BIOL 101 - Exam 2

What is a chromosome?

it’s a bunch of DNA wrapped up in each other (the whole x)

How many chromatids are in 1 chromosome?

1 chromosome has 2 chromatids

What is a centromere?

the center of the chromosomes (holds the chromatids together)

What is a chromatid?

It’s 1 strand of DNA

What is mitosis?

cell division that produces identical copies of a cell.

Note: Organisms that reproduce asexually use mitosis to make identical copies of themselves. Multicellular organisms use mitosis to grow and repair damaged cells.

What are the phases in the cell cycle?

1. Interphase

2. Mitosis

What are the phases in the interphase of mitosis?

1. G1 phase - longest phase that the cell is in.

2. S phase

3. G2 phase

What are the 4 phases of mitosis?

• Prophase

• Metaphase

• Anaphase

• Telophase

Then cytokinesis (the “5th phase”) occurs.

What is happening during the prophase of mitosis?

What is the chromosome doing?

• Chromosomes are condensing (becoming an X shape)

What is the spindle fibers doing?

• Spindle fibers are forming from the centrioles

  • (the lines coming out of the cylinders [centrioles])

What is the nucleus envelope doing?

• Nuclear envelope is disappearing

  • The dotted circle

What is happening during the metaphase (middle, we fishing) of mitosis?

What is the chromosome doing?

• Chromosomes are lining up in the middle of the cell

What is the spindle fibers doing?

• Spindle fibers are attaching to the centromere (the middle of the chromosomes) of the chromosome

What is the nucleus envelope doing?

• Nuclear envelope is not present atm

What is happening during the anaphase (away/apart, we reeling in the fish) of mitosis?

What is the chromosome doing?

• Chromosomes are pulled apart

What is the spindle fibers doing?

• Spindle fibers are shortening (pulling the fishing line back)

What is the nucleus envelope doing?

• Nuclear envelope is still not present

What is happening during the telophase of mitosis?

What is the chromosome doing?

• Chromosomes are decondensing

What is the spindle fibers doing?

• Spindle fibers are disappearing (they’re going back in the centriole)

What is the nucleus envelope doing?

• Nuclear envelope is coming back (reforming)

What is happening during the cytokinesis of mitosis?

2 daughters are forming

• No need to ask the three q’s anymore

What do plant cells do differently for mitosis?

Even though they don’t have centrioles, they still form spindle fibers to arrange the chromosines and pull apart the sister chromatids.

During cytokinesis, vesicles line up along the center of the plant cell to form a cell plate. The cell plate is a new cell wall. The cell plate grows across the cell, forming two plant cells, each with its own cell membrane and cell wall.

What do prokaryotic cells do for cell division?

Binary fission

• Same theme of process but no pro phase, metaphase, etc. just splitting the cell

What are the defects of cell division?

• Activates the proteins (coded by proto-oncogenes) required for cell growth when they should be on

• Prevents tumor suppressor genes from shutting down the cell cycle

What does diploid and haploid mean?

Diploid (2n) - it means you have two sets of chromosomes

Haploid (n) - one set of chromosomes

What does homologous chromosomes and gametes mean?

Homologous Chromosomes - chromosomes that contain the same pieces of genetic information

Gametes - sex cells (egg and sperm)

What is the difference in meiosis when compared to mitosis?

• Results in 4 different daughter cells

• Results in haploid cells

• Involves gametes (sex cells)

How many stages are there in meiosis?

2, meiosis I and meiosis II

What happens during meiosis I?

the pairs of chromosomes separate. The product is TWO haploid cells

• It deals with homologous chromosomes

What happens during meiosis II?

the two daughter cells divide. This results in FOUR haploid cells

• It deals with sister chromatids

What are the diff in mitosis and meiosis?

