last minute terms

Question 1

Define Transcription

Answer 1

Transcription occurs in the nucleus and is when a template strand of mRNA is produced from reading the DNA. Transcription must happen before translation as DNA does not leave the nucleus (due to its size and to reduce the risk of damage).

Question 2

Define Translation

Answer 2

Translation is the process which the ribosomes and tRNA operate together to assemble amino acids in the protein.

Question 3

Define facilitated diffusion

Answer 3

A form of passive transport where molecules move across the cell membrane through the membrane proteins

Question 4

Define osmosis

Answer 4

The movement of water across the membrane from an area of higher water concentration to lower water concentration.

Question 5

Define inhibitors

Answer 5

Inhibitors are compounds which modify the catalytic properties of the enzyme and, therefore, slow down the reaction rate, or in some cases, even stop the reaction

Question 6

Define cell membrane

Answer 6

Separates the interior of the cell from the outside environment

Question 7

Define chloroplast

Answer 7

A chloroplast is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cell

Question 8

Define mitocondria

Answer 8

Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell’s biochemical reactions.

Question 9

Define light dependant phase

Answer 9

Light energy is absorbed by the pigment chlorophyll. This light energy splits the water molecule into oxygen and hydrogen. Hydrogen ‘goes to the’ light-independent process, while oxygen is excreted as a waste product (via stomata on leaves).

Question 10

Define light independent phase

Answer 10

In the light independent phase, carbon dioxide and Hydrogen are joined together to create glucose. This phase does not require light

Question 11

Define aerobic respiration

Answer 11

Aerobic respiration occurs in the mitochondria.
Glucose + oxygen -> 36ATP + carbon dioxide + water

Question 12

Define anaerobic respiration

Answer 12

Anaerobic respiration occurs in the cytoplasm of the cell. It does not require oxygen. In most cases, during anaerobic respiration, glucose is broken down into carbon dioxide or ethanol.

Question 13

Purpose of cell cycle

Answer 13

The purpose of the cell cycle is to duplicate DNA in the chromosomes and then segregate the copies into two genetically identical daughter cells

Question 14

Cell cycle stages

Answer 14

G1 - cell increases in size
S - the cell copies its DNA
G2 - cell prepares to divide and chromosomes are checked for errors
Mitosis - cell divides resulting in two daughter cells that each have identical

Question 15

Define crossing over

Answer 15

Crossing over is the exchange of alleles between pairs of homologous chromosomes. It occurs during meiosis

Question 16

Define segregation

Answer 16

During meiosis, the two members of any pair of alleles segregate (separate) unchanged and are passed into different gametes

Question 17

Define fertilisation

Answer 17

Fertilisation is the fusing of an egg cell and a sperm cell to create offspring

Question 18

How does crossing over affect linked genes

Answer 18

Linked genes can be separated by crossing over (the exchange of alleles between homologous chromosomes), and this produces chromosomes that have different and / or new combinations of alleles. This increases genetic variation as these genes would normally be inherited together, but are separated to become unlinked gene/traits. e.g. red hair and freckles are typically inherited together but can be separated, meaning offspring could have freckles but no red hair or vice versa.

Question 19

Define gene pools

Answer 19

A gene pool refers to the the number of all the genes present in a reproducing population or species.

Question 20

Define gene flow

Answer 20

movement of individuals, and the genetic material they carry, from one population to another. (migration, emigration)

Question 21

Define natural selection

Answer 21

The process in which organisms with traits better suited to their environment tend to survive longer and therefore produce more offspring and pass on their alleles.

Question 22

Genetic drift

Answer 22

Genetic drift is the random change in allele frequency due to chance