1.2-cell structure and organisation

Question 1

compare prokaryotic cells and eukaryotic cells

Answer 1

prokaryotic:
-small cells (1-10µm)
-ribosomes are small and free
-no membrane bound organelles
-DNA free
-plasmid present
-peptidoglycan cell wall
-uses mesosomes (a folded region of the cell membrane) for aerobic respiration

eukaryotic:
-large cells (10-100µm)
-ribosomes are larger and bound to the RER
-membrane bound organelles present
-DNA contained in a nucleus
-No plasmid present
-cellulose cell wall (if present)
-mitochondria used for aerobic respiration

Question 2

describe a virus

Answer 2

-do not fit the cell theory (no cell membrane/ cytoplasm/organelles/chromosomes)
-only reproduce with the help of a host cell
-composed of a protein coat/capsid surrounding DNA/RNA/a few genes
-extremely small (only able to be viewed with an electron microscope)
-outside of a host cell the virus exists as an inert viron

Question 3

describe cardiac muscles

Answer 3

-only found in the heart
-structure/properties are in between skeletal and smooth muscles
-have stripes but lack the long fibres of skeletal muscles
-contract rhythmically without any stimulation from nerves or hormones
-does not tire

Question 4

describe connective tissue

Answer 4

-connect/support/separate tissues and organs
-contain elastic and collagen fibres in extracellular fluid or matrix
-between the fibres are fat storing cells (adipocytes) and cells of the immune system

Question 5

describe epithilial tissue

Answer 5

-forms a continuous layer covering/lining the internal/external surfaces of the body
-have no blood vessels (but may have nerve endings)
-cells sit on a basement membrane made of collagen/protein
-often have protective/secretory functions

Question 6

describe skeletal muscle

Answer 6

-type of muscle tissue
-attached to bones and moves the skelton
-has bands of cells (fibres) which can contract powerfully
-tire easily and are voluntary muscles
-fibres form a striped pattern which can be viewed under a microscope
-often referred to as striped/striated muscle

Question 7

describe smooth muscle

Answer 7

-has individual spindl shaed cells that can contract rhythmically but less powerfully
-occur in the skin in the walls of blood vessels and in the digestive/respirator tracts
-involuntary muscles
-do not have stripes and are referred to as unstriped/unstriated muscles

Question 8

how do organelles work together during protein synthesis?

Answer 8

-ribosomes are produces in the nucleus and leave through the nuclear pores to attach to the RER
-the nuclear pores allow mRNA molecules (formed from DNA templates by transcription)to leave the nucleus. mRNA molecules attach to the ribosomes on the RER
-protein synthesis takes place at the ribsosomes. mRNA molecules contains the code for the primary structure of a protein (the order of amino acids in a polypeptide chains)
-the RE transports the polypeptides via transport vesicles which merge to the golgi body
-polypeptides are modified in the golgi body and converted to their tertiary structure (enzymes)
-enzymes are packaged into secretory vesicles and transported to the cell membrane
-secretory vesicles merge with the membrane and release the enzymes y exocytosis

Question 9

state the function of a nucleus

Answer 9

-it contains DNA which codes for and controls protein synthesis
-site of DNA replication
-Transcription produces mRNA templates

Question 10

state some of the strucutres found on bacteria

Answer 10

-ribosomes
-plasma membrane (inner wall)
-nucleoid
-cytoplasm
-capsule (outer wall)
-cell wall
-pili
-plasmid
-flagellum

Question 11

state the function of a nuclear envelope

Answer 11

separates the contents of the nucleus from the cytoplasm

Question 12

state the function of a nucleolus

Answer 12

-produces rRNA, tRNA and ribosomes

Question 13

state the function of centrioles

Answer 13

-form the spindle during cell division
-they are not present in higher plant cells

Question 14

state the function of chloroplast

Answer 14

-contains photosynthetic pigments which trap light energy for photosynthesis

Question 15

state the function of chromatin

Answer 15

condenses before cell division to form chromosomes

Question 16

state the function of lysosomes

Answer 16

-contains powerful digestive enzymes to break down worn out organelles/cells
-phagocytes use lysosomes to digest engulfed bacteria

Question 17

state the function of mitochondria

Answer 17

-ATP synthesis by aerobic respiration

Question 18

state the function of nuclear pores

Answer 18

-allow the transport of mRNA and ribosomes
out of the nucleus

Question 19

state the function of ribosomes

Answer 19

protein synthesis (primary structure forms)

Question 20

state the function of the cell wall

Answer 20

mechanical strength due to the high tensile strength of cellulose micro-fibrils
-transport of solutes via the apoplastic pathway
-cell to cell communication due to plasmodesmata

Question 21

state the function of the golgi body

Answer 21

-packaging proteins for secretion from the cell
-modification of proteins (by adding carbohydrates chains to form glycoprotein)
-produce lysosomes and digestive enzymes

Question 22

state the function of the plasmodesmata

Answer 22

connects cells via cytoplasm filled canals which pass through cell walls to allow transport via symplastic pathways

Question 23

state the function of the rough endoplasmic reticulum

Answer 23

-packaging and storing proteins
-producing transport vesicles which merge to form the glogi body

Question 24

state the function of the smooth endoplasmic reticulum

Answer 24

-produce, package, and transport steroids and lipids

Question 25

state the function of the vacuole

Answer 25

contains cell sap and stores solutes such as glucose

Question 26

what are eukaryotic cells?

Answer 26

-cells that have a nucleus and membrane bound organelles -these include plant and animal cells

Question 27

what are prokaryotic cells?

Answer 27

cells which have no membrane bound organelles (golgi body/ mitochondira/ chloroplast/nucleus/RER) -Bacteria

Question 28

what are some similarities and differences of mitochondria and chloroplast?

Answer 28

SIMILARITIES: -both have double membrane -both have highly folded inner membranes -both have a circular DNA for self replication -both have ribosomes -both produce ATP DIFFERENCES: -mitochondria have cristae but chloroplast have a thylakoid membrane -chloroplast contains photosynthetic pigments to absorb light energy, mitochondria do not -mitochondria have an inner matrix chloroplast have a stroma

Question 29

what are the 3 types of epithelial tissues?

Answer 29

1) cubodial epithelium-lines the kidney tubules and the small intestine 2)ciliates epithelium-composed of ells which transport substances like mucus in the bronchi and ova in the fallopian tubes (columnar) 3)squamous epithelium-consists of flattened cells on a basement membrane. form walls of the alveoli and lne the Bowman's capsule in the kidney

Question 30

what are the three types of tissue found in animals?

Answer 30

-epithelial tissue -muscle tissue -connective tissue

Question 31

what is the cell theory?

Answer 31

-all organisms are composed of cells (the basic unit of life) -organisms can be unicellular (amoeba/bacteria) or multicellular (plants/animals) -new cells arise from pre-existing cells

Question 32

what are the 4 types of connective tissues?

Answer 32

areolar tissues-found under skin and connects organs and tissues together collagen-forms tendons which connect muscle to bones ligaments-elastic tissues which connect bones adipose tissue-composed of fatty cells and is found under the skin and around organs. functions as an energy store/thermal insulator/protects delicate organs