Biology exam 2023

lateral

toward the side

medial

toward the midline

proximal

near a point of reference

distal

away from a point of reference

define hormone

A chemical released in 1 part of the body and affects cells of a different part of the body, a “messenger”

What is the function of the endocrine system?

To deliver “messages” throughout the body

What is the difference between exocrine and endocrine glands?

Exocrine: releases secretions through ducts. Endocrine: releases secretions through the bloodstream

Give 1 example of an exocrine gland.

Sweat glands, tear glands, digestives juices being released from various glands

pineal gland

Releases melatonin, which regulates our daily sleep/wake cycle. Melatonin makes us sleepy!

ovaries

Produces estrogen (responsible for egg development and the formation of the physical characteristics associated with puberty) and progesterone (prepares uterus for pregnancy)

testes

Produces testosterone (sperm production and the formation of the physical characteristics associated with puberty)

Explain how the pancreas maintains homeostasis.

When blood sugar levels are too high, the pancreas secretes insulin. Insulin stimulates liver and muscles to store excess glucose as glycogen. When blood sugar levels are too low, the pancreas secretes glucagon. Glucagon stimulates liver and muscles to break down glycogen and release glucose back into the blood.

nose and mouth

Warms, moistens and filters the air we breathe in.

epiglottis

Covers the entrance to the trachea when we are swallowing

Larynx (voicebox)

Muscles pull vocal cords together and air moving between them produces sound

Trachea (windpipe)

Connects larynx to bronchi; has cells with cilia (“hairs”) to filter air

Diaphragm

Large, flat, thin muscle that is between heart and liver and is involved in breathing.

Where does gas exchange take place?

Between capillaries and the alveoli (air sacs), which are grouped into clusters that look like grapes; a delicate network of thin-walled capillaries surrounds each alveolus.

Explain how the diaphragm moves when we inhale and exhale.

When we inhale, the diaphragm moves down to open up the chest cavity; the rib cage rises. When we exhale, the diaphragm moves up to push air out of the lungs; rib cage lowers.

What organs does the circulatory system include?

Heart, blood vessels and blood

The heart is enclosed in a protective sac of tissue called the \____

pericardium

Oxygen-rich blood from the lungs (where carbon dioxide was exchanged for oxygen) flows into the left side of the heart and is pumped to the rest of the body. This is called the \______________circulation pathway.

systemic

Blood that returns to the right side of the heart is oxygen-poor because\________. The cycle starts again when this blood goes to the lungs.

cells have already absorbed the oxygen

why are valves important in the heart

they keep blood moving in the heart in only 1 direction

What is the function of the digestive system?

Convert food into simpler molecules that the cells can use.

Pharynx (throat)

Passageway for food, drink and air

Salivary glands

Create saliva, which contains enzymes to start breaking down food in the mouth.

Esophagus

Connects the mouth to the stomach (contracts to help guide food down to stomach – this is called peristalsis)

Stomach

A large muscular sac that contains digestive enzymes to break down food

Small intestine

Most chemical digestion takes place here; where nutrients are absorbed from food

Large intestine (colon)

Retains excess water; develops feces; make and absorb vitamins

Pancreas

Secretes enzymes to digest carbohydrates, lipids and proteins; secretes insulin and glucagon

Liver

Detoxifies blood, produces bile (which breaks down, or ‘emulsifies’, fats)

gallbladder

stores bile

Spleen

Destroys and makes red blood cells; produces antibodies for the immune system

What is peristalsis?

Contractions of smooth muscle in the esophagus to help us swallow

What is the function of the excretory (urinary) system?

Remove waste (excess water, carbon dioxide, proteins, sugars) from the body

kidney

Removes waste products from the blood; maintains blood pH, regulates the amount of water in the blood.

ureter

Tube that carries urine from kidney to bladder

bladder

stores urine

Urethra

Tube that carries urine from bladder to outside of body

The kidneys filter all of the blood in the body every \____5. A person can live without one of their kidneys. True or false? \_____

45 minutes; True

Define puberty.

Period of time where adolescents reach sexual maturity and are capable of reproduction

scrotum

an external sac that hold the testes at a couple of degrees cooler than the human body

Seminiferous tubules

Hundreds of tiny tubes where the sperm are produced (meiosis; spermatogenesis)

Epididymis

Where the sperm mature and are stored before ejaculation

What are the primary functions of the female reproductive system?

Produce mature eggs every 28 days and prepare the body for pregnancy

Define ovulation.

The process in which an egg or eggs are released from one or both ovaries.

Fallopian tubes

Have cilia (hairs) that “sweep” egg into the uterus and there the sperm find the egg for conception

Uterus

Where the fertilized egg implants and grows and develops for 40 weeks (9 1⁄2 months)

Placenta

Develops in uterus during pregnancy Allows for mom’s blood vessels and fetal blood vessels to be close together for transfer of carbon dioxide and oxygen, nutrients and waste between mother and baby

What is the function of the nervous system?

