SBI3U exam review

chromosomes

a package of DNA containing part or all of the genetic material of an organism

zygote

a fertilized egg cell

DNA

• aka deoxyribonucleic acid

• made up of nucleotides

DNA is classified as a protein

yes

centromere

it links a pair of sister chromatids together during cell division

nucleotide

the building blocks that make up RNA and DNA

chromatin

• made up of dna & histone proteins

• found during interphase of the cell cycle

tetrad

a pair of chromosomes

What is the complementary base pairing rule

• Adenine (A) bonds with Thymine (T)

• Cytosine (C) bonds with Guanine (G)

what is hydrogen bonding

a type of chemical bond that weakly attaches a molecule to another molecule

how many H-bonds are between A & T

2 hydrogen bonds

how many h-bonds are between C & G

3 hydrogen bonds

what is a gene

a piece of heredity material that is passed on from parent to offspring

what is an allele

a version of a gene at a particular position on a chromosome

what is heredity

the process of passing traits from parents to offspring

what is homologous chromosomes

a pair of chromosomes w/ the same type of genes

haploid cells (n)

• a cell w/ a single set of chromosomes

• humans sex cells have 23 chromosomes

diploid cells (2n)

• a cell that has 2 complete sets of chromosomes

• that # for humans is 46 chromosomes

autosomal chromosome

any chromosome that is not a sex chromosome

sex chromosome

Chromosomes that determine a individual's biological sex

somatic cells

• any cell that is not a sex cell

• are also diploid cells

gametes (sex cells)

• the reproductive cells of any animal or plant

• humans only have 23 chromosomes in their sex cells

• are also haploid cells

stages of mitosis

1. Interphase (G1,S, G2)

2. Prophase

3. Metaphase

4. Anaphase

5. Telophase

purpose of mitosis

is cell divison ; for a mother cell to produce 2 daughter cells in the end

total # of chromosome for a human cell at the prophase stage of mitosis

46 chromosomes

the "n" description of the cell at interphase

2n

total # of chromosomes for a human cell at the prophase stage of mitosis

46 chromosomes

the "n" description of the cell at prophase

2×2n

total # of chromosome for a human cell at the end of the telophase stage of mitosis

46 chromosomes

the "n" description of the cell at the end of telophase

2n

where does mitosis occur

in somatic cells

G1 phase of Interphase

• cell does most of its growing; making it take in more nutrients

• DNA is spread throughout the nucleus as chromatin

• cell increases in size

• cell has 2n diffuse chromosomes (diploid)

S Phase (synthesis phase) of Interphase

• cell continues to grow

• the diffuse chromosome duplicates, producing a 2x2n # of diffuse chromosomes

G2 phase of Interphase

• cell has 2x2 n chromosomes within the nucleus

prophase

• nuclear membrane dissolves

• chromatin condenses into chromosome, each w/ 2 sister chromatinds attached by a centomere

• spindle fibers & centrioles assemble

• centrioles move to the poles of the cell

• 2x2n

what is meiosis

a special cell division that involves the production of reproductive cells

purpose of meiosis

to produce sex cells (sperms & eggs) that have half the genetic information of somatic cells

stages of meiosis

In meiosis I

• Prophase I

• Metaphase I

• Anaphase I

• Telophase I

In meiosis II

• Prophase II

• Metaphase II

• Anaphase II

• Telophase II

where does meiosis occur

in sex cells

synapsis

when 2 duplicated homologous chromosomes line up side by side

non-disjunction mistakes

when homologous chromosome fail to separate properly during cell division

mistakes during crossing over

• duplication

• deletion

• inversion

• translocation

duplication

when one chromosome ends up with two copies of a gene

deletion

the other chromosome would have no copies of that gene

inversion

the gene order on a chromosome switches

translocation

a gene from one chromosome ends up on a non-homologous chromosome

aneuploidy

the presence of an abnormal # of chromosomes in a cell

polyploidy

cells that have more than 2 sets of homologous chromosomes

gametogenesis

the process where diploid gametes undergo meiosis to produce haploid gametes

polar body

a useless cell formed during oogenesis; it has chromosomes, but not much else

do all ovulated oocytes finish meiosis

oocytes only finish meiosis if they become fertilized

name of each cell that enters the body during spermatogenesis

spermatocyte

name of the cells that enter the body during oogenesis

oocyte

who determines the gender of a zygote

the father

blood type A+ can receive blood from

A+, A-, O+, O-

blood type A - can receive blood from

A-, O-

the antibodies present in blood type A’s plasma

Anti-B

the antigens present on type A's red blood cells

A antigen

blood type B + can receive blood from

B+, B-, O+, O-

blood type B- can receive blood from

B-, O-

the antibodies present in type B's plasma

Anti-A

the antigens present on type B's RBCs

B antigen

AB+ can receive blood from

all blood types

AB- can receive blood from

AB-, A -, B-, O-

the antibodies present in type AB's plasma

none

the antigens found on type AB'S RBCs

A & B antigen

O+ can receive blood from

O+, O-

O- can receive blood from

O-

the antibodies found in type O's plasma

A & B antibodies

the antigens found on type O's RBCs

no antigens

the universal blood recipient

type AB+

the universal blood donor

type O-

8 different types of blood

• A+

• A-

• B+

• B-

• AB+

• AB-

• O+

• O-

Rhogram shot

A preventive treatment given to Rh-negative mothers during and after pregnancy to prevent Rh incompatibility with Rh-positive babies.

Rh Incompatibility

A medical condition that occurs when an Rh-negative mother is pregnant with an Rh-positive baby, leading to potential complications.

What is an antigen?

a foreign substance that triggers an immune response, typically a foreign molecule that is recognized as harmful by the immune system.

where are antigens located

on the surface of RBCs

antibody

Y-shaped protein molecule in the blood plasma

purpose of antibodies

to identify and neutralize harmful invaders. antibodies are able to recognize a specific foreign molecule (antigen)

Rh factor is also known as

the rhesus factor

what is the rhesus factor

a protein marker in the blood

people who don't carry the Rh protein are called

Rh-

people who do carry the Rh protein are called

Rh+

Rh+ is

dominant

Rh- is

recessive

over 90% of the world is

Rh-

agglutination

clumping of red blood cells in response to antibodies fending off foreign materials

white blood cells

the defense system of the body; responsible for protecting against harmful, foreign invaders like parasites, viruses, bacteria

red blood cells

responsible for transport of oxygen & carbon dioxide between lungs and other tissues

law of segregation

states that alleles are separated during gamete formation

How does meiosis ensure the law of segregation?

During meiosis, homologous chromosomes are separated into different gametes, ensuring that each gamete receives only one allele for each gene, thus upholding the law of segregation.

law of independent assortment

states that genes for different traits segregate independently of one another during the formation of gametes

How does meiosis ensure the law of independent assortment?

During meiosis, genes for different traits segregate independently because homologous chromosomes align randomly along the metaphase plate, leading to various combinations in gametes.

law of dominance

The dominant allele's trait will mask the effect of the recessive allele in a heterozygous genotype.

heterozygous

having 2 different alleles of a particular gene (ex. Ee)

homozygous dominant

a genotype where an individual inherits 2 copies of a dominant gene ( Ex. EE )

homozygous recessive

a genotype where an individual has 2 copies of a recessive gene (ex.ee)

P generation

parental generation

F1 generation

first filial generation, the kids

F2 generation

second filial generation, the grandkids