DNA & RNA Flashcards
Ch 15
Definition of heredity?
the passing on of features from parents to offspring by means of genes.
What’s heredity also called?
genetic inheritance.
Name 3 features that humans inherit.
- number of fingers
- production of nails
- ability to form tears
Name 3 features that plants inherit.
- number of petals
- colour of petals
- shape of the leaves
Definition of a gene?
is a section of DNA that codes for the production of a protein.
Genes are the units of what?
inheritary.
Definition of gene expression?
the way in which the genetic information in a gene is decoded in the cell and used to make a protein.
Name the biologically active in identifies each of which contains only one type of nuclei acid.
viruses
2 locations where RNA is present but not DNA in eukaryotic cells.
cytoplasm and ribosomes
What do genes make, which do what?
Make amino acids which stick together in a certain order making a protein.
Definition of characteristics?
traits of features that are inherited genetically.
Chromosomes are composed of?
Protein and DNA
What’s the protein responsible for in chromosomes?
holding the DNA in a tightly packed configuration so it can fit in nucleus.
What percent of DNA present is used for coding proteins? The rest of the DNA is called?
3%,
Non-coding: “junk DNA”
What’s non-coding DNA?
Has genetic instructions that do not produce a protein.
Non-coding DNA is of two places: (where?)
- some occurs between genes
- some occurs within genes
Where are chromosomes found?
nucleus
When chromosomes aren’t dividing they?
form a long thread-like chromatin
DNA stands for?
deoxyribonucleic acid
Where is DNA always only found and sometimes found?
always only: nucleus
sometimes: mitochondria and chloroplasts
The four bases/chemicals used in DNA are?
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
Each of the four DNA bases can only join/bond with one other, which go with which?
A joins with T
G joins with C
( At the giants causeway)
A joining with T = how many hydrogen?
2
G joining with C = how many hydrogen?
3
Strands of DNA held together by?
complementary bases
What’s the genetic code?
The instruction to form a protein.
Up to how many different types of amino acids are used in proteins?
20
A sequence of three bases in DNA (or RNA) that act as a code for an amino acid.
triplet/codon
Whats a triplet/codon?
A sequence of three bases in DNA (or RNA) that act as a code for an amino acid.
Where and when does DNA replication take place?
In nucleus during interphase
Give 5 steps of DNA replication.
- during interphase the DNA double helix uncoils.
- an enzyme breaks the hydrogen bond between base pairs and the two DNA strands separate.
- DNA bases from cytoplasm enter nucleus and attach to exposed complementary DNA bases on the strand.
- each strand is half old, half new and each strand is an exact copy of the original DNA strand.
- all DNA strands rewind up to form a double helix shape.
Significance of DNA replication?
DNA is able to produce exact copies of itself.
What’s DNA profiling?
a method of making a unique pattern of bands from the DNA of a person.
Give the involved 4 steps for method of preparing a DNA profile?
- The DNA is released from cells which isolated.
- The DNA is cut into fragments of different lengths, restricting enzymes.
- The DNA fragments are separated according to their sizes.
- The patterns produced by the fragments are compared or analysed.
How is the isolated DNA cut into fragments during DNA profiling?
Using special enzymes called restriction enzymes.
What’s forensic medicine?
the way in which medical knowledge is used in legal situations.
Name some biological materials that can be collected and profile prepared (from a crime scene).
blood, hairs with root, saliva.
Name two applications of DNA profiles.
crime and medical
What’s genetic screening?
DNA is tested for a presence or absence of a particular gene.
Name a disorder you can genetically screen/identify.
sickle cell anaemia (cystic fibrosis)
Genetic screening may cause?
ethical problems
What does RNA stand for?
ribonucleic acid
Comment on structure of RNA.
single stranded
RNA is based on the sugar ___?
ribose
Where’s RNA found?
cytoplasm and nucleus
Give 3 structural differences between RNA and DNA.
- DNA contains sugar deoxyribose, RNA contains ribose.
- DNA bases are AT GC (thymine), RNA has AU GC (uracil).
- DNA is double stranded (double helix), RNA is single stranded.
Definition of transcription?
making of mRNA using a strand of DNA as a template.
Definition of translation?
the conversion of a sequence of genetic bases on messenger RNA into a sequence of amino acids.
Where does transcription take place?
nucleus
Distinguish between purines and pyrimidines?
Purines are Adenine (A) and Guanine (G).
Pyrimidines are Thymine (T) and Cytosine (C).
The forces holding the baes together are called?
hydrogen bonds
Name two people who discovered DNA structure.
Watson and Crick
Watson and Crick discovered?
structure of DNA
What’s an anticodon?
a sequence of three bases (triplet) on tRNA that are complementary to a sequence of three bases on mRNA
Ribosomes are made up of?
ribosomal RNA (rRNA) and protein
Each tRNA carries?
anticodon
Name three types of RNA and function.
mRNA (messenger)
tRNA (transfer)
rRNA (ribosomal)