3A Cells

Question 1

Nucleus structure and function

Answer 1

nuclear envelope with nuclear pores
chromatin (DNA and proteins)
nucleolus (produces ribosomes)

controls cell activity by controlling DNA transcription to make proteins

Question 2

lysosome structure and function

Answer 2

round organelle with membrane
contains digestive enzymes (lysozyme)

Question 3

Ribosome structure and function

Answer 3

No membrane, a large and a small subunit formed of proteins and RNA
It is the site where proteins are made

Question 4

Rough endoplasmic reticulum structure and function

Answer 4

membranes enclosing fluid, with ribosomes covering the surface
it folds and processes proteins made at the ribosomes

Question 5

Smooth endoplasmic reticulum structure and function

Answer 5

Membrane system enclosing fluid
Synthesises and processes lipids

Question 6

Golgi apparatus structure and function

Answer 6

Group of flattened membrane bound fluid sacs
it processes and packages lipids and proteins
makes lysosomes

Question 7

Mitochondrion structure and function

Answer 7

Oval shaped with a double, folded inner membrane (folds are called cristae) the matrix contains enzymes used in respiration
Site of aerobic respiration

Question 8

Centriole structure and function

Answer 8

Hollow cylinders made of microtubules
involved with the separation of chromosomes during cell division

Question 9

Protein synthesis

Answer 9

Proteins produced at the ribosome with a primary structure
Processed and folded in the RER
Transported in vesicles to the Golgi apparatus
Further processing eg adding sugars
Transported in vesicles to the cell membrane where the vesicles fuse and they are released through exocytosis

Question 10

Draw a eukaryotic cell cell

Answer 10

nucleolus
nuclear envelope
RER and SER
golgi
Mitochondria
ribosomes
centrioles
lysosome
cell membrane

Question 11

Draw a prokaryotic cell

Answer 11

Free floating circular DNA
plasmids
flagellum
ribosomes
cell membrane
cell wall
pili
capsule
mesosomes

Question 12

Differences between eukaryotic and prokaryotic cells

Answer 12

80S ribosomes in eukaryotes 70S in prokaryotes
Plasmids, flagella, cell wall of murein, capsule, mesosomes, pili are not found in eukaryotic cells

Question 13

Structure and function of prokaryotic cells

Answer 13

flagellum- hair like structure improves motility
plasmids- small loops of DNA which can be passed between prokaryotes, can contain antibiotic resistant genes
circular DNA- no nucleus, free floating
cell wall- made of glycoprotein murein, supports the cell and keeps its shape
pili- small hair like structures which help cells stick together
capsule- secreted slime which protects from attack from the immune system
Mesosomes- inward folds of the plasma membrane with no apparent function

Question 14

magnification equation

Answer 14

magnification= image/real

Question 15

light vs electron microscopes

Answer 15

light- lower resolution so less detailed, can be used on living organisms
electron- higher resolution, larger magnifcation

Question 16

cell organisation

Answer 16

Similar cells-> tissues -> organs -> organ system

tissues: a group of cells specifically adapted to work together to carryout a function

organs: a group of different tissues that work together

organ system: different organs working together to provide a function

Question 17

Stages of mitosis

Answer 17

(I)PMAT
Interphase: DNA is unraveled and duplicated and cell organelles are duplicated
Prophase: The nuclear envelope breaks down, chromosomes condense and centrioles move to the poles
Metaphase: the chromosomes line up along the middle of the cell and spindle fibres attach to the centromere
Anaphase: spindle fibres shorten pulling the sister chromatids apart to opposite poles of the cell
Telophase: the chromosomes become long and thin again, nuclear envelopes form around each group. cytokinesis occurs and the cytoplasm splits into tw forming two identical daughter cells.

Question 18

How to prepare lab stained root tips

Answer 18

Cut off the tip of a growing root.
Add the root into 60°C hydrochloric acid for 5 minutes
Rinse with cold water and dry
Place on slide
Cut off 2mm of the tip and macerate with mounted needle
Add toluidine blue stain + cover slip

Question 19

mitotic index: definition and equation

Answer 19

The proportion of cells undergoing mitosis

mitotic index= number of cells with visible chromosomes/total number of cells