CST ReviewCST Review

Genetics I.Genetics I.

Standards:Standards: BI5. a. BI5. a. Students know Students know the general structures and the general structures and

functions of DNA, RNA, and protein.functions of DNA, RNA, and protein. BI1. d. BI1. d. Students know Students know the central dogma of molecular the central dogma of molecular

biology outlines the flow of information from transcription biology outlines the flow of information from transcription of ribonucleic acid (RNA) in the nucleus to translation of of ribonucleic acid (RNA) in the nucleus to translation of proteins on ribosomes in the cytoplasm. proteins on ribosomes in the cytoplasm.

BI2. a. BI2. a. Students know Students know meiosis is an early step in sexual meiosis is an early step in sexual reproduction in which the pairs of chromosomes reproduction in which the pairs of chromosomes separate and segregate randomly during cell division to separate and segregate randomly during cell division to produce gametes containing one chromosome of each produce gametes containing one chromosome of each type.type.

BI2. b. BI2. b. Students know Students know only certain cells in a multicellular only certain cells in a multicellular organism undergo meiosis. organism undergo meiosis.

Standard SummariesStandard Summaries BI5. a. BI5. a. The structures and jobs of DNA, RNA, and The structures and jobs of DNA, RNA, and

protein.protein. BI1. d. BI1. d. The central dogma-Genetic instructions are The central dogma-Genetic instructions are

transcribed (copied) into mRNA in the nucleus, then the transcribed (copied) into mRNA in the nucleus, then the genetic instructions are translated into proteins on genetic instructions are translated into proteins on ribosomes in the cytoplasm. ribosomes in the cytoplasm.

BI2. a. BI2. a. Meiosis produces sex cells, chromosomes pairs Meiosis produces sex cells, chromosomes pairs are separated randomly during this process, producing are separated randomly during this process, producing gametes containing one chromosome of each type gametes containing one chromosome of each type (haploid).(haploid).

BI2. b. BI2. b. Only sex cells (gametes) are produced meiosis. Only sex cells (gametes) are produced meiosis.

Objectives:Objectives:explain the genetic factors that influence explain the genetic factors that influence

the way we look.the way we look. recognize that DNA contains the genetic recognize that DNA contains the genetic

information that determines the way we information that determines the way we look. look.

explain the structure and function of DNA.explain the structure and function of DNA.understand the general pathways by which understand the general pathways by which

ribosomes make proteins.ribosomes make proteins.

Part I. DNA Basics and The Central Part I. DNA Basics and The Central DogmaDogma

DNA BasicsDNA Basics

Double helix=twisted ladderDouble helix=twisted ladderChromosomes=chains of DNA and Chromosomes=chains of DNA and

proteins.proteins.Contains your genetic info (instructions to Contains your genetic info (instructions to

make proteins)make proteins)Sequences of DNA=GenesSequences of DNA=GenesGenes=codes for proteins=instructions for Genes=codes for proteins=instructions for

traits traits

What is the central dogma?What is the central dogma?

The central dogma describes the flow of The central dogma describes the flow of information from DNA to RNA to proteins.information from DNA to RNA to proteins.

Central Dogma-Protein SynthesisCentral Dogma-Protein Synthesis

DNA is transcribed to mRNA in the DNA is transcribed to mRNA in the nucleus nucleus (transcription)(transcription)

mRNA carries the genetic information into mRNA carries the genetic information into the cytoplasmthe cytoplasm

Proteins are assembled at the ribosomes Proteins are assembled at the ribosomes based on the based on the ““codecode”” carried by the mRNA carried by the mRNA (translation)(translation)

How does your DNA determine How does your DNA determine what you look like? I.what you look like? I.

Your traits are Your traits are inheritedinherited from your parents. from your parents. This means DNA is passed on from This means DNA is passed on from generation to generation in the form of generation to generation in the form of chromosomes. The codes of the DNA chromosomes. The codes of the DNA called genes have the instructions for your called genes have the instructions for your traits. traits.

Part II. Cell Cycles and Inheritance Part II. Cell Cycles and Inheritance of Traitsof Traits

The Cell Cycle-DNA is copied and The Cell Cycle-DNA is copied and the cell divides (Mitosis)the cell divides (Mitosis)

DNADNA

DNA contains the info to make cells, and DNA contains the info to make cells, and we are made of cells…then DNA we are made of cells…then DNA determines our cellular and molecular determines our cellular and molecular make-up which determines what we look make-up which determines what we look like.like.

How does your DNA determine How does your DNA determine what you look like?II.what you look like?II.

Your traits are Your traits are inheritedinherited from your parents. from your parents. This means DNA is passed on from This means DNA is passed on from generation to generation in the form of generation to generation in the form of chromosomes. The codes of the DNA chromosomes. The codes of the DNA called genes have the instructions for your called genes have the instructions for your traits. You inherit one copy of each gene traits. You inherit one copy of each gene from each parent giving you a certain from each parent giving you a certain genetic make-up that determines your genetic make-up that determines your physical make-up.physical make-up.

Where does our DNA come from?Where does our DNA come from?

½ your ½ your chromosomeschromosomes from your momma from your momma

½ your ½ your chromsomeschromsomes from big poppa from big poppa

You have 23 pairs of chromosomes (46 You have 23 pairs of chromosomes (46 total)total)

How does the DNA get from our How does the DNA get from our parents to us?parents to us?

Sex cells are produced by our parents Sex cells are produced by our parents (meiosis) and then fuse together during (meiosis) and then fuse together during fertilization to combine their genetic fertilization to combine their genetic information (chromosomes).information (chromosomes).

ThatThat’’s why we look like our parents, but s why we look like our parents, but not exactly like our parents.not exactly like our parents.

FertilizationFertilization