cells and microscopes

Question 1

What happens during interphase?

Answer 1

• Cell is actively synthesizing proteins
• Chromosomes invisible
• Prior to mitosis, DNA replicates

Question 2

What happens during prophase?

Answer 2

• Chromosomes become visible
• Nuclear envelope disintegrates
• Nucleolus disappears

Question 3

What happens during metaphase?

Answer 3

• Spindle apparatus forms

- Chromosomes line up on the center of the cell

Question 4

What happens during anaphase?

Answer 4

• Spindle fibers attached to chromatids contracts

- Chromatids are pulled towards poles

Question 5

What happens during telophase?

Answer 5

• Chromosomes reach poles and become indistinct
• Nuclear envelope reforms
• Nucleolus reforms
• Spindle apparatus disintegrates

Question 6

What are the structural features of a nucleus?

Answer 6

nuclear envelope which has nuclear pores

contains chromosomes, consisting of protein-bound, linear DNA and one or more nucleoli

Question 7

What are the structural features of a mitochondrion?

Answer 7

smooth outer membrane, an inner membrane highly folded into cristae and the internal solution called matrix

Question 8

What is the function of a mitochondrion?

Answer 8

carry out aerobic respiration (making of ATP)

respiration reactions take place on the cristae and in the matrix

Question 9

What are the structural features of a cell surface membrane?

Answer 9

made up of a phospholipid bilayer with proteins, glycoproteins, glycolipids and cholesterol

Question 10

What is the function of the cell surface membrane?

Answer 10

partially permeable so controls the exchange between the cell and the environment (controls what enters and exits the cell)

Question 11

What is the name of the cell organelle that builds proteins?

Answer 11

rough endoplasmic reticulum

Question 12

What is the name of the cell organelle that release lysozyme?

Answer 12

Lysosomes

Question 13

What is the name of the cell organelle that makes lipids, steroids and some hormones?

Answer 13

Smooth endoplasmic reticulum

Question 14

Which organelles are involved with protein synthesis?

Answer 14

Rough endoplasmic reticulum, Ribosomes and Golgi apparatus

Question 15

What is the name of the cell organelle that carries out photosynthesis?

Answer 15

Chloroplast

Question 16

What are the two types of cells that form all life?

Answer 16

eukaryotic and prokaryotic

Question 17

What are the two main features of a virus that differentiate it from life on Earth?

Answer 17

Acellular and non-living

Question 18

What are the three components of a virus particle?

Answer 18

genetic material, capsid, attachment protein

Question 19

What type of cells are animal, fungal and plant cells?

Answer 19

eukaryotic

Question 20

What type of cells are bacteria?

Answer 20

prokaryotic

Question 21

Which three organelles do plant cells have that are not present in animal cells?

Answer 21

permanent vacuole, cell wall and chloroplasts

Question 22

What is the difference in chemical composition between a eukaryotic plant cell wall and a prokaryotic cell wall?

Answer 22

plants cell walls contain cellulose

bacterial cell walls contain murein

Question 23

What is the difference between the organelles in a prokaryotic cell and a eukaryotic cell?

Answer 23

prokaryotic cells lack membrane-bound organelles

Question 24

What is the difference between the ribosomes in a prokaryotic cell and in a eukaryotic cell?

Answer 24

prokaryotic cells have smaller 70S ribosomes

eukaryotic ribosomes are 80S

Question 25

State three differences between DNA in prokaryotic cells and DNA in eukaryotic cells

Answer 25

prokaryotic DNA: a circular loop, not associated with histone proteins, free in the cytoplasm eukaryotic DNA: linear chromosomes, associated with histone proteins, contained within the nuclear envelope

Question 26

What three other organelles may prokaryotic cells have?

Answer 26

one or more plasmids a slime capsule surrounding the cell one or more flagella

Question 27

Define magnification

Answer 27

the number of times greater the size of the image is than the size of the real object

Question 28

Define resolution

Answer 28

the ability to distinguish between two objects very close together higher resolution means more detail

Question 29

How can you calculate the magnification of an object?

Answer 29

magnification = image size / actual size of object

Question 30

What are the principles of light microscopy?

Answer 30

uses light as a source of radiation | light can be seen that passes through or reflects from the surface of the specimen

Question 31

What are the principles of transmission electron microscopes?

Answer 31

uses electrons as a source of radiation | electrons that pass through the specimen are detected

Question 32

What are the principles of scanning electron microscopes?

Answer 32

uses electrons as a source of radiation | electrons that are reflected from the surface on the specimen are detected

Question 33

What is the limitation of light microscopy?

Answer 33

magnification to 2000 x | resolution to 200 nm

Question 34

How is cell fractionation carried out?

Answer 34

homogenise the tissue in cold, isotonic buffer filter the resulting homogenate to remove large pieces of debris and whole cells ultracentrifugation at a very high speed

Question 35

Why do cells need to divide?

Answer 35

repair of damaged tissues, growth, asexual reproduction

Question 36

Why does the cell cycle need to be controlled?

Answer 36

so that growth is regulated and controlled, otherwise tumors may form

Question 37

What is the name given to cell division in prokaryotes?

Answer 37

binary fission

Question 38

What are the two types of nuclear division that take place in eukaryotic cells?

Answer 38

mitosis and miosis

Question 39

What are the products of mitosis?

Answer 39

two daughter cells that carry the same number of chromosomes as the parent cell and identical copies of their DNA

Question 40

List the four stages of mitosis in the correct order

Answer 40

prophase, metaphase, anaphase and telophase

Question 41

During which phases of mitosis does the nuclear envelope disintegrate and reappear

Answer 41

prophase and telophase

Question 42

Describe the appearance of a cell during metaphase

Answer 42

nuclear envelope is not present | chromosomes are aligned at the cell equator

Question 43

Describe what happens to the spindle fibres and the chromosomes during anaphase

Answer 43

the spindle fibres contract | the chromatids of each chromosomes are pulled to opposite poles of the cell

Question 44

Describe the appearance of a cell during telophase

Answer 44

the cell would contain two distinct nuclei

Question 45

what happens during cytokinesis?

Answer 45

the parent cell divides to form two daughter cells that are genetically identical to the parent cell

Question 46

List the three stages of interphase in order

Answer 46

G1, S and G2

Question 47

During which phase in interphase does DNA replication take place?

Answer 47

Synthesis

Question 48

During which stage in interphase does the formation of organelles and an increase in energy reserves take place?

Answer 48

G2

Question 49

Why does DNA replication have to take place?

Answer 49

so each daughter cell formed has an identical copy of DNA to the parent cell

Question 50

What are the key events during binary fission?

Answer 50

the circular DNA and plasmid DNA replicates the cytoplasm divides into two daughter cells each daughter cell has a copy of the circular DNA and varying numbers of copies of any plasmids

Question 51

During viral replication, does cell division take place?

Answer 51

No

Question 52

What is a mitotic index?

Answer 52

the ratio of dividing cells to the total number of cells in a population

Question 53

How is a mitotic index calculated?

Answer 53

number of dividing cells in a population / total number of cells in a population

Question 54

Would you expect cells in a root tip to have a high or a low mitotic index?

Answer 54

high mitotic index because the root tip is a region of rapid cell division