Cell Division & Reproduction Flashcards
(19 cards)
What is the nucleus?
Contains genetic material in the form of 23 pairs of chromosomes.
What is a chromosome?
Long, coiled molecules of DNA.
They are always in pairs, one from each parent.
What is a gene?
A gene is a shorter piece of a chromosome that codes for a particular characteristic.
What is DNA?
A molecule that carries the genetic instructions for the living organism.
What is an allele?
Different versions of the same gene, which give different versions of a characteristic.
What are the complementary base pairing rules?
Adenine = Thymine (AT)
Guanine = Cytosine (GC)
What are genetic mutations?
Any change in DNA that will be reproduced when the DNA is copied. It can involve sections being missed out, extra genes being added, sections being copied twice etc.
What is asexual production?
Only one parent.
Clones of parent.
Advantages: only one parent needed, all offspring are clones
Disadvantage: no variation
What is sexual production?
2 parents.
Inherits mixture of features from both parents.
Variation in offspring.
Advantage: varied offspring so more chance for survival.
Disadvantage: requires two parents
What is mitosis?
To clone body cells.
1. Two pairs of chromosomes in a skin cell.
2. The chromosomes duplicate.
3. The chromosomes line up along the cell’s equator.
4. The chromosomes separate.
5. The cell splits into two to form two identical skin cells.
What is meiosis?
It takes place for the sole purpose of producing sex cells (gametes).
Prophase I: Two pairs of chromosomes in an ovary cell. The chromosomes duplicate.
Metaphase I: The homologous chromosomes line up along the cell’s equator.
Anaphase I: The chromosomes separate.
Telophase I: The cell splits into two producing cells with different chromosomes.
Pro-Anaphase II: Chromosomes separate again.
Telophase II: Four egg cells are formed.
What is germination?
It occurs when a new plant grows out from a seed.
All seed require water, oxygen and warmth for successful germination.
They also need minerals such as, nitrates, phosphates, & potassium compounds.
What is pollination?
The process of moving pollen from the anther to the stigma.
If it happens on the same plant, it is self-pollination.
If it happens on a different plant, it is cross-pollination.
Name the differences between wind-pollinated and insect-pollinated flowers.
Characteristic: Insect - Wind
Petals & Smell: large, brightly-coloured; sweet - small, dull; no scent
Nectar; Anther: yes; firm, inside flower - no; loose, outside flower
Pollen: less needed; sticky - more needed; light, dry, smooth
Stigma: inside flower; sticky - outside flower; sticky, netlike
What is the difference between DNA & RNA?
RNA is single-stranded.
RNA has the 4 bases A, G, C, & U (Uracil instead of Thymine).
What is protein synthesis?
Transcription: making RNA from DNA
Translation: making proteins from mRNA, ribosome from tRNA
What is transcription?
Takes place in nucleus where the DNA is turned into a mRNA molecule.
What is translation?
The process in which the mRNA is ‘read’ and translated into a protein.
It occurs on the ribosomes.
It involves another type of RNA molecule known as transfer RNA (tRNA).
What is the triplet code?
Each RNA triplet of three bases codes for one of the 20 amino acids. Several triplets can code for the same amino acid - it is degenerate.
