Topic 2A: Cell Structure and Division

Question 1

Describe a lysosome

Answer 1

A round organelle surrounded by a membrane, type of golgi vesicle

Question 2

What’s the function of a lysosome?

Answer 2

Contains digestive enzymes (lysozymes), used to digest invading cells or to break down worn out components

Question 3

Describe a ribosome

Answer 3

A very small organelle that floats free in the cytoplasm or attached to rough ER, made of proteins/RNA

Question 4

What’s the function of ribosomes?

Answer 4

Where proteins are made-protein synthesis

Question 5

Describe rough ER

Answer 5

A system of membranes enclosing a fluid-filled space, covered in ribosomes

Question 6

What’s the function of rough ER?

Answer 6

Folds and processes proteins that have been made in the ribosomes

Question 7

Describe smooth ER

Answer 7

A system of membranes like RER, but without ribosomes

Question 8

What’s the function of smooth ER?

Answer 8

Synthesis’s and processes lipids

Question 9

Describe cell walls

Answer 9

A rigid structure surrounding cells in plants, algae and fungi mainly made of the carbs and cellulose

Question 10

What’s the function of cell walls?

Answer 10

Supports cells and prevents them from changing shape

Question 11

Describe the vacuole

Answer 11

Membrane-bound organelle found in the cytoplasm, contains cell sap (surrounding membrane is tonoplast)

Question 12

What’s the function of the vacuole?

Answer 12

Helps maintain pressure inside the cells and keep it rigid (stops plant wilting)

Question 13

How do Prokaryotic cells replicate?

Answer 13

Binary Fission

Question 14

Explain binary fission

Answer 14

Step 1) Circular DNA replicates main DNA once, plasmids divide multiple times
Step 2) Cells get bigger the DNA loops move to opposite poles.
Step 3) Cytoplasm divides
Step 4) 2 daughter cells are produced, each cell has one circular DNA but multiple plasmids

Question 15

Viruses aren’t cells, what are they?

Answer 15

Acellular, nucleic acids surrounding by a protein coat

Question 16

What do viruses need to re-produce?

Answer 16

Host-cell

Question 17

Once the virus is attached to the host-cell what does it do?

Answer 17

Inject their DNA/RNA into the host cell

Question 18

What’s the magnification equation?

Answer 18

Magnification= size of image/real object size

Question 19

How do you get from micrometers to nanometers?

Answer 19

X1000

Question 20

How do you get from nanometers to micrometers?

Answer 20

/1000

Question 21

What are microscope artifacts?

Answer 21

Things you see down a microscope that aren’t part of the cell, e.g fingerprints/bubbles

Question 22

What’s a TEM microscope?

Answer 22

TEM use electromagnets to focus a beam of electrons this is transmitted through the specimen. Denser parts of the specimen absorb more electrons appearing darker

Question 23

What’s a SEM microscope?

Answer 23

SEM’s scan a beam of electrons across a specimen. Knocking off electrons from the specimen (3D)

Question 24

Describe the chloroplast

Answer 24

Small flattened structure found in plant cells and algal cells, double membrane, inside also thylakoid membranes, forming grana

Question 25

What’s the function of chloroplast?

Answer 25

Where photosynthesis occurs

Question 26

Describe the Golgi apparatus

Answer 26

A group of fluid-filled membrane-bound flattened sacs, vesicles are often seen at the edges

Question 27

What’s the function of Golgi apparatus.

Answer 27

It processes and packages new lipids and proteins, also making lysosomes

Question 28

Describe golgi vesicles

Answer 28

A small fluid filled sac in the cytoplasm, surrounded by a membrane

Question 29

What’s the function of Golgi vesicles?

Answer 29

Stores lipids and proteins made by the Golgi apparatus and transports them out of the cell

Question 30

What is magnification?

Answer 30

How much bigger the image is than the original

Question 31

What is resolution?

Answer 31

Resolution is how detailed the image is, how well the microscope distinguishes between 2 points

Question 32

Name 2 types of microscope

Answer 32

Optical (light) microscopes and electron microscopes

Question 33

Name the 2 types of electron microscopes

Answer 33

Transmission and scanning (TEM&SEM)

Question 34

What do optical microscopes do?

Answer 34

Use light to form an image

Question 35

What’s the max resolution of optical microscopes?

Answer 35

0.2um including ribosomes ER and lysosomes

Question 36

What’s the max magnification of optical microscope?

Answer 36

1500x

Question 37

What do electron microscopes do?

Answer 37

Use electrons to form an image

Question 38

What’s the max resolution of a electron microscopes?

Answer 38

0.0002um

Question 39

What’s the max magnification of an electron microscope?

Answer 39

1500000x

Question 40

What are epithelial cells specialized to do?

Answer 40

Adapted to absorb food efficiently

Question 41

How are epithelial cells specialized?

Answer 41

Have villi for increased SA, micro villi for increased SA and loads of mitochondria for lots of energy

Question 42

How are red blood cells specialized?

Answer 42

No nucleus to make room for oxygen carrying haemoglobin

Question 43

How are sperm cells specialized?

Answer 43

Lots of mitochondria providing large amounts of energy

Question 44

What’s a tissue?

Answer 44

A group of cells grouped together to form tissues (Tissue-organ-organ system)

Question 45

What type of organisms is a prokaryotic cell?

Answer 45

Single celled

Question 46

What does the flagellum do?

Answer 46

Used for locomotion

Question 47

What are plasmids?

Answer 47

Small loops of DNA, small loops aren’t part of the main circular DNA, for antibiotic resistance

Question 48

What does the capsule do?

Answer 48

Capsule made up of secreted slime, protecting the bacteria from attacking other cells (immune system)

Question 49

What is the cell wall in fungal cells made out of vs plant cells?

Answer 49

Fungal= chitin Plant= cellulose

Question 50

Describe the cell-surface membrane

Answer 50

Membrane found on the surface of animal cells and just inside the cell wall of other cells, mainly made from lipids and proteins

Question 51

What’s the function of the cell-surface membrane?

Answer 51

Regulates the movement of substances into and out of the cell Also, has receptors on it that can respond to chemicals like hormones

Question 52

Describe the nucleus

Answer 52

An organelle surrounded by a nuclear membrane (double membrane) nucleus contains chromosomes and nucleolus

Question 53

What’s the function of the nucleus?

Answer 53

Controls the cell activities contains instructions to make proteins and ribosomes

Question 54

Describe mitochondria

Answer 54

Oval-shaped, double membrane (inner folded unto cristae) inside is the matrix, containing enzymes for respiration

Question 55

What’s the function of mitochondria?

Answer 55

Site of aerobic respiration, producing ATP

Question 56

Name an advantage and disadvantage of SEMS microscopes?

Answer 56

Ad: can be used on thick specimens and can be 3D Dis: Gives lower resolution than TEMS, only used on non-living specimens

Question 57

Name an advantage and disadvantage of TEMS microscopes?

Answer 57

Ad: Give high resolution, show small objects Dis: Can only be used on non-lining and thin specimens

Question 58

What’s cell fractionation?

Answer 58

Separating organelles from the rest of the cell

Question 59

What does homogenisation do and how do you do it?

Answer 59

Breaking up the cells, by vibrating or grinding the cells this breaks up the plasma membranes Solution must be kept ice-cold, isotonic and a buffer solution added to maintain pH

Question 60

Why do we filter the solution?

Answer 60

To get rid of larger cell debris

Question 61

What does ultracentrifugation do and why?

Answer 61

Separating the organelles, poured into tube and put into a centrifuge spun on a low speed. Heavy organelles are spun off first, when you increase speed each time lighter organelles come of each time

Question 62

What organelles are spun off, in which order?

Answer 62

Nuclei, mitochondria, lysosomes, ER and ribosomes