Biology CP Midterm Review

LARGE -------------------------- SMALL

Biosphere

Ecosystem

Organism

Cell

DNA /Genes

Scale of Biology

Domain is BROADEST category- 3 domains• ARCHAEA• BACTERIA• EUKARYA- more complex- eukayotic-

– 4 kingdoms• Protists

• Fungi

• Plants

• Animals– Invertebrates– Vertebrates

Mammals

DOMAINS of LIFE

Small, single celled, prokaryotic

Characteristics of Eukaryotic Cells

• Membrane-bound nucleus (contains DNA)

• Organelles in cytoplasm

• Larger, can be multicellular

cell membrane

organelles

nucleus

Eukaryotic Cells- Plants & Animals

ANIMAL cells- No cell wall- many small vacuoles

PLANT cells- Chloroplasts- Cell wall- 1 large vacuole

Characteristics of Prokaryotic Cells

• No nucleus or organelles

• DNA in cytoplasm

• Small, all are unicellular

cell membrane

organelles

nucleus

Structure of Cell Membrane

• FLUID MOSAIC MODEL

cell membrane

protein

cholesterol

proteincarbohydratechain

protein channel

Osmosis- SALT SUCKS

• Movement of WATER across selectively permeable membrane

Four groups of large Biomolecules

• Carbohydrates– Sugar (mono/disaccharide), starch/fiber

(polysacch)– Main source of body’s energy

• Lipids/fats/sterols– Make up membranes, used for energy

• Proteins– Structural building blocks, enzymes

• Nucleic Acids– DNA/RNA, stores genetic ‘code’

Enzymes = proteins that speed up specific reactions in cells

• Activation energy: “start up” energy to get a chemical reaction started

• Catalyst: anything that speeds up chemical reactions• Enzyme: special protein – catalyst in organisms

– Ex: sucrase, amylase– Anything with suffix -ase = enzyme

• Substrate: binds to the enzyme; must fit into active site– Ex: sucrose

• Active site: place (on enzyme) where the substrate fits– Lock and key

Cell Cycle

I. Interphase (90% time)1.) G1 phase- cell grows 2.) S phase- genetic material duplicates 3.) G2 phase- cell prepares to divide• DNA loosely packed as chromatin

II. Mitosis (10%) 4.) M phase (mitotic)- mitosis (PMAT) and

cytokinesis

Diploid (2n) vs. Haploid (n) Cells

•Body Cells

•Contain both homologous chromosomes

•Total = 46 chromosomes

(44 autosomes & 2 sex)

• Reproduce through mitosis

•Sex Cells (egg and sperm)

•Contain only one of the homologous chromosomes

•Total = 23 chromosomes

(22 autosomes & 1 sex)

• Made through meiosis

Meiosis results in 4 haploid gamete cells– Meiosis occurs in sex cells – Involves 2 cell Divisions*– Meiosis produces 4 gametes* which are

haploid (n) cells.

– Note: This picture Does not show

Chromosome #’s. Meiosis 1

Meiosis 2

4 haploid gametes

Parent Cell

During interphase

2n

2n

n n

n n nn

Mitosis vs. MeiosisMitosis and meiosis are types of nuclear division

that make different types of cells.

Mitosis makes more diploid (2n) cells

Meiosis occurs in sex cellsMitosis occurs in body cells

Meiosis produces gametes (haploid (n) cells)

DNA is composed of four types of nucleotides.

• DNA (polymer) is made up of a long chain of nucleotides (monomer).• Each nucleotide has three parts:

– phosphate group– Sugar (deoxyribose)– Nitrogenous base

There are 4 different

types of nucleotidesphosphate group

deoxyribose (sugar)

nitrogenousbase

Quick Review…• GENE= unit of heritable information in DNA

(region with coding for a trait)

If nucleotides are the building blocks of DNA/RNA, what are the building blocks of PROTEINS??

• RNA vs. DNA…

GENE ANIMATION

– RNA has a ribose sugar.– RNA has uracil instead of thymine.– RNA is a single-stranded structure.

• REPLICATION: Exact copy of DNA is made using each half as a template (in nucleus)

• TRANSCRIPTION: Converting DNA sequence (gene) into a single stranded mRNA molecule (in nucleus)

• TRANSLATION: Converting mRNA message into a polypeptide/protein (in cytoplasm, done by ribosomes)

DNA Replication TRANSLATION

DNA RNA PROTEINS

TRANSCRIPTION

Genetics Basics1. ALLELE = alternative forms of a gene… ex. Brown

hair allele, black hair allele (gene is for hair color)

2. You have TWO alleles for each character- one came from your mom, one from your dad

3. Each gamete carries ONE allele (in MEIOSIS, the parent cell splits its genetic information in half… if mom was Bb, each egg will get either B or b)

4. GENOTYPE = Ee (heterozygous) … determined by genetic code/genes/DNA

PHENOTYPE= Red eared… physical expression, based on PROTEINS

Dihybrid Cross- HOW TOStep 1- Determine Genotype of parents

CCPP  X   ccPp

Step 2- Determine different combinations of parent alleles (USE FOIL)CCPP … F=CP or O=CP or I=CP or L=CP

ccPp … F=cP or O=cp or I=cP or L=cp

Step 3- Line pairs up along 4x4 P-squareEach offspring will have 4 letters, describe with

two words for phenotype!

Intermediate/Incomplete and Codominance

• Keys to remember:– Mixed offspring will be HETEROZYGOUS– Both letters are capitalized– Denote with superscripted letters (CW or LT etc)

• INTERMEDIATE/INCOMPLETE- Blend of parent traits

CRCR (red) x CWCW (White) = CRCW (Pink)

• CODOMINANCE- Both traits show

CBCB (black) x CWCW (White) = CBCW (stripes)

Many genes may interact to produce one trait.

• Polygenic traits = produced by two or more genes

• Ex.- Eye, skin color• Wide range of

variationOrder of dominance: brown > green > blue.

Sex-Linked Traits• Gene located on sex chromosome, usually the X

… Eye color in fruit flies (Red = R, white=r)• Females (XX) carry two copies of the gene, may

carry the trait, but not show it (XRXr), will have white eyes ONLY if she has copies (XrXr)

• Males (XY) carry one copy (no other X to ‘hide’ it), so they will either HAVE IT (XrY ) or NOT HAVE IT (XRY)

*Males only have to inherit ONE copy, whereas females must inherit 2!*

Disorders as SEX-LINKED Traits

• Usually located on X chromosome

• More common in males… Colorblindness

NOTICE:

- No male carriers

- More common in

Males than females

Principle of segregation

during gamete formation, a particular allele for one character can be paired with either allele of another character (useful for dihybrid crosses, FOIL)

Principle of independent assortment

genes are located on chromosomes, behavior (separation) of chromosomes during meiosis and fertilization accounts for inheritance patterns

Chromosome theory of

inheritance

the two alleles for a character segregate (or separate) during meiosis, so each gamete carries only one allele for each character

Disorders as DOMINANT Traits• Fewer of these than Recessively inherited

disorders, typically HETEROZYGOUS• Not so bad: polydactyly• Not Hot: Achondroplasia, Huntington’s disease

LETHAL DOMINANT alleles- embryos that are homozygous are typically miscarried (do not survive)

*those with disorder are typically Heterozygous