle contraction
-7nm

Question 19

what are intermediate filaments?

Answer 19

-6 proteins that bind intracellular elements together and to the plasmalemma
-Gives strength to structure of cell
-10nm
-These classes are used in pathology to identify tumour origins
-example: astrocytes

Question 20

what are microtubules?

Answer 20

-hollow and composed of alternating alpha and beta tubulin subunits that can be assembled or disassembled
-microtubules are important in cilia, flagella and the mitotic spindle
-microtubules act as the highway network of the cell as proteins Dynein and kinesin attach and move along them
-25nm

Question 21

what is kinesin?

Answer 21

-kinesin is an ATPase that moves toward the outside of the cell

Question 22

what is dynein?

Answer 22

-dynein is an ATPase that moves toward the cell centre

Question 23

why are kinesin and dynein important?

Answer 23

important in the movement of proteins

Question 24

what is cyostol?

Answer 24

Solution of proteins, electrolytes and carbohydrates which the cellular components are embedded

Question 25

what type of chromosomes does the nucleus contain?

Answer 25

-Euchromatin -Heterochromatin

Question 26

what is euchromatin?

Answer 26

DNA is more dispersed and undergoing transcription

Question 27

what is heterochromatin?

Answer 27

DNA highly condensed and not undergoing transcription

Question 28

which RNA synthesis happens in the nucleus

Answer 28

-mRNA -tRNA

Question 29

which RNA synthesis happens in the nucleolus

Answer 29

rRNA

Question 30

what are the 2 types of golgi network?

Answer 30

-cis -trans

Question 31

what does the cis golgi network do?

Answer 31

transports away from nucleus towards outside of cell

Question 32

what does the trans golgi network do?

Answer 32

transports towards nucleus

Question 33

what are intracellular junctions?

Answer 33

things that connect cells to other cells into a functional unit, mainly in epithelial cells

Question 34

what are the 3 types of intracellular junctions?

Answer 34

-occluding/tight (form diffusion barrier), -anchoring (provide mechanical strength) -communicating (allow for movement)

Question 35

what are occluding/tight junctions?

Answer 35

- Links cells to form a diffusion barrier and prevents diffusion - Water tight seal to prevent water flowing between cells (bladder/kidney)

Question 36

what are anchoring junctions?

Answer 36

Provides mechanical strength “cells adhere to one another” -prevents separation

Question 37

what are desmosomes (macula adherents)?

Answer 37

link sub membrane intermediate filaments of adjacent cells (macula adherents

Question 38

what are communicating (gap) junctions?

Answer 38

Allow movement of molecules between cells (selective diffusion- like a tunnel) -made up of connexins→ allows rapid communication

Question 39

what are connexins and what do they do?

Answer 39

(transmembrane proteins) -allows ions and cytokines to pass between cells→ allows rapid communication

Question 40

what is a junctional complex?

Answer 40

several types of junctions found in certain epithelial cells

Question 41

how can materials move across the cell?

Answer 41

-diffusion -transport proteins (pumps or channels) -vesicles (requires ATP)

Question 42

what are the 2 types of vesicular transport?

Answer 42

-endocytosis -exocytosis

Question 43

what is endocytosis?

Answer 43

-material from outside the cell is invaginated through the membrane and the endocytotic vesicle(endoscope) buds into the cell -(this process is receptor mediated)

Question 44

what is exocytosis?

Answer 44

opposite of endocytosis, materials leave the cell

Question 45

what is phagocytosis

Answer 45

bacteria binds to cell surface, cell engulfs it to form phagosome, binds with lysosome producing a phagolysosome