Cell Biology

Question 1

what are the small structures found in cells known as?

Answer 1

organelles

Question 2

what structure do all cells have?

Answer 2

cell membrane

Question 3

what is a cytoplasm?

Answer 3

A jelly like substance in which chemical reactions take place

Question 4

what are the organelles in which plant cells have but animal cells don’t?

Answer 4

cell wall
chloroplast
vacuole

Question 5

what is the function of the nucleus?

Answer 5

contains cell chromosomes made of DNA.

Holds genetic information which controls cell activities

Question 6

what is the function of the cell membrane?

Answer 6

consists of phospholipid and protein molecules.

Selectively permeable, controls the entry and exit of materials in and out of the cell

Question 7

what is the function of the mitochondria?

Answer 7

Site of aerobic respiration.

found in great abundance in cells with high energy demands, such as muscle cells

Question 8

what is the function of the ribosome?

Answer 8

Site of protein synthesis.

found in the cytoplasm or attached to tubular structures in the cell

Question 9

what is the function of a chloroplast?

Answer 9

Site of photosynthesis.

contain green pigment chlorophyll which absorbs light energy

Question 10

what is the function of the vacuole?

Answer 10

Contains cell sap, which is a solution of salts and sugars.

it is important in maintaining the cell shape

Question 11

what is the cell wall made from?

Answer 11

A carbohydrate called cellulose.

Question 12

how do bacterial cells differ from other cells?

Answer 12

the cell wall is not made from cellulose
they do not have a nucleus to contain genetic material, instead they have one large loop of chromosomal material and several smaller rings known as plasmids.

Question 13

which two cells have a cell wall in which is not made from the carbohydrate cellulose?

Answer 13

bacterial

fungal

Question 14

what does the cell membrane consist of?

Answer 14

Proteins

Phospholipids

Question 15

what is the membrane structure referred to as?

Answer 15

fluid mosaic model

Question 16

what are the 3 functions of proteins in a cell membrane?

Answer 16

form channels, creating pores. this allows passage of molecules small enough to travel through the pores by passive means.
embedded in the phospholipid layer or may lie on its surface. some of these may act as receptors for hormones or antibodies. Others act as enzymes for chemical reactions.
act as carrier proteins for the process of active transport of materials across the membrane.

Question 17

what does passive transport rely on?

Answer 17

substances are found in different concentrations in different places. substances always move from a high to a low concentration in passive transport.

Question 18

what is the definition of diffusion?

Answer 18

the movement of molecules or ions from a region of high concentration to a region of low concentration.

Question 19

give examples of where diffusion is used

Answer 19

oxygen and glucose enter cells by diffusion for the process of aerobic respiration.
The removal of waste products such as carbon dioxide or urea.

Question 20

What is the definition of osmosis?

Answer 20

the movement of water molecules from a region of high water concentration to a region of low water concentration through a selectively permeable membrane. osmosis requires a concentration gradient to occur.

Question 21

give the definition of active transport

Answer 21

the movement of molecules or ions across a cell membrane against a concentration gradient.

Question 22

how are molecules and ions transported during active transport?

Answer 22

they are moved by carrier proteins. the process requires energy because they are being moved against the concentration gradient, this energy is ATP and is produced during respiration.

Question 23

give an example of the importance of active transport in animal cells

Answer 23

the reabsorption of glucose from the kidney tubules back into the bloodstream, ensuring that glucose is not passed out through the urine.

Question 24

give an example of active transport in plants

Answer 24

some seaweeds and corals can accumulate iodine from sea water in their cells to a concentration hundreds of times greater than the surrounding water.

Question 25

what state does a plant cell become when placed in a solution with a higher concentration in the surroundings than in the cell?

Answer 25

Turgid

Question 26

what happens to an animal cell when it is placed in a solution of greater concentration than the cell?

Answer 26

it will eventually burst

Question 27

in mature animals which have stopped growing, what is the main purpose of cell division?

Answer 27

replace worn out cells and repair damaged tissue

Question 28

what is cell division also known as?

Answer 28

mitosis

Question 29

what determines the characteristics of an organism?

Answer 29

gene

Question 30

how many sets of matching chromosomes are in a human?

Answer 30

23 the diploid number is 46

Question 31

Explain the sequence of events in mitosis

Answer 31

1- nucleus containing long uncoiled chromosomes each doubling to form 2 identical chromatids
2- short coiled up chromosome (made of 2 chromatids)
3- chromosome attatched at equator
4- pair of identical chromatids separated and moving to opposite ‘poles’
5- nuclear membrane cytoplasm divides, separated chromatids now called chromosomes
6- two daughter cells each containing same number of chromosomes as original cell

Question 32

Explain the sequence of events in mitosis

Answer 32

1- nucleus containing long uncoiled chromosomes each doubling to form 2 identical chromatids
2- short coiled up chromosome (made of 2 chromatids)
3- chromosome attatched at equator
4- pair of identical chromatids separated and moving to opposite ‘poles’
5- nuclear membrane cytoplasm divides, separated chromatids now called chromosomes
6- two daughter cells each containing same number of chromosomes as original cell