unit 6

Protein synthesis

The process of reading the instructions in DNA to make a polypeptide

Polypeptide

A chain of many amino acids, can bind to others and fold into a protein.

DNA

instructions, located in nucleus, which can't leave

What does mRNA (messenger) do?

Copies instructions in DNA and carries these to the ribosomes in the cytoplasm

What does tRNA (transfer) do?

binds and carries specific amino acids to the ribosome

What does rRNA (ribosomal) do?

make up the ribosome

Purpose of transcription

Carry the code/instructions out of

the nucleus

Location of transcription

Nucleus

Transcription starts with

DNA

Transcription ends with

mRNA

First step of transcription

Unzip the gene that needs to be copied.

Second step of transcription

Use complementary base-pairing rules to match RNA

nucleotides with the exposed DNA nucleotides.

Third step of transcription

Release the completed mRNA molecule.

Fourth step of transcription

DNA zips back up and the mRNA leaves the nucleus

and enters the cytoplasm.

Genetic code

code of instructions for how to make

proteins

Codon

a set of

3 nucleotides on

the mRNA

Anticodon

"complementary" 3

nucleotides on

tRNA

Amino Acid

monomer

(building block)

for making

proteins, held

together by

peptide bonds

Purpose of translation

Read/follow the instructions carried

on the mRNA to make a polypeptide

Translation location

Ribosomes

What does translation start with?

mRNA

What does translation end with?

polypeptide

The first step of translation?

mRNA attaches to a ribosome.

The second step of translation

Ribosome reads the mRNA codons, starting at AUG.

The third step of translation

tRNAs act like taxis to pick up and drop off the amino acids that match with each codon.

The fourth step of translation

tRNAs continue to drop off a.a., and the ribosome binds the a.a. together with peptide bonds.

The fifth step of translation

When the "stop codon" is reached, the ribosome releases the completed polypeptide chain.

DNA replication nucleotides

A, T, C, and G

Transcription nucleotides

A, U, C, and G

Translation building blocks used

Amino acids

Is gene expression a highly regulated process?

yuh

Transcription factors

regulatory proteins that

control gene activity

Epigenetics

The study of changes in gene expression that

are heritable.

Mutation

a

change in a

DNA sequence.

Do epigenetics actually affect the DNA sequence?

No

Nucleic Acid

The macromolecule that holds our genetic

material

genes

sections of DNA that serve as the blueprint/instructions for making proteins

Two types of nucleic acid

DNA and RNA

Three parts of nucleotides

sugar, phosphate, nitrogen base

DNA structure

Double helix

DNA complementary base pairing rules

A's with T's C's with G's

RNA structure

Single strand

RNA base binds with DNA bases

A's with U's C's with G's

Chromosomes

tightly coiled strands of DNA

How many total chromosomes do humans have?

46 (23 from mom, 23 from dad)

DNA replication

Making an identical copy of DNA

When and where does DNA replication occur?

in the nucleus during the S Phase (Synthesis) of Interphase.

First step of DNA replication

Unzip the DNA

Second step of DNA replication

Enzymes help find complementary bases and bind

them according to base-pairing rules (A-T and C-G)

Third step of DNA replication

Two identical DNA molecules are formed, each with

an "old" strand and a "new" strand.

Why's DNA replication considered to be semi-conservative

because part of the molecule is

conserved/saved

Somatic cells

Body cells

- These are diploid (2n)

Gametes

Sex cells

- These are haploid (n)

Dipliod

2 full sets of chromosomes

- A set from mom and a set from dad

- Ex. In human somatic cells, 2n \= 46

Haploid

1 full set of chromosomes

- Only one set that is a combination of chromosomes from mom and dad

- Ex. Gametes \= egg and sperm, n \= 23

Autosome

Carry traits that make you who you are

Karyotype

diagram that shows the

number and visual appearance of the

chromosomes in a cell

sex chromosomes

Carry traits that make you who you are AND determine your biological sex

Meiosis

the process of cell division that makes

gametes in the gonads

Can sexual reproduction happen without meiosis?

No :)

Sexual reproduction

organisms that reproduce

sexually (like humans) fuse the genetic information

(gametes) from two parents to produce offspring

that are a genetic mixture of both parents.

Fertilization

the actual fusion of egg and sperm

to form a zygote.

Homologous chromosomes

chromosome pairs that

have the same types of

genes