• Mitosis creates 2 daughter cells and meiosis creates 4

• Mitosis creates identical daughter cells, meiosis creates unique

• Mitosis happens with solmatic (body, liver, stomach, etc.), meiosis deals with gametes (sex) cell

• Mitosis does asexual reproduction, meiosis does sexual reproduction

• mitosis deals with one division, meiosis deals with 2 divisions

• mitosis main purpose is for growth and repair, meiosis is for reproduction

What is independent assortment?

chromosome pairs randomly align and separate, ensuring that genes for different traits (like eye color and hair color) are inherited independently of one another

•During metaphase I, homologous pairs of chromosomes line up along the center of the cell. The pairs (and pairs of alleles) separate during anaphase I.

•The chance that an allele will separate and sort into a daughter cell with other alleles on different chromosomes is completely random. 

• Happens during metaphase 1

What is crossing over?

When the chromosomes pair up, the sister chromatids of homologous chromosomes can cross. When the sister chromatids cross each other, they exchange portions of their genetic information. 

What is nondisjunction?

• Nondisjunction is the failure of chromosomes to separate properly during meiosis.

• Nondisjunction most commonly occurs when homologous chromosomes do not separate during meiosis I.

• Sometimes nondisjunction occurs when sister chromatids do not separate during meiosis II.

What causes down syndrome?

Its caused by nondisjunction of chromosome 21

What is a mutation?

Any permanent change in an organism’s DNA

• Change in genotype (genes) = Change in phenotype (physical traits)

What are the 2 types of mutations?

Point Mutation: alters one or a small number of base pairs (strand of DNA)

• So alters one or a couple strands of DNA

• Like a typo in the instructions, not that big of a deal

Chromosomal Mutation: affects the entire chromosome

• Typical more serious effects

What are the 3 types of point mutations and its subtypes?

Substitution

• Silent

• Missense

• Nonsense

Insertion

• Nonsense

• Frameshift

Deletion

• Nonsense

• Frameshift

What are the effects of missense?

changes the identity (size, piece, color) of an amino acid (different protein)

What are the effects of silent?

Does not change the amino acid (same exact protein)

What are the effects of nonsense?

Amino acid changes into a stop codon; premature termination (stopping the process early)

What are the types of mutations?

• Beneficial - increases the fitness (ability to reproduce) of the organism

• Neutral - no effect on fitness; typically a silent mutation

• Deleterious - decreases the fitness of the organism

What are chromosomal mutations?

Large scale mutation that can change either the structure or the number of chromosomes

Can cause aneuploidy or polyploidy

Does not change DNA sequences but can cause permanent damage by altering the number of copies of each sequence

Which chromosome is which? Deletion, duplication, inversion, translocation

What is genetics?

The study of heredity, which is a biological process where a parent passes certain genes onto their offspring.

Genes are inherited from both parents through sexual reproduction. MEIOSIS

These genes express specific traits or characteristics.

Who was the father of modern genetics?

Gregor mendel

• he was a monk from austria

• he discovered the basic principles of heredity

• he experimented on pea plants and showed that their traits follow a particular pattern

Where are chromosomes found?

In the inside of the nucleus of a cell (they carry the genes)

• Genes are segments of DNA on a chromosome and are responsible for inherited traits.

What does geno/pheno type mean?

Genotype - the genetic makeup of an organism. (it’s just your genes)

Phenotype – the appearance of an organism based on its genotype, plus environmental factors (physical appearance)

What are alleles?

the flavors of the gene, like diff types of ice cream

• Variants (differences) in a gene

• Occurs on a fixed spot on a chromosome

• In humans an allele might indicate blood type, colorblindness, or many other traits.

Example:

• gene: eye color

• alleles: brown, blue, hazel

In a pedigree chart, how is a dominant trait introduced to the gene pool?

For dominant traits, individuals with the trait will ALWAYS have a parent with the trait

Note: Often difficult or impossible to determine whether a trait is dominant or recessive based on pattern

What does codominance and incomplete dominance mean?

Codominance is both traits show up, so red & white.

Incomplete is mixing the traits together, so pink.

Note: Since the heterozygous genotypes have a unique phenotype for both incomplete dominance & codominance, there are NEVER genotypes with unknown alleles

idk, sorry its about x/y llinked traits

Use Punnett squares to determine that some patterns are impossible

What does ecto/endo therm mean?

Ectotherm = organisms that rely on outside temperature to regulate body temp (like reptiles)

• Ecto means outside, therm means temperature

Endotherm = organisms that can regulate their body temp internally

• Endo means inside, therm means temperature

What does negative/positive feedback mean?

Negative feedback - response of your body to return to normal or homeostasis (sweating or shivering)

Positive feedback = response of your body to increase effect, away from normal or homeostasis (giving birth)

What are the functions and main parts of the nervous system?

Functions

• Controls all body’s functions

• Senses and recognizes information from inside and outside of the body 

Main Parts

• Brain

• Nerves (peripheral and autonomic)

• Spinal cord

What are the functions and main parts of the skeletal system?

Function:

• Helps support your body parts

• Helps support your body during movement

• Helps protect your major organs:

  • Skull protects the brain

  • Sternum and ribs protects the heart and lungs

  • Vertebra protect the spinal cord

Main parts:

• Bones

• Cartilage

• Connective Tissue (joints, tendons, ligaments)

What are the functions and main parts of the muscular system?

Function

• Helps you move

• Moves materials through the body

• Works with the skeletal system

Main parts

• Muscles

• Tendons 

• Ligaments 

• Muscles in organs

What are the 3 types of muscles found in the body?

• Cardiac – found in the heart 

• Skeletal - attaches to the bones

• Smooth – lines organs and vessels. 

What are the functions and main parts of the cardiovascular system?

Function

• Carries blood and nutrients to the cells of the body

• Carries waste away from the cells, such as carbon dioxide.

Main Parts

• Blood Vessels

• Heart

• Blood

What do arteries, veins, & capillaries do?

• Arteries help carry oxygenated blood away from the heart (to the rest of your body)

• Veins carry deoxygenated blood toward the heart (already circulated around the body)

• Capillaries are tiny blood vessels that connect arteries and veins. Gas exchange takes place here.

What do red/white blood cells, platelets, and plasma do?

• Red Blood Cells: carry oxygen around the body

• White Blood Cells: works with the immune system to fight off infections

• Platelets: stops bleeding by clumping on the open wound 

• Plasma: helps maintain blood pressure and volume

What are the functions and main parts of the respiratory system?

• Function

  • Puts oxygen into the body & removes carbon dioxide

• Main parts

  • Nose

  • Nasal Passages

  • Pharynx 

  • Larynx 

  • Bronchi

  • Bronchioles

  • Alveoli

  • Lungs

What are the functions and main parts of the digestive system?

Function

• Takes food & breaks it down into nutrients the body needs 

Main parts:

• Mouth

• Stomach

• Liver: produces bile

• Pancreas: secretes insulin

• Small intestines: absorbs nutrients

• Large intestines: reabsorbs water 

• Rectum 

What enzyme is associated with the mouth and the stomach and what do they digest?

Mouth - amylase, digests carbs

Stomach - pepsin, digests proteins

What enzyme is associated with the pancreas and the small intestine and what do they digest?

pancreas - lipase, digests fats

small intestine - lactase, digests lactose (dairy products)

What are the functions and main parts of the urinary system?

Functions

• Removes wastes from blood

• Removes harmful substances from blood

• Regulates body fluids 

Main Parts

• Kidneys: filters blood

• Ureter: connects kidneys to urinary bladder

• Urinary bladder: stores urine

• Urethra: Expels urine

What are the functions and main parts of the endocrine system?

Functions

• Helps  control and regulate different body processes through release of hormones

Main Parts

• Endocrine Glands

  • Pituitary Gland

  • Thyroid Gland

  • Parathyroid gland 

  • Adrenal: epinephrine. norepinephrine

  • Pancreas: insulin and glucagon

What is 1?

the right atrium

What is 2?

the left atrium

What is 3 & 4?

3 is the right ventricle and 4 is the left ventricle