Collects sensory input and conducts impulses around body so body can respond to external and internal environmental changes

The layers that surround the brain are called \______

meninges

Cerebrum

Largest part of brain; involved in thinking, logic, learning, judgment, intelligence, emotions, conscious thought and conscious movement,

Cerebellum

Coordination of muscle movements such as posture and balance

Medulla oblongata

Part of the brain stem; regulates INVOLUNTARY survival functions such as blood pressure, heart rate, breathing, digestion, vomiting, swallowing, defecation and blinking

what does DNA stand for?

Deoxyribonucelic Acid

what are the 2 reasons why DNA is unique?

contains our genetic codecopies itself exactly

what are the building blocks (monomers) of DNA?

nucleotides

what are the 3 parts of a nucleotide?

deoxyribose, phosphate group, nitrogen base

what are the four nitrogen bases present in DNA?

Adenine, Guanine, Thymine, Cytosine

what are purines? how many rings do they have?

Adenine and Guanine; double rings

what are pyrimidines? how many rings do they have?

Thymine and Cytosine; single rings

The double helix structure of DNA was discovered by 4 scientists - what are their names and what was the year?

DNA was discovered in 1953; Rosaline Franklin, James Watson, Frances Crick, Maurice Wilkins

What did Erwin Chargaff discover?

the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal.

What is the “backbone” of DNA made up of?

Deoxyribose and phosphate group

what holds the DNA molecule together?

hydrogen bonds

The nitrogen bases are always connected to the (sugar or phosphate)?

sugar

What enzyme “unzips” the 2 strands of DNA in DNA replication?

DNA helicase breaks the hydrogen bonds between the nitrogen bases.

what does DNA polymerase do?

adds new DNA nucleotides and creates a new strand during replication.

What are the 3 types of RNA?  What does each type do?

Messenger RNA; carries genetic info of DNATransfer RNA; bonds to a specific amino acid and carries the amine acid to the ribosomeRibosomal RNA;  functions in the ribosomes as a metabolic molecule that aids in protein synthesis

what are the 4 differences between DNA and RNA?

DNA; two strands, deoxyribose, has Thymine, replicates on its own RNA; 1 strand, Ribose, has Uracil, doesn't replicate on its own

What is transcription?  Where does it occur in the cell (nucleus or cytoplasm)?

RNA molecules are produced by copying part of the nucleotide sequence of DNA into a complementary sequence in RNA. occurs in the nucleus.

briefly describe the steps of transcription.

the process that takes the information passed from DNA as messenger RNA and turns it into a series of amino acids bound together with peptide bonds.

What enzyme is responsible for transcription?

RNA polymerase

How does mRNA move from the nucleus to the cytoplasm of a cell?

through nuclear pores

What are introns?

allow for alternative splicing, making it possible to generate multiple proteins from a single gene.

what are Exons?

The sections of DNA (or RNA) that code for proteins are called exons.

A series of 3 mRNA nitrogen bases that contains the information needed to make proteins are called what?

codons

What is the universal start codon and what amino acid does it code for?

AUG; methionine

What are the 3 stop codons?

UAA, UAG, UGA

What is translation?  Where does it occur in the cell (nucleus or cytoplasm)?

mRNA strand is translated into a chain of amino acids (PROTEINS), in the cytoplasm, at the ribosome.

What does the word “mutation” mean?

to change

Mutations that produce changes in a single gene are called

gene mutations

Mutations that produce changes in whole chromosomes are known as

chromosomal mutations

In what way(s), if any, do most mutations change organisms

many if not most mutations are neutral.

What are the 3 examples of gene (point) mutations?

Substitution, deletions, insertions

Insertions and deletions usually result in frameshift mutations.  What does this mean?

Shifts all the bases, and can change the amino acid.

What are the 4 examples of chromosomal mutations?  Explain each.

deletion; the loss of all or part of a chromosomeduplication; produces an extra copyinversion; reverses the direction of parts of a chromosometranslocation; when part of one chromosome breaks off and attaches to another

what is one of the functions of DNA?

store genetic information for the cell

what is DNA shaped like?

a double helix

what does “replication” mean?

when DNA copies itself exactly

how did Mendel set up his experiments?

For step 1, to get the parental generation, Mendel allowed pea plants to self-fertilize for many generations and grew the seeds from these plants. He then cross-fertilized the two different parental varieties for the F1 generation where they were all purple flowers and grew the resulting seeds. Finally, Mendel allowed the F1 generation plants to self-fertilize, resulting in the F2 generation, and white flowers reappeared.

anitgens present in each blood type

same, o\= none

Possible genotypes

IA, IA: IA i IA, IB, II

antibodies found

A: B

B: A

AB: none

O: AB

What is the rH factor? Why is it important during pregnancy?

The type of protein (antigen) found on red blood cells

what blood type is the universal donor?

Universal Donor; O- because it has no antigens, it will not trigger an immune response, even if the recipient has a different blood type

What blood type is the universal recipient?

Universal Recipient; AB+ because they can receive antigens from all blood types

what is the most common blood type?

O